MadModder
Gallery, Projects and General => Project Logs => Topic started by: raynerd on July 31, 2013, 06:55:32 PM
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Good evening,
I've just returned from a week in St Ives Cornwall, in which my wife, daughter and I had laugh wasting a few quid on a penny pusher machine on the arcade on the sea front. I fancy having a bit of fun and trying to build one as it would be a great entertainer and with a "house pot" built into these things, it'll also be a novel way of saving.
The machine I intend to make will be more or less full size with plenty of feature creep going into it along the way. I'm off for 4 weeks so that is the timescale I'll have although we have a few caravan breaks along the way.
Not your usual engine, machine tool or invention....but I think it passes for an acceptable madmodder thread?
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Got given a Ford Fiesta wiper motor today just after Dave had kindly offered me a 12v motor over on the windscreen wiper thread I started in the electronics sub forum. Cheers Dave, much appreciated for the effort and gesture :beer:
Being impatient, I went to maplin and spent £15 on a Pwm controller instead of £8 on eBay.
Problem is, I get a bad squealing with the Pwm controller!
I'm not a motor man so would appreciate any thoughts. I very rarely speak on my videos, must have felt chatty this evening...!!!
Hopefully buy some wood and start a plan for the push table tomorrow.
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....but I think it passes for an acceptable madmodder thread?
Anything you build qualifies :beer:
but what is a penny pusher? I think I know but I am not sure. :scratch:
Eric
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One of these Eric :
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[/quote]
but what is a penny pusher? I think I know but I am not sure. :scratch:
Eric
[/quote]
My wife is addicted to them ! We live 6 miles north of Hastings, and the sea front there is crammed with them - gets quite tedious as you can't drag her away. I try to avoid, but the grandchildren seem to form a good excuse for trips !
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Hi Chris
Been there ... the motor armature is resonating at an audio frequency (ies).
Some motors just don't like PWM :bang:
Once had a Volvo truck radiator fan motor that gave no end of aggro.
Had to drop the PWM base freq. to 40-ish Hz, even then it was not good. Tried going up in freq. but all it did was squawk chromatic scales as you changed the revs. Amusing at first but then became irritating ...
Do you know the base freq. on the Maplin controller ?
Does it have a suppression diode on the O/P ?
You MIGHT try blunting the O/P by slapping a GOOD cap. across the motor, the resonating voltages can be very high, IIRC I once shut one up a bit with a 8uF motor start cap. Don't use an electrolytic, it may well have a brief and brutish life.
Bit of a bugger buying off-the-shelf stuff, you're more or less stuck with it.
Which is why I nail my own junk together.
At least if it works I can feel triumphant, or alternatively, smack it about until it does ... and if it never works, sling it under the bench and pretend it didn't happen ... :scratch:
Dave
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Hey Bluechip
On the spec sheet for the regulator it says edge to edge frequency: minimum 1136hz, max 1250hz, average 1200hz - nothing about a base frequency!
Any more thoughts.... What do you mean by a "good" cap?
I'd prefer to use the Pwm controls if I can.
Chris
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Hey this looks interesting. I've always secretly wanted to build an arcade machine similar to my hero's, Tim Hunkin (http://www.timhunkin.com/), but the thing stopping me is visions of trying to goad reluctant family members into trying it out. The elaborate piggybank is a great way to give it a purpose beyond entertainment.
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Chris
Pic I got from here
http://abertoatedemadrugada.com/2013/04/o-que-e-o-pwm.html (http://abertoatedemadrugada.com/2013/04/o-que-e-o-pwm.html)
Top row, if you imagine the pulses are right to left in time. the LH edges are all the same.
So, the frequency is F = 1/t. This is the base frequency, otherwise known as the PRF. ( Pulse Repetition Frequency ).
To take an easy eg. PRF is 1 kHz, if I have a pulse length of 1mS, the trailing edge of pulse 1 will be co-incident with the leading edge of pulse 2. ie. It's on all the time. 100% modulated.
If your doo-dah is 1.2kHz, then that is well within the audible range.
I do PWM with pic 16F886, and you can get a PRF of several kHz which takes ( hopefully ) most of the squawk well above audible.
BTW that motor is not on a desk top is it? Not got a sounding board effect have you?
I have some steppers that kick up the most hideous clatter until I pick them up ..
Good Cap ??
OK
If you shove a sharp edge pulse through an inductor ( your armature winding ) you will get a back e.m.f. the voltage dependent on the rate of change of current.
ie. -V = L x ( di/dt )
Numbers ??
Inductance = 10mH
Pulse rises from 0 to 5A in 100uS
-V = 0.01 x ( 5 / .0001 )
Some 500V - ish of nasty voltage spike ??
You need a cap. that is made to tolerate such nonsense ... not you average electrolytic eh ??
I have no idea what your motor inductance is or what the rate of change of current is either, but the effect IS there to some extent or other ...
The preceding stuff is from memory BTW, but I think it's right ... :scratch:
Poor 'owd codger ...
Dave BC
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Just in case you're not really interested, and seeing as it's too damned hot in the shop ... :thumbup:
Did a couple if piccys of the effect of driving a square wave current through a 22mH inductor.
Done on my venerable Hitachi V423 oscilloscope, vintage 1985 ( 1985 AD I might add. If it was much older it would be a fossilloscope, but I won't mention that. )
Using the 1kHz 0.5V pk calibration jack. which I doubt is capable of driving much in the way of amps ..
