RGB LED driver, Any comments?

[paxmowa]

hmmm, I figure there's also the voltage drop over the transistors. about 0.6 volt each.

So the resistors for blue and green should be 10 ohm and for the red should be something like 82 ohm.

Getting there... slowly, but getting there none the less.

Steven

[charudatt]

Hello PAX / Other,

I am trying a very similar project in which I send a byte (actually 3 bytes for R-G-B) information for each of the color LED via the RS232 Port to form a Colour Combination.

I am plannig to go about using 3 12F629 for each of the LED's. I am having some problem of communicating the PIC's with the RS232.

Can anyone share some code samples for the RGB LED out here ?

regards

[peu]

Im using a single 12F683 (or 12F675) for controlling the RGB channels and I still have space for an extra potentiometer (for sweep speed) and 2 buttons.



For PWMing I use PWM instead HPWM, of course if you have 3 HPWM is a little easier, but not much...

you share a common ground and use a 7805 regulator for the pic, then you can power the regulator and the leds with any value from 5-24V (+ after the resistors)

I drive luxeon leds without problem

Have fun

[ERIK]

Hey Peu, I'm working on pretty much the same thing with a 12F675 PWMing to 3 Mosfets. Everything is working well except I'm finding when I PWM from GP2 and GP4 the MOSFETs don't really pulse they pretty much just stay on, or switch off when the cycle gets low enough. I'm not sure why, I've poked the ANSEL and CMCON, but it seems maybe the output voltage on those pins is a little different or something. Anyone have any ideas what might be going on? I see you are driving your green channel with GP2, does that work fine for you?

[peu]

Hey Peu, I'm working on pretty much the same thing with a 12F675 PWMing to 3 Mosfets. Everything is working well except I'm finding when I PWM from GP2 and GP4 the MOSFETs don't really pulse they pretty much just stay on, or switch off when the cycle gets low enough. I'm not sure why, I've poked the ANSEL and CMCON, but it seems maybe the output voltage on those pins is a little different or something. Anyone have any ideas what might be going on? I see you are driving your green channel with GP2, does that work fine for you?

I used this header in a previous version that used gpio.0 as an adc input and 1,2 and 4 as the pwm channels

@ device pic12F683, intrc_osc_noclkout, wdt_on, mclr_off, protect_off
@ device INTRC_OSC_NOCLKOUT
DEFINE OSC 4

trisio =%00000001
ansel =%00000001 'analog off except gpio.0
cmcon0 =%00000111 'Comparators Off
pasos con 16
ciclos con 10
conta var byte
puerto var byte


and this is the routine I use for the led brightness increase:

for conta=0 to 255 step pasos 'Rise routine
pwm puerto, conta, ciclos ; puerto is the port to be used
next conta
high puerto ; after it reached the top brightness, set port high
return


you can use the same routine for decreasing, just change the for next and put a LOW after the loop instead of the high.

hope it helps


Pablo

[KD6OJI]

Try using a 1K pull down from the gate to ground on your MOSFET's. I have found that sometimes they get a little flaky with PWM and the 1K seems to make a huge difference.

[ERIK]

Ya did put some 1K's on and found the same thing, that it all worked perfectly. I should've come back to this post with that. Strange that I haven't seen any mention of doing that anywhere else.

[eduman]

I am a new user.Where is the asm or hex code for this cicuit.
Thank you very much.

[skimask]

I am a new user.Where is the asm or hex code for this cicuit.
Thank you very much.

You haven't written it yet!

[eduman]

Sorry,
I don't understand.

[skimask]

Sorry,
I don't understand.

People spend a lot of time learning, building, writing, testing, researching, and repeating that same process until they get the result they are looking for.

I (as well as many others) would be more than happy to write the code to fit your application, design a circuit, build a board, and I'll even hand deliver it to your house/business/whatever...for the right price!!!
Or maybe you could just learn it yourself...

Post your idea for a circuit, and some code to go along with it. We can help you iron out problems.
There's a lot of people around here that would be more than willing to help you out.
But, as for me (and most others), I'm not going to do it for nothing.
One hand washes the other...
You wash my back, I'll wash yours...
Do unto others...
blah blah blah
Get the picture now?