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Need Help please With LED changing Colour circuit

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MonkeyMera

New Member
Please can I have some help, this is to be used in a car (12V DC). I'm not very good with this sort of thing, I'm better with car wiring.

I want to create as many colours as I can in my car, I thought of using RGB LED's because they can create loads of colours in one unit. These LED's have 4 legs, one common earth, 1 for red 1 for blue and 1 for green. I want to be able to scroll through the colours automatically, I think I have found a way of doing it (it's a bit Mickey Mouse) and I was wondering if you people could think of a better or (cheaper) smaller way of doing it. I've shown each colour as a separate LED for ease,

TR2 is a Time Delay Relay set to delay 2 seconds

TR3 is a Time Delay Relay set to delay 4 seconds

The dimmer switch is a normal touch sensitive dimmer switch (TSDS), the touch panel/switch will be removed and a normal on/off switch added in its place, the reason for doing this is if you press and hold a TSDS it goes bright then dark and so on. It takes about 4 seconds from off to full bright to off again, using this bright to dark and combining the time delays it should give me a scroll of all available colours. Also (not shown) I plan to put in a manual rotary dimmer knob for each colour (so I can select an hold a colour), this circuit will be running in parallel with this one, when the circuit that is shown bellow is switch on a relay is thrown switching off the dimmer knobs. I'm going to be controlling about 50 LED's in banks of 10.

I have never used a PIC before nor do I know how do program one, I under stand it can get quite expensive to get set-up. But if its easy to do I might look in to it if you could give me some guidance.

I applogise if the diagram isnt good, im not that good at wiring diagrams

Your help would be appreciated


Monkey



Diagram
http://www.itsnotacrime.co.uk/forums/index.php?act=Attach&type=post&id=4759
 

Nigel Goodwin

Super Moderator
Most Helpful Member
MonkeyMera said:
I have never used a PIC before nor do I know how do program one, I under stand it can get quite expensive to get set-up. But if its easy to do I might look in to it if you could give me some guidance.
PIC's are very cheap to get set-up, it's one of the reasons they are the most popular hobbiest micro-controller. You can buy a kit for a programmer for well under 20 GBP, and that's your only expense (except for whatever PIC's you buy, but those are pretty cheap anyway).

You can spend a lot of money if you want, but it's not required to program PIC's.

If you search on these forums there's a long thread about LED's in cars.
 

panic mode

Well-Known Member
did you think of using PWM instead of analog?
 

Nigel Goodwin

Super Moderator
Most Helpful Member

Nigel Goodwin

Super Moderator
Most Helpful Member
MonkeyMera said:
That tread is perfect!!! thanks :D

there's even a new small PIC now which has three PWM channels, which would be ideal.
i dont know what PWM is,
Pulse Width Modulation - an efficient way of controlling the amount of power to a device, such as a motor, light, heater etc. Basically you turn it ON and OFF rapidly, if it's ON 50% of the time, and OFF 50% of the time, it will be getting 50% power.
 

Oznog

Active Member
Driving 10 LEDs is parallel is no problem, you just have to use resistors on each one.

Be aware RGB LEDs, at least the ones I've seen, don't have a really high light output. Each color may only be 10%-20% of what you could get a single LED of that color in. But of course it's a bit harder to see the RGB mix as white when they're physically spaced apart.

Given your 12v source, you can put several LEDs of the same color in series with only one resistor per string, it's more efficient. However, this won't work with RGB leds, they can't be put in series due to their common anode or cathode.

Be aware that comon anode versus common cathode RGBs use totally different driver circuits too. I can say right now the common anode is a bit easier to drive.

PIC is the way to go. You can do lots of neat "trick" modes too.
 
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