Shows the ringing which the choke causes, as you see they are several times the frequency of the driver pulse, so, if you make your PRF high enough, most of the junk is hopefully above audio ..
Dave BC
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Chris,
Usually an inductor that is being switched, I.e like your motor, would have a resistor and a capacitor (a snubber network to dampen the ringing) and a hi PIV diode across the motor......
taking the switching frequency to somewhere around 10Khz will eliminate the whine......If you go to Vellemans website and look up their pwm kit,look at the schematic especially around the output stage.That will explain a lot...(hopefully )
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Hi
I just spent 1/2 hour trawling through the maplin website and I can't see that pwm controller that you bought.
have you got a code number or is it discontinued now?
cheers
Roy
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Hi
I just spent 1/2 hour trawling through the maplin website and I can't see that pwm controller that you bought.
have you got a code number or is it discontinued now?
cheers
Roy
One of these ???
http://www.maplin.co.uk/panel-mounted-speed-regulator-module-30310 (http://www.maplin.co.uk/panel-mounted-speed-regulator-module-30310)
Looks a bit like it. Although why they use the word 'regulator' rather than 'controller' I have no idea.
And knowing Maplins .. neither would they ... :lol:
Dave
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Typical maplins :doh:
thanks.
Roy
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Bluechip - so basically, am I correct in thinking based on your information that it is the Pwm controller and its specific base frequency that is causing a frequency in the audible range?
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I'm no woodworker but £15 lighter after spending it on 18mm MDF have this together. It is took me a good few hours. I've no tool to rebate the inside of the window for Perspex - hummmm, not sure how I'm going to get plastic into this windows and make it look acceptable :-S
Mine and my daughter best efforts.
(http://raynerd.co.uk/wp-content/upLoads/image5.jpg)
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looking at the photo of the unit I'd say the pwm is based on 555 timer chip....yes the pwm frequency is set by the module.....
if this is the case,check to see if pins 6&2 are connected together :
There should be a cap between pins 6/2 and pin 1
Reducing the cap value by a factor of ten will increase the frequency ten fold......See how you go with that...
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I'm no woodworker but £15 lighter after spending it on 18mm MDF have this together. It is took me a good few hours. I've no tool to rebate the inside of the window for Perspex - hummmm, not sure how I'm going to get plastic into this windows and make it look acceptable :-S
Mine and my daughter best efforts.
(http://raynerd.co.uk/wp-content/upLoads/image5.jpg)
(http://iforce.co.nz/i/kpvjpybu.nfm.jpg)
Something like this might work. The rails could be glued and/or screwed on. Hope it's clear.
They might also serve to strengthen those struts. MDF is a bit of an odd material and tends to sag over time when used in things like shelving.
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Bluechip - so basically, am I correct in thinking based on your information that it is the Pwm controller and its specific base frequency that is causing a frequency in the audible range?
Chris
Yes errr -ish :scratch:
Whether you like it or not, every mechanical device has a resonant frequency, including any bits that are in it. So, imagine we have a PWM controller running at 1kHz. Every 1mS the armature gets a kick of current producing a kick of magnetic field which interacts with the permanent magnet field and jerks it round a bit. Now we have converted electrical pulses to a mechanical vibration. If there is some bit wanting to vibrate at 250Hz it will get what it wants every 4th poke from the armature and vibrate it will. ****tering wine glasses trick etc.
I'm not quite sure why you are going the PWM route on a bit of kit that will run at just one speed. I would determine the DC volts required and make a linear, possibly with something like a L200 ic.
PWM is nice for lots of motor antics but it's not the only way.
Dave BC
EDIT Why do I get ***** s h a t t e r i n g is not a profanity AFAIK
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Probably because sh something t sounds like sh something else t. :Doh:
Roy
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:offtopic:
I don't see why ...... like most folk on here I'm fairly well corrupted anyway. I doubt if coming across 's h a t' in plain text is going to make matters much worse.
Anyway, if you go back a few hundred years, most of the now 'naughty' words were in common use even in Parish Records etc. etc.
Even including the 'F' one although it had an 'e' on the end for some reason... :scratch:
end of :offtopic:
Dave
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Looks good, and S.Heslop's suggestion does as well!
If your daughter invites lots of friends over for play dates, this could end up being quite profitable. I'm going to have to watch this thread closely!
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Looks good, and S.Heslop's suggestion does as well!
If your daughter invites lots of friends over for play dates, this could end up being quite profitable. I'm going to have to watch this thread closely!
Yeah, I can see Chris 's daughter capitalising on this project :)
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I'm
not quite sure why you are going the PWM route on a bit of kit that will run at just one speed. I would determine the DC volts required and make a linear, possibly with something like a L200 ic.
Seconded.
Pwm can erase the magnets in pm motors .
If you have a variable power supply, just adjust it until the speed is as required then pick a transformer to give about same volts (when rectified) KISS principle is best for this kind of application :-)
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Hi guys, thanks for the interest!!
I just thought pwm would give me control of the speed as I'm not sure exactly what speed will work best. Anyway, taking your advice, 9v seemed about the correct speed. Looked in my box of old supplies and to my luck 9v. 1500mA. One of those small Chinese made supplies. Anyway, connected it up and it moves at about 1/2 RPM is there really jurky fashion!!
I must be making an obvious mistake :-(
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Hi guys, thanks for the interest!!
