DIY Sequential Taillights for approx $20

[brettsimons]

Very true! This is why two brains are better than one haha but I have a lot of extra arctic silver thermal paste at home so I'll probably end up attaching the resistors to the metal cover of the project box with some thermal paste to help conduct the heat but I have to say I've never used thermal paste for anything other than CPUs and their heatsinks so this should be interesting

Sent from my Galaxy Nexus using Tapatalk 2

[pkauf]

Originally Posted by sjmautoprod

Just a bulb swap with the addition of a load resistor at each inner.

Exactly like that.

Bulb swap isn't required, correct? But we've all now said the load resistor is to avoid the BCM error messages . . .?

[pkauf]

I found some cheaper load resistors at digikey - but they only have 6 ohm at 50 watts - would that work? http://www.digikey.com/product-detai...-6.0-ND/269967

[hapisok]

yes, that would work. you just don't want to be under the required wattage rating. you should never have to worry about those big boys getting hot.

[pkauf]

Originally Posted by hapisok

yes, that would work. you just don't want to be under the required wattage rating. you should never have to worry about those big boys getting hot.

Thanks, always think bigger is better, but you never know.

[Highlifeman]

Well, I didn't realize the 555 timer in the original schematic was sinking the relay, so it was actually correct that an P-type or PNP transistor would be needed if you wanted to do it with only one transistor.

Anyway, here is a couple of schematics showing how to do it with two MOSFETs or a MOSFET and an NPN transistor. All the components on the left side are the same as the original schematic in the thread. All of these components should be available locally at any Radio Shack.

I can't guarantee that the bottom one will work with those resistor values, but it should. If it doesn't work, going to a smaller resistor for the 91K should make it work. I did one with the NPN because it should be cheaper and smaller, but both may be negligible. However, I can all but guarantee the top one will work, so that may be the better choice.

Edit: Replace the 1K resistor in the top drawing with a 6 Ohm, >35W resistor to get a constant current draw from the lights. It would serve the function of the "load resistor" previously mentioned. DO NOT DO THIS WITH THE BOTTOM CIRCUIT, it will fry the transistor.

[hapisok]

awesome! thanks highlife. i'll work these on a bread board this evening. i bought a P type Mosfet last night at $10 for 1...ridiculous! even 2 N types are cheaper than a P. either how, i'll let you know how these work out.

thanks again!

[Highlifeman]

I think you've been connecting it in this manner, but make sure that the wire you cut is the positive wire going to the light. If it's the negative wire from the light this wont work at all. (I could make it work that way if needed.)

A post a ways back about how to connect it made it seem like it was using the negative lead, but looking at the pictures looks like it uses the positive lead which is how I designed my circuits.

Edit: I just realized that you could put the load resistor in place of the 1K resistor in the top schematic I posted. That would make the current go through the load resistor when the light is off but then switch to the light bulb when it comes on. This would prevent the BCM errors and not cause excess current draw. Do not do this with the circuit with the 2N2222...

[sjmautoprod]

Originally Posted by pkauf

Bulb swap isn't required, correct? But we've all now said the load resistor is to avoid the BCM error messages . . .?

Bulb swap is required and the load resistor is for the BCM errors.

Originally Posted by chef-beavis

Can you pm me details for the load resistor? Thanks! I'd even be interested in a "kit" from you for the parts if that is something you have.

I'll PM.

[pkauf]

Originally Posted by sjmautoprod

Bulb swap is required and the load resistor is for the BCM errors.

OK, now i'm really confused. You hopped on a couple pages ago and mentioned getting the same effect using LED on the inner + load resistor. Then others worked on putting a load resistor on the circuit that was the main start of this thread (with the variable resistor, relay, etc). Just so I understand, the bulb swap isn't necessary for the circuit being discussed . . . Sorry, just making sure I get the multiple thoughts going on here.

Thanks . . .

[sjmautoprod]

Yes sorry, that's correct. there are 2 subjects here.

[pkauf]

Originally Posted by sjmautoprod

Yes sorry, that's correct. there are 2 subjects here.

Jeez, i feel better. I know I half understand this stuff, but for a minute i really thought i was lost!!! Thanks . . . No big deal - this is all very interesting stuff!!!

[Muscle SS]

Originally Posted by sjmautoprod

Bulb swap is required and the load resistor is for the BCM errors.


I'll PM.

I would love a pm with the same info you sent chef beavis

[sjmautoprod]

PM sent!