MadModder
Gallery, Projects and General => How do I?? => Topic started by: shipto on July 21, 2013, 06:06:47 AM
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I am currently working on a model carousel for my grandaughter but am scratching my head a little over control for it.
BTW before I get :worthless: I am taking pics but dont want to post any of them before I am sure I can complete the project.
anyway I am thinking ahead a little about control for it, I need to control.
speed of the motor = quite easy a pwm will do this.
music = I would like 3 or more songs played at random while it is turning
Lights = about 150 led's (not individually but in blocks) they need to blink in a random or seemingly random way as the carousel turns.
Even though i know nothing about them I am looking at arduino or pi for the controls but would gladly listen to opinions or ideas.
Thanks in advance
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You could use or build a cam timer.
(http://iforce.co.nz/i/lcxowtio.dta.jpg)
A motor turns a bunch of cams that activate an array of microswitches. It wont be perfectly random but you could maybe approximate it.
For music you might be able to solder the contacts of an MP3 or CD player to the cam timer. You can get both items pretty cheap nowadays but i'm not sure if all of them would be suitable.
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http://www.timhunkin.com/81_components.htm
This fella is one of my heroes. He makes strange amusement arcade machines. His website has some info on the stuff he uses in making them.
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There's a random-ish led flasher circuit here, which looks relatively simple. Don't know if it works, though, and your 150 leds might be a bit much for it (diagram shows 40). You could always build one, and if that's OK, another three for a total of 160 leds..
http://scdiagramwiring.blogspot.co.uk/2013/03/how-to-make-interesting-random-led.html
Andy
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How one's sordid past comes back .... :palm:
I did a random light flasher using the amplified noise from a Zener diode and stuffing it into the Analogue ( Analog for those in the USA who can't be bothered to spell it properly :lol: ) input on a PIC. Cramped the output value into 3 bits to give 8 outputs, ( there is a CMOS chip ie. a 3-line to 8-line decoder).
Not much use to you if you want to do Arduino or Raspberry Pi though. The code was in MikroC or Hi-Tech C . to a 16F886 PIC.
Worked rather well to my surprise.
I think I may still have the circuit somewhere but not sure, simple enough though.
Will have a look if you're that desperate .. :scratch:
Dave BC
Edit ... 74HC238 chip :thumbup:
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You could use or build a cam timer.
(http://iforce.co.nz/i/lcxowtio.dta.jpg)
A motor turns a bunch of cams that activate an array of microswitches. It wont be perfectly random but you could maybe approximate it.
For music you might be able to solder the contacts of an MP3 or CD player to the cam timer. You can get both items pretty cheap nowadays but i'm not sure if all of them would be suitable.
I really like this idea :thumbup: it would certainly be easier for me to understand than learning to program the arduino and i could run it from the drive motor. as you say it wouldnt be truely random but with the right gearing it would seem that way.
andyf your link also looks interesting and would take up less room than the cam idea.
Bluechip if you find the circuit I would be interested to see it but dont put yourself out it will be a while before I am ready for it.
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I'd definitely go the Arduino route.
What you want to do is trivial and with a few pointers you could have something running in an hour or two.
More importantly you can 'knock' something up that works (start by looking at one of the many bits of code that simply flashes leds) and then as your confidence grows you can add to it.
The pwm for the motor control is one command. Flashing a led consists of a delay and then changing the state of the output. There are random functions in the library you can use to get a random value back. The whole thing is just a few lines of code - I'm sure there are lots of people on here who could get you started.
But the most important thing is if you want to change something (for example the leds flash in an annoying pattern, or you want them to flash evenly or 'ripple' etc) then it's behaviour can be modified with a software change.
You could even add a MP3 board to it and play tunes from that.
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You could even add a MP3 board to it and play tunes from that.
I suspect you could fairly easily make the LEDs flash in time to the music...
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I'd go with PWM for speed control, but for the flashing lights had you thought of the fibre optic/colour changing christmas tree idea? just needs 1 halogen 12v bulb or led bulb and a handful of fibre optic plastic strands. Butchering an old tree may be a source of parts/motors
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Instead of trying to create a random LED flashing circuit how about just using individual LEDs that flash on their own? I have used them in projects rather than build a circuit to make them flash.
Like this;
http://www.ledssuperbright.com/100-3mm-flashing-led-p-253/gclid/CISYlNeVw7gCFQto7Aod8m4ABA
PWM modules are cheap so I don't try to build them either. Just lazy I guess.