I just thought pwm would give me control of the speed as I'm not sure exactly what speed will work best. Anyway, taking your advice, 9v seemed about the correct speed. Looked in my box of old supplies and to my luck 9v. 1500mA. One of those small Chinese made supplies. Anyway, connected it up and it moves at about 1/2 RPM is there really jurky fashion!!
I must be making an obvious mistake :-(
Possibly because it's a switched mode device, never intended to drive a motor.
It may well be going into over-current, shutting down, coming back up, over-current, shutting down etc. etc. ad nauseum.
I assume you are aware that Chinese milliamps aren't as big as real ones ??
That motor, at switch on, is going to look pretty damn close to a short circuit ... they all do.
Dave BC
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Yep, I did think the answer would be something like that.
Now to try and find a 7-9v supply suitable! :-(
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How about a 6 volt transformer, a bridge rectifier and a big capacitor paralleled with the output? Good old fashioned tube (valve) filament power supply. 3 parts.
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Okay, okay, add a fuse and a power cord and a box, etc.
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I did test the original controller you were interested in, made a video of it running, and gave you speeds and current draw as requested.
And as you can hear in the video, no hum. Just gear noise.
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Those last pesky details.. :lol:
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Wouldn't even use the capacitor, DC PM motors run quite happily on rectified AC.
Dave BC
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Hi guys, thanks for the interest!!
I just thought pwm would give me control of the speed as I'm not sure exactly what speed will work best. Anyway, taking your advice, 9v seemed about the correct speed. Looked in my box of old supplies and to my luck 9v. 1500mA. One of those small Chinese made supplies. Anyway, connected it up and it moves at about 1/2 RPM is there really jurky fashion!!
I must be making an obvious mistake :-(
How much current does the motor draw? Mayne be too much for the supply - windscreen motors tend to be quite beefy and not too efficient so may require more power than you expect .
[Edit]
Just measured a two speed wiper motor at 1.2 and 2.2 amps at 9v (unloaded ) it draws about the same at 12v
Power on surge could easily be 10amp!
Somewhere, i have a circuit I designed for a positive feedback (resistance compensated) speed controller ...
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How much current does the motor draw?
http://madmodder.net/index.php/topic,8810.msg96161.html#msg96161
This has already been tested, is rated at 10 amps and works:
http://madmodder.net/index.php/topic,8810.msg96103.html#msg96103
As shown here:
http://madmodder.net/index.php/topic,8810.msg96117.html#msg96117
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Used a few ATX supplies for various jobs over the years.
They have a 5v line and 12v - do they have a 7?? If not, maybe this is terrible electronics but wont using the 5 and 12v lines give me a potential difference of 7v ?? :zap:
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Beware: Often, PC power supplies will not start up unless there is a load on (usually) the 5v supply. This supply is used as the one for feedback for voltage regulation, and all the others remain at voltage by ratio.
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Used a few ATX supplies for various jobs over the years.
They have a 5v line and 12v - do they have a 7?? If not, maybe this is terrible electronics but wont using the 5 and 12v lines give me a potential difference of 7v ?? :zap:
Yes it will, but it won't be 7V emf ... :thumbup: think about it ...
A 12V supply pushing out current through a load to 0V
A 5V supply doing the same ... ie out
OK . as awemason rightly says most ATX's wont power up unless the 5V is loaded, often to about 1A. which means a 5R resistor.
PSU :thumbup: now comes up OK ...
Now connect your motor from +12 to +5 , the motor can now sink it's current through the 5R resistor
Except it's start current will be ( modestly ) 3A which will try to drive the 5V O/P up to 15V.
Well it won't get there 'cos it's only got 12V to start with.
The 5V will not see the funny side of the joke, will sense over/voltage and shut the ATX down.
You need to visit the difference between 'PD' and 'EMF' and 'sourcing' & 'sinking'.
The 5V supply can only source 5V, the chances are it can't sink the 12V.
Not while it's alive anyway ...
You seem to be looking for the most abstruse solution you can devise to a non-problem :lol:
AS Bill Todd, VTSteam et al have alluded ..
Get a 0-6 0-6 50-ish VA transformer, nail it to a 15A bridge rectifier, switch on, slide off for a pint while you leave it to ekkle.
Dave BC
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The one secret we haven't mentioned to Chris is..............
a 6V transformer when connected to a bridge rectifier will give you sommat more 'an 6 V DC. output.
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Here, a picture is worth a thousand words.
This is for a simple transformer -- and according to Bluechip you can eliminate the capacitor as well.
Or if using a center tapped transformer, you don't even need 4 diodes, or a full wave bridge package. Just two diodes (I believe, or is it 1?)
The only problem with all of these, as you say Chris, is, they aren't adjustable. But if they're right, you're good to go
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Not if you omit the capacitor. It'll just see the rms .
It will actually be a bit more than 6V rms with a 50VA tranny 'cos 50VA is a bit over-rated for the job.
It will be up a tad because of the favourable load regulation.
Not looked but I would guess the load regulation would be about 10% with a 50VA tranny ..
:beer: time for me .... as one J Reeves once said 'I hear the sound of distant Becks' and I don't intend it to be distant much longer ...
Dave BC
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The simplest solution in my opinion is a suitable transformer, followed by a bridge rectifier and capacitor, followed by the pwm unit Chris has already bought. This way as he builds the penny pusher he can adjust the speed to suit. The speed will depend on the load and this will probably change as the design develops, so a fixed speed solution is not a good idea. Build a little 'post design design' into it for later tweaking !
