Help with LED chaser circuit expanded with relays..

[mark1905]

Hello all..

I have a project that I would love some help with. It's for a costume.

What I'm trying to do is use a simple 10 LED chaser circuit, but use the outputs of the IC chip to fire off individual 9v relays. I need each channel to light 16 LEDs at once. I think that this would be the best way to achieve my goal.

This was my logistical plan of doing it:

I found this 10 LED chaser kit for $7: LED CHASER KIT | AllElectronics.com

I was going to use one of these 9v relays for each channel: 9V DPDT MINI-RELAY | AllElectronics.com

Am I on the right track so far? My question starts coming with the best way to wire it all up. I'm assuming all in parallel, correct? How should I install the resistor? Should I use one big resistor at the beginning, or should I use a smaller resistor for each individual LED?

Any and all help through this project is GREATLY appreciated!!

 

[Reloadron]

Most LED sequencer circuits like this use a 4015 counter driven by a 555 clock circuit similar to the attached drawing. Unfortunately for your relay I couldn't find coil resistance or current but most relays like this typically have a DC coil resistance of between 200 & 300 Ohms and draw between 30 and 45 to 50 mA.

If that holds true you will want to come off your LED board using transistors to drive the relays. Also, though the 4017 counter sequentially goes logic high on clock pulses you need to make sure that is the case for the counter used on the board. Anyway, if the LED sequence goes high I wopuld think about using transistors like the 2N3904 or 2N2222 to drive the relays and place snubber diodes across the relays.

Another option would be to just use N channel MOSFETS driven off the board directly and skip the relays all together.

If we estimate each LED at 20 mA each bundle of 16 will draw 320 mA and the entire matrix as you describe it would draw about 3.2 amps! You gonna need a big battery!

If they are in parallel then each LED should have its own series resistor.

Ron

 

[mark1905]

Time to re-address this..

So.. I think that I'm going to go the n-channel MOSFET route as I've been told that is a better solution.

I have no experience using them though.. could anyone provide a little assistance?

Still looking at driving 20 LEDs per channel off of that same circuit board.