The Shop > Electronics & IC Programing
PIC Project 16f887 - Binary Clock
AdeV:
Homebrew PCBs.... now that's interesting stuff. I've looked a few times at the various kits that are available, but I've always been put off by not actually having a specific project to do. As it happens, I have a large MicroMat PCB drilling rig here at the shed, but it's in a state of some dilapidation, and hasn't been used in many years (at least 10). It's tempting to try to make it work again, as it would make a dandy CNC router; and, of course, well able to drill PCBs...
I know what you mean about LEDs; personally, I'd have used strip board rather than the plain board you've used; at least you can solder the components directly to some copper then, which allows you to fix everything down & doesn't rely on too many hand-wired connections. For your application, you may want to look at using wire-wrap kit instead of soldering everything? That also gets you out of having to make a PCB...
raynerd:
Hi AdeV - thanks for the info. I have got some strip board but I`ve got it in my head that I want to try a PCB via photosensitive PCB and etching. The UV LEDs to make a UV exposure box, x200, 395-400nm, 3000mdc are on their way from China as we speak. :ddb: :ddb: Infact, I`ve been waiting for a week now so hopefully within the next week or so they will be here and then it is time to start. I`ve ordered 200 as I said and talking to my mate, I think it will be best if I stuff all 200 onto one board and have them quite intense so there is plenty of overlap and hopefully a fairly even lighting. I was going to run them off a laptop charger, 19v, 3A in strings of about 4. I am in the process of making a box and I`ve even started programming a PIC using my binary clock code to make a timer however I mislead myself into thinking that turning them on via the PIC was going to be a very straight forward affair. Apparently it is, with some darlington transistors (on order as well) but I`m not so sure! I`m still learning and I`m taking it in as quick as possible but the electronics is lagging behind the progression in my coding!
AdeV:
--- Quote from: craynerd on February 18, 2010, 06:51:11 PM ---Hi AdeV - thanks for the info. I have got some strip board but I`ve got it in my head that I want to try a PCB via photosensitive PCB and etching.
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Quite right too, it's the MadModder way :dremel: :nrocks:
--- Quote ---The UV LEDs to make a UV exposure box, x200, 395-400nm, 3000mdc are on their way from China as we speak. :ddb: :ddb: Infact, I`ve been waiting for a week now so hopefully within the next week or so they will be here and then it is time to start. I`ve ordered 200 as I said and talking to my mate, I think it will be best if I stuff all 200 onto one board and have them quite intense so there is plenty of overlap and hopefully a fairly even lighting. I was going to run them off a laptop charger, 19v, 3A in strings of about 4. I am in the process of making a box and I`ve even started programming a PIC using my binary clock code to make a timer however I mislead myself into thinking that turning them on via the PIC was going to be a very straight forward affair. Apparently it is, with some darlington transistors (on order as well) but I`m not so sure! I`m still learning and I`m taking it in as quick as possible but the electronics is lagging behind the progression in my coding!
--- End quote ---
Yeah, my electronics skills are a bit feeble too, although I'm trying to learn (as well as learning to machine, to weld, embedded processors, car suspension design... must be an age thing). However, rather than a PIC timer, I wonder if it wouldn't be easier to just make a dead simple 555-based timer with a calibrated potentiometer? Hmm, maybe not madmodderish enough ;)
For switching, consider using a relay (nice click-click effect, saves you adding a speaker & some extra code!); got to be easier than fiddling with high-power transistors?
raynerd:
AdeV - your probably right about the 555timer but I don`t have a single clue about them, I`ve heard about them and seen books purely based on circuits involving them but not any idea how they run. The beauty of the PIC is that I can get a bit of code creep in there and since I already have a clock based code I`ve wrote, it is a very straight forward adaptation to make it function as a timer. With a keypad and lcd I could even have it running so that you input and exact time length with a display showing how long is left.
Regarding the relay, that was the route I first took but then found out that it then involved transistors and diodes to actually turn the relay or your in risk of blowing up the PIC! I believe using TIP120 darlington transistor I`ll only need a small resistor between the pic and the TIP120 and it will be fairly straight forward.
AdeV:
--- Quote from: craynerd on February 18, 2010, 07:16:24 PM ---AdeV - your probably right about the 555timer but I don`t have a single clue about them, I`ve heard about them and seen books purely based on circuits involving them but not any idea how they run.
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555's are wonderfully simple - it would be worth getting to know them a little, even if you don't use them very often. I believe the technical term is, they are an astable multivibrator - which, as far as I can tell, just means it flips states continuously. You set the timing with a simple capacitor/resistor combo (one of each - plus a variable resistor if you want variable timing), and that's pretty much all there is to it. Maybe a reset button too, and an on/off switch...
--- Quote ---The beauty of the PIC is that I can get a bit of code creep in there and since I already have a clock based code I`ve wrote, it is a very straight forward adaptation to make it function as a timer. With a keypad and lcd I could even have it running so that you input and exact time length with a display showing how long is left.
--- End quote ---
I hear you there. Although I've not done any more experimenting with my Arduino of late, I was seriously impressed with it when I was playing. I'm sure the PIC is pretty similar.
--- Quote ---Regarding the relay, that was the route I first took but then found out that it then involved transistors and diodes to actually turn the relay or your in risk of blowing up the PIC! I believe using TIP120 darlington transistor I`ll only need a small resistor between the pic and the TIP120 and it will be fairly straight forward.
--- End quote ---
Hmm - you should be able to get a 5v DC relay which will drive directly from the PIC. You do need the diode in parallel with the relay to prevent back EMF from frying the PIC when the relay is deactivated; a transistor would make for an additional safety net, but shouldn't be a requirement...
That said, once you've got the transistor in there, it may as well replace the relay! Just don't forget the clicker... (speaker on a PWM output should be fine) :)
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