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Hello chaps.... I think what you are failing to realise is that I haven't got a bloody clue when it comes to understanding electronics!!!! So David,
You seem to be looking for the most abstruse solution you can devise to a non-problem
AS Bill Todd, VTSteam et al have alluded ..
Get a 0-6 0-6 50-ish VA transformer, nail it to a 15A bridge rectifier, switch on, slide off for a pint while you leave it to ekkle.
So although I appreciate this was said in fun and honesty, without a clear guide as to exactly which transformer to purchase, which bridge rectifier and exactly how to glue it all together I'm useless and it is likely to go pop!!! :zap:
I suppose my suggestions have all been ideas based on purchasing a psu or converting an existing psu I.e the ATX supply!
I do appreciate all the info so please keep it coming!! I'm in a caravan now until Sunday so no more progress tomorrow. Time to think and decide on exactly how to power it.
I do also agree with awemawson - I'm not 100% sure what speed is best so using a Pwm does provide some flexibility but accept with the problems it is causing, it just adds another problem!!!
Hummm...tricky!
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I had a feeling Chris needed more than just generic advice.
Okay, Chris, I'm going to vote for the very first thing you asked about, not the PWM Controller you have now, but the one on Ebay, that you first mentioned and I also have, and that I have connected to an ATX PSU, which you also have and seem to be familiar with. And I have run it with a windscreen motor.
Now, since this outfit has already been tested with a windscreen motor, since it is cheap, and uses your available parts, and you only have to buy one thing, that controller, as opposed to a bunch of things -- transformers, rectifiers, capacitors, it's easier and doesn't require building something.
Also, since the pwm controller you have now isn't satisfactory, put it on the shelf for some other purpose, or return it for more than the Ebay one costs, and smile all the way to the bank!
Now if you do this, please make sure that your ATX power supply has at least 8 amps available on the +12 output, and you will need to do a couple thngs to it to make sure it comes on, and has a load on the 5 volt line, as someone else mentioned earlier. But that's not hard to do. And we can help with that.
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:) have ordered the new pwm controller and will get onto sorting an Atx supply on Monday!! :-)
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Maybe you already know how to rig an ATX power supply -- I seem to remember that you did a motorized spindle once -- did that use an ATX?
Anyway, the two things you need to do are 1.) make a connection to the power supply's switch line to tell it to turn on. And 2.) put a load on the 5 volt side so the power supply has something to sense and regulate. Usually that is a power resistor.
However, I'm guessing that you are going to want lights in your arcade game, so why not use the 5 volt lines to power those?
Then you won't need a power resistor as a load on the 5 volt side -- the lights will be that load. Whether incandescent or LED just make sure they will be comfortable at 5 volts. Probably 6 volt automotive lamps (if you can still get them there -- we can here) will probably work well enough. Or hook up LEDs so they can handle 5 V. Some can, lesser ones can be hooked in series, or have a dropping resistor, etc.
If this sounds like a lot of jargon, just ask, and we can walk you through it. If not, you're on your way....
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Hey Vsteam, thanks for the details. Yes, I've hooked up a good few different ATX supplies for various CNC machine axis and the spindle as you mentioned. Good point about running the LEDs and lighting off the 5v line.
Just some progress on the mechanism
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One more thought Chris, and others could probably correct or amplify this, I think you will need a certain minimum amount of current draw on that 5 volt line to keep the power supply healthy.
LEDs are usually pretty efficient. And if you use low power ones, and not very many, there might not be enough current draw between them to be a good "dummy" load. Incandescent bulbs on the other hand tend to be more wasteful, and draw more current, which in this case is maybe a good thing. Whichever you choose, try to draw enough current to equal what the usual dummy load resistor is on these conversions.
Perhaps someone else can suggest a reasonable current draw minimum.
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It is a good point since I expect when I initially want to test the supply on the motor I won't have any LEDs at all. I'll load the 5v line as I usually do with a resistor initially.
Just got back out of the workshop and very chuffed. I know it seems insignificant but I've been having a hell of a job sourcing some tiny slides. It isn't critical enough to use proper linear slides and bearings and too pricy. I've wanted to use a ball bearing draw slide but they are too long. Went to BQ earlier and there was one lone 12" slide, too big for me but it wasnt in a packet of a pair. Decided to ask if they would sell it me and they asked for £3!! I've spent many many thousands over the year but I have never walked out thinking I'd got a good buy ..... A first time for everything.
Anyway, I chopped it in half tonight. Stripped all the 3 segments apart, ground off any stops, removed the bearings, removed and disposed of the outer extension (telescopic 3 section and I only needed 2 sections), cut it in half and re-assembled.
Two really neat, mini slides!
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Chris,
I thought you might be interested in these :-
http://uk.farnell.com/hamlin/59140-010/sensor-magnetic-spst/dp/1839038?Ntt=59140-010
They are magnetic switches, when approached by a magnet, the switch closes, they are very easy to set up when compared with mechanical limit switches. They will switch a relay or light diodes. Given as 10watts at a maximum of 200 volts they are pretty flexible.
Regards, Matthew
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Hey Matt, they do look interesting, do you have a specific use in mind with relation to this project.
Got a moving table. It will need to be rebuilt as the link arm is too long and wasting far too much space.
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Chris,
Have you considered the not insignificant weight of a table of pennies or 2p pieces? The frictional load will be quite a bit I suspect as it pushes forwards. The actual movement of the pusher is somewhat less than on your prototype.
Don't forget that when the pennies tip over the edge in the commercial machine, a portion of the 'haul' is split off by a divider so the punter only gets about 75% of what falls - the remainder re-circulates.
Andrew
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On the pwm controller, do you have a free-wheel diode across the motor? I've had experience where the motor would vibrate and the diode corrected it.
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Sorry about that, I got my wires crossed, I don't know why, I thought that I'd seen something about limit switches on your thread, I've been back over it and I can't see where I mis-led myself!
Regards, Matthew
Chris,
I thought you might be interested in these :-
http://uk.farnell.com/hamlin/59140-010/sensor-magnetic-spst/dp/1839038?Ntt=59140-010
They are magnetic switches, when approached by a magnet, the switch closes, they are very easy to set up when compared with mechanical limit switches. They will switch a relay or light diodes. Given as 10watts at a maximum of 200 volts they are pretty flexible.
Regards, Matthew
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Chris,
Have you considered the not insignificant weight of a table of pennies or 2p pieces? The frictional load will be quite a bit I suspect as it pushes forwards. The actual movement of the pusher is somewhat less than on your prototype.
Don't forget that when the pennies tip over the edge in the commercial machine, a portion of the 'haul' is split off by a divider so the punter only gets about 75% of what falls - the remainder re-circulates.
Andrew
Andrew, regarding the weight of the pennies, are you saying that the motor won't cope with it or I'm not sure? I do appreciate a table of pennies will be a significant weight.
Regarding the house winnings, all the commercial machines I have seen have the hidden trap at the edges. ALL the coins that fall off the front lip are won by the punter however there is a small slot, normally about 15mm x 70mm along either edge of the machine. Coins that fall into these slots of eaten by the machine. The hidden slot is normally covered by a small flap.
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On the pwm controller, do you have a free-wheel diode across the motor? I've had experience where the motor would vibrate and the diode corrected it.
Not that I know of... :zap:
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:Doh:
Chris,
Usually an inductor that is being switched, I.e like your motor, would have a resistor and a capacitor (a snubber network to dampen the ringing) and a hi PIV diode across the motor......
taking the switching frequency to somewhere around 10Khz will eliminate the whine......If you go to Vellemans website and look up their pwm kit,look at the schematic especially around the output stage.That will explain a lot...(hopefully )
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I suspect you may run out of pushing power with the degree of movement you currently have. Of course this is just a guess, and if you do reduce the crank travel it will increase the available torque.
Are you going to have the two tier pushers allowing two levels of cliff edge that the commercial one have?
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:Doh:Chris,
Usually an inductor that is being switched, I.e like your motor, would have a resistor and a capacitor (a snubber network to dampen the ringing) and a hi PIV diode across the motor......
taking the switching frequency to somewhere around 10Khz will eliminate the whine......If you go to Vellemans website and look up their pwm kit,look at the schematic especially around the output stage.That will explain a lot...(hopefully )
??
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British penny weighs 3.56 g, two pence coins weigh 7.12 g. Two pees are far more common, you can see 5p, 10p, 20p, 50p and pounds (and even banknotes), but the average should be a little below 7 g. The 25p and £5 coins are not actually in circulation, only commemoratives, and very large and heavy (28.28 g each). A thousand coins would be about 7 kg. Heavy, alright, but it's not a showstopper.
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:Doh:Chris,
Usually an inductor that is being switched, I.e like your motor, would have a resistor and a capacitor (a snubber network to dampen the ringing) and a hi PIV diode across the motor......
taking the switching frequency to somewhere around 10Khz will eliminate the whine......If you go to Vellemans website and look up their pwm kit,look at the schematic especially around the output stage.That will explain a lot...(hopefully )
??
Chris, John is suggesting putting three electronic parts across the terminals of your present motor, if you use your present speed controller that whines. The intent would be to stop that whine.
The three components he is talking about are a capacitor, a resistor and a diode.
A high PIV diode just means a diode that has a high voltage rating, in other words it isn't going to burn out when it gets a momentary spike of voltage. So if your motor is expected to see about 10 volts maximum, you would pick a diode that is about 4 times that (or more) in rating. A 50 volt capable diode would be fine, and so would a 100 volt capable diode.
Here in the States we have Radio Shack, where we can walk into the store and say to the clerk "Gimme a 50 volt diode!" and he would then consult with others there until someone would eventually lead you over to a display with drawers one of which said "DIodes and Rectifiers" and he would then depart. You would open the drawer and find a small section that said "SILICON DIODES 50 VOLT" or 50 PIV, and then buy one or ten if packaged that way.
Anyway, since you sent for the other controller, you may not have the hum problem -- I don't on the wiper motor I used, and I hope yours will be the same.
With regard to pushing the weight of pennies, were you thinking of a low friction material, like fomica (countertop material)?
I would think pennies would slide pretty easily on that. Also, the way this works is by averaging just like a drop of water falling an inch into a bucket. You could say that the drop moves 10 kg of water. But it doesn't move it very far. The pennies work the same way. Each penny may move many others (but usually not all of them by a long shot) but the ones it moves move only a small portion of its movement. Pennies fall because they are usually on the edge and reguire only a very slight movement to topple off. Thus there is a mechanical advantage inherent in the whole process of moving coins. You would never move all of the coins, and the ones you move move less than one penny width.
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That "high PIV" diode is what is called "free-wheel" diode.
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The commercial ones have a cascade of usually two pushers and shelves, and the coins build up to quite a thickness - up to two inches at times
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This is a great project Chris but have to admit am glossing over the electronics bits - straight over my head!
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The commercial ones have a cascade of usually two pushers and shelves, and the coins build up to quite a thickness - up to two inches at times
Don't forget the magnets to help them stay on the shelves :thumbup:. The copper like euro cent coins are "magnetic material" plated copper. The others, I never tested if they are attracted or not.
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Hi guys, I'll just say again thanks for the interest!
Andrew - I'm really not expert on playing these machines but all the ones I played and the ones on youtube just have a single tier:
http://m.youtube.com/results?q=coin%20pusher&oq=coin%20pusher&gs_l=youtube-reduced.3..0l4.656.2140.0.2269.11.4.0.7.7.0.98.317.4.4.0....0...1ac.1.23.youtube-reduced..0.11.392.pY7cXzUxUA8
That being said, I think I have seen what you mean, where they have multiple stages. This one is just going to have a single stage!!
The only thing I'm considering, is adding a coin spinner in the centre... A small motor with a propeller arm - if the coin hits when dropped, it'll fling it somewhere random.
NickG - the electronics is over my head as well! I'm getting there thanks to the folk on here.
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The only way to know if it is too difficult for your motor is to try it out. The length of the arm is going to be fixed by the stroke you want. Check the current with an ammeter to make sure it seems reasonable.
One option if it is too much for the motor and required stroke and current requirement would be to use a couple of additional gears (I know you can make those!) or a toothed rubber belt and run the motor at a higher voltage.
One other factor in your favor, however, is that the start of the push, where friction/inertia is likely to be highest is also the point of maximum thrust and mechanical advantage by the crank arm.
My windshield wiper on my car has to drive two 18" blades plus connecting linkage, with cold grease in the linkage at temps below freezing, and wipe snow off of a five square foot area at the end of a 10 inch moment arm. So I think you have a good shot at success.
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Noitoen mentioned about magnetic materials, as some euro (or euro cent) coins are, and also the British coinage. Good point. 1p and 2p are copper-plated steel, 5p and 10p are the new coins made of nickel-plated steel. The rest (bigger denominations) are not magnetic (all others are varying percentages cupronickel, £1 is nickel-brass).
Depends on what you want for these magnetic materials. E.g. you might want a "clean and level field", like a formica or corian table tops, or stainless steel might be feasible (it slides easily). But a steel plate top might not be a well-received idea. Some Neodymium magnet "pills" would accumulate for enormous coin mounds...
That's a very good idea, your penny pusher! :clap:
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Yeah i think the wiper motor will have enough torque, the worm and wheel
Will give quite a reduction would
Imagine in the order of 20:1? Imagine that with conventional gearing ... A 20 tooth going to a 400 tooth.
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This is a great project Chris but have to admit am glossing over the electronics bits - straight over my head!
You only have to shout out if you need help.... :zap:
There are plenty of knowledgeable folk on here, someone is bound to have an answer to a question ( err...just dont include me...I know nothing... :scratch: :zap: )
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Hi,
When I started reading this thread I was doing a job on my little X0 mill that needed a lot of slots cutting in it, I also plan to make quite a few of these and was thinking how great just some basic power feed would be.. :proj:
So when I read this thread a big light went on. I could use a wiper motor !!!!!.
So not half an hour later a few ebay purchases were secured.
Yesterday these turned up.
The motor cost £6 inc postage as it didn't park the wipers any-more - no problem for me.
It's from a Corsa C, comes apart easy, is well built mechanically and shows hardly any signs of wear.
The controller is the £8 one from etang. It has well specified parts and works great with the motor on both the low and high speed connections.
I've included a schematic I drew for those interested, it includes all the protection required with no extra parts needed.
Base frequency measured on my scope is about 16.5 Khz.
I hope the manufacturer/seller doesn't mind me putting this in but there is no way I could build this for £8 anyhow so I can't see it can harm. (untested circuit - build at your own risk values etc may be wrong.)
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Thanks for the schematic -- that should be useful for mine if it needs repairs some day!
I'd love to see your final setup on the mill when you build it. That's what I bought mine for, as well.
Hope you saw this for additional info:
http://madmodder.net/index.php/topic,8810.0.html
also of interest:
http://www.mini-lathe.com/Mini_mill/Modifications/Power_feed/power_feed.htm
There are other sites on the net and I think a series in HSM magazine some time back -- mill drill adventures?
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Hi,
When I started reading this thread I was doing a job on my little X0 mill that needed a lot of slots cutting in it, I also plan to make quite a few of these and was thinking how great just some basic power feed would be.. :proj:
So when I read this thread a big light went on. I could use a wiper motor !!!!!.
So not half an hour later a few ebay purchases were secured.
Yesterday these turned up.
The motor cost £6 inc postage as it didn't park the wipers any-more - no problem for me.
It's from a Corsa C, comes apart easy, is well built mechanically and shows hardly any signs of wear.
The controller is the £8 one from etang. It has well specified parts and works great with the motor on both the low and high speed connections.
I've included a schematic I drew for those interested, it includes all the protection required with no extra parts needed.
Base frequency measured on my scope is about 16.5 Khz.
I hope the manufacturer/seller doesn't mind me putting this in but there is no way I could build this for £8 anyhow so I can't see it can harm. (untested circuit - build at your own risk values etc may be wrong.)
That "A2" diode is the freewheel diode :thumbup:
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Very pleased this thread has become useful for more than just building a fun arcade game.
My controller also arrived today and I managed to pick up an old atx supply for £5 from a PC repair place. Spent two hours hooking up my atx supply with no luck and pulling my hair out, only to realise the fuse had blown in the kettle lead I was given! :doh:
Anyway- perfect, nice and quiet and runs lovely. I've also painted the deck and screwed down some Florescent red Perspex which my daughter likes the look of.
Lots more to do but progress is being made!
(http://raynerd.co.uk/wp-content/upLoads/image6.jpg)
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Chris
That's interesting. Do you have it working from +5V to +12V for the 7V or from the 12V direct ??
Don't bother about the fuse. It happens ...
Couple of months ago I was about to rip my shop vaccy to bits, until I found out the switch on one side if a double 13A socket had packed up ... :bang:
Ah well ...
Dave
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Interesting project are you going to put a fiver in there as a incentive for the kids to spend all their pocket money in it?
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Chris
That's interesting. Do you have it working from +5V to +12V for the 7V or from the 12V direct ??
Dave
12v line directly Dave.
A fiver - I expect it will take many many times that to fill it so that it is playable!
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This would be the best present ever - remember the alarm in-case anybody tries to tamper with it!!
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Cheers Nick, she is very excited about it.
Like I keep saying, I`m actually building it as an elaborate saving/money box for my wife and I! Money will always be falling down the house collection box and therefore saving it. My idea is that the 10p's falling down the "house" shoot will fall into the hopper - these can then be changed out in a change machine I`m building in the machine lower down. That is the intention anyway!
Chris
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Now come on Chris be open with us. We KNOW it's going in the school playground to fund the Common Room gin fund
:lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol:
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haha -- damn, caught out. :doh: :bugeye:
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:)
It works!! Pennies slides nicely - motor doesn't have an issue with the atx supply - it could happily push a stack of coins I think. Atx supply is also powering the LED backdrop. I only cobbled the back drop together earlier this afternoon so lots more work to do... But you get the idea.
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Cor...you got a lot of money in your house... :lol:
Nice job Chris and well done.... :dremel:
I guess you have a shute sytem to make now for dropping the coins in and out...?
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Yes, absolutely! In reality the project has only just started! I've now got to mount the back board and front Perspex glass to the back board to stop the pennies falling out. Then most penny pushers have some interesting way of making the coins fall down more randomly - normally random pins inserted so they hit the pins on the way down and bounce around. I'll probably end up doing that. I did consider putting a small motor right in the centre of the back board so if coins hit this, they would be thrown about a bit - not sure how well that would work.
A really important question for all your creative type out there... A prize for a good name/title for the machine. My children are called jack and Ella so perhaps something incorporating that? Or even Raynerd?
Any suggestions welcome! I'm going to have a vinyl sticker made and stick this to the backboard!
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Rascal Raynerd's Rapacious Random Rapscallion
or
Old Codger Chris's Coin Collector
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The Rayn-Er-Shine Jack-pot Ella-mantor.
aka
The Rain-or-Shine Jackpot Eliminator
kinda fits with the windshield wiper theme, too
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Great stuff Chris. :clap: I think you've got the forum captivated with this one. I don't know how you manage to make so much progress with two small children around, but keep it up.
Ella-va Jack-pot
Gary
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Haha cheers chaps. I'm loving the names, keep them coming!! :clap:
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Raynerd's Jackpot Elavator
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Brilliant that!
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Hello again guys, been working on the pusher some more and will have pics shortly.
I was hoping to get some opinions please. I want to put an alarm on the machine so no one is tempted to tilt it and if they do, the coins will be collected in the cash box and not in the winning tray.
I can handle the sensing with an arduino and my idea is to use a solonoid to immediately lock out the winning tray but I then need to divert the coins to the cash box.
Drawing is really not a strong point, I'm terrible! However, my sketch below shows my idea.
The coins falling off the front edge are winnings and the cash box coins which the machine eats up are through the two holes at the sides but back from the front edge.
My idea is to have a sheet of mdf or Perspex (something low friction) at a very large angle. This has a divider in the middle. Coins falling off the front fall into the front tray and slide down through the trap door to the outlet wining tray. Coins falling through either of the secret holes fall into the back tray, slide down and around the corner through a hole to the cash box.
The idea is that the front winnings tray hole has a hinged flap. If the machine is shook and the alarm signals, a solonoid immediately pulls down the flap and any falling coins go over the flap and down into the cash box hole.
Too complicated? Will it work? Possible problems? Simpler ideas? ....your thoughts are welcome as always!!
(http://raynerd.co.uk/wp-content/upLoads/image7.jpg)
Chris
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I'm beginning to think you don't trust the kids, Chris. :)
Why not just bolt it to the wall.
Gary
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Funnily enough, it isn't the kids I'm worried about. I'm pretty sure it will be the first thing my brother in law does when he sees it!! I'd get a right roasting if I bolted to the wall!!
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Funnily enough, it isn't the kids I'm worried about. I'm pretty sure it will be the first thing my brother in law does when he sees it!! I'd get a right roasting if I bolted to the wall!!
Chris
If I couldn't trust my brother in law any further than that I would ban him from my property.
Cheers :beer:
Don
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Too complicated? Will it work? Possible problems? Simpler ideas? ....your thoughts are welcome as always!!
.......I'm pretty sure it will be the first thing my brother in law does when he sees it!!
Have you considered voice recognition for guffaws AND-ing that to a tilt sensor and then if positive initiating an electric shock?
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I think you are getting the wrong idea here... he won`t be interested in stealing the coins - he`ll want to do it to prove a point that playing isn`t necessary and you can just rock it to win!!
And lets face it.... when did it become mandatory to have a reason for additional madmodding!! :proj:
I want to do it for the challenge of integrating this feature - I`d just buy myself a penny pusher if I wanted one!!!! :mmr:
EDIT - my understanding is that this is a feature of commercial pushers!
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Just kidding, of course -- sometimes forget to put the laugh guy in: :lol:
Great admiration for your penny pusher, and the fun of including all the details, not to mention the priceless learning that goes along with it. One thing leads to another in projects, and one project leads to another. Ideas spring out for yourself and others. The creativity is why we're in it! :dremel: :clap:
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Why not have enough spring tension to keep the shelf in place secured by a solinoid to lock it, when it gets tilted the solinoid releases and the weight of the pennies cause them to drop the spring resets the tray locked by the solinoid.
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Hi Tom, thanks for reading. Could you possibly describe that again or in a different way. I don`t quite see what you mean .
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I would think that a spring like one of the type the shaft fits through with the two protruding ends to keep the base presure on the drop plate in the up position and return it after a drop the solenoid just keeps it in place till the tilt is trigered a simple incline ramp either spring load or just a gravity latch to catch it as it resets in the up position. The weight of the coins supply the drop energy. :coffee:
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Tom, what about a pendulum weight instead of a spring? If the hinge line goes right through the center of the panel and the pendulum is directly below the hinge line, any coins off center either side will cause it to spill when the solenoid is released. Then the pendulum re-exerts a righting force and brings the panel back to level. Solenoid latches back when panel is upright -- maybe a microswitch activation.
Once the panel dumps though, the game is over until somebody replaces lots of coins. Maybe there should be a message under the coins on the panel when it returns to level. Something suitable......
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Hi,
I thought something like a flap hinged on the front edge pulled back to say 45 degrees to divert the coins into the cash box. Perhaps put it on a timer say for 10 seconds before it flips back. The cash could also go straight into your coin counter hopper ready for change to be paid out. I've seen some simple vibration sensors that would detect the movement easily.
http://www.ebay.co.uk/itm/Vibration-Movement-Sensor-Non-Mercury-Switch-5-pieces-/141022050779?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item20d591b9db
Not to be confused with tilt switches which would require the whole thing to be tipped over before switching :bugeye:
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Pendulum in a ring works as a tilt switch. Actually a plumb bob on a bit of flexible cable.
Very fine flexible multi-strand cable can be had as bead stringing wire in a crafts store. Solder this into a drilled ball bearing and make your ring as close tolerance to that as you want for sensitivity. Sensitivity can be adjusted by raising or lowering the ball in the fixed ring.
These could be an input to your Arduino.
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Vsteam same idea as me but I thought the tilt switch would have a 45 degree angle that way the sensitivity could be set by raising or lowering the ring and as far as weight versus spring either one would work. Although the weight / counterbalance can be more finetuned wheras the spring is constant.
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Hi Chaps...
just a bit of an update. I`ve not been in much so have been working on the code side for the change machine I`m building into it.
Purchased a 10p hopper and connected that to an arduino:
Then I purchased a coin acceptor off ebay and connected that to an arduino:
Next step is to make the hopper and coin acceptor talk to each other!
I`ve also built in some genuine coin shoots which also checks the coins are the correct ones! Pictures to follow.
Chris
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Wow, this is going to be the real thing...... :clap:
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Gets even better Chris!
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Ohhhhh the sweet smell of success!! After 2 weeks, the code is very nearly there. I have a lot more to do in terms of some additional features but proof of concept is there!!! It works.
So the coin acceptor is going to go at the top of the machine and it will dispence coins into the win tray.
Thanks to people who have helped via email, pm and even facebook! Thank you,
I don't get a lot of time in my workshop but writing this code has sucked up a lot of shop time so back to building it now!
Chris
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Painted a first coat on the case - arcade red. Fitted pink car stereo although this will be covered, speaker, coin selector and all the electric are in and now sorted!
Lots more to do but a good next step...
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Bit more..,,
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Looks like the real thing! :thumbup: :clap:
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Looking good, Chris. :clap:
I see you went with the name I suggested. I claim my free prize. You can pop the royalty cheque in the post if you like. Only joking. Keep up the good work, you're inspiring the next generation of engineers here.
Gary
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Hi Chris , looking good , I bet you will have a house full once word gets out about it .................... You have made a lovely job of it , very impressed :clap:
Cheers Mick.
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Hi guys. Thanks for your kind comments.
GaryM forgot I'd taken the stereo cover (ugly and not flush with the cabinet yet) - I was going to do the grand unveil of the name when I get the vinyl printed for on the back drop !!
The plan now is to get the coin box tipping function working - an extra part of the game and then really tidy it up and finish it.
Chris
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Once again, weeks and weeks pass with only short spells on this machine. In all honesty, I've had enough now and just want it finished so I can get on with some metal work. Anyway, here is the coin splash feature I designed. It is by no means perfect but the concept works and admittedly I expected this to be a complete disaster. Thoughts, opinions and suggestions welcome.
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Never seen one like that Chris, great idea and it works well! The whole thing is brilliant.