Rear Foglamp Controller
 

After getting my rear fog-lamp installed a few weeks back, I got the itch to make it do more than just turn off and on when you pushed the button, and I got a few cheap and simple microcontrollers that would have a few spare IO lines even after I did just the simple push button, so what I did, was made a controller that does Pulse Width Modulation on the power line of the lamp.

I wanted a bit more than the basic setup, I connected an IO line to each of the parking, reverse, and brake lights, so that I could duty cycle the lamp depending on the situation:

Here's the before picture:

And here's after, which the parking lights on:
Lamp @ 25% power

And here'swith the brake on:
Lamp @ 50% power

And here's the override with the dash button turned on:
Lamp @ 100% power

Here's a picture of the controller box in the trunk just before installation:

The trunks got all the innards pulled out so I could run the power and control + lamp lines to the dash button, you might pick out the brightly colored wires running from left to right, and the vampire clips/wire taps next to the brake/revers lamp holders:

Here's a pic of the rear wiring running between the seat and the door channel (with the molding and the seat removed)

nifty

was the fog lamp expensive and hard to wire/install?

And heres a picture of the front fuse box, where I tapped in for power, and ran the switch and switch lamp lines up to the dash.

I tapped in to power from the 'cigar' fuse line, Since I don't plan on putting much on this line, and it's rated for 15A.. The rear bulb and control box only draws about 1A at full power.

p.s. I soldered the bright wires together afterwards where they were taped together ;)

Here's a picture of the control unit circuit board outside of the box :

Here's a picture of the back of the circuit board, please excuse the burning and scarring on this board. I had originally used this board for a different purpse, and pulled everything off quickly with my 100W soldering iron ;)

Here's a picture of the switch on the dash.... Whoops, no picture of this yet..

It's the two part Lamp/DCS switch that I ordered from CanZoomer. It's illumination is powered from the rear lamp, so that it shows up at the same relative brightness level as the rear fog lamp, so it's a neat indicator. I can actually tell when my brake lights come on now.

This should be in the new DIY forum. Great work

The fog lamp originally came from Canzoomer, and it's listed on his price list for US$89? I didn't get the complete kit, because I didn't think it would do all this, and it was more than $200.

It took me about 2-3 hours to do all the circuit board design, another 3 hours to build the board, and probably about 5 hours to write the software for the microcontroller, since my partner is the microcontroller expert, I needed a small project to raise my awareness of programming microcontrollers.

The total cost of the parts for the controller ran somewhere around $15, with me re-using some old computer connectors I had around, and about half of that cost being the wiring from the trunk to the fusebox/switch plus the wire taps, plus the two-way switch (about $32? also from CanZoomer).

So, all told, about 10 hours, plus $150 and I have a very unique and functional rear fog light, which doubles as a low running lamp, and brake lamp, that automatically comes on in reverse, or when I push the override button.. ;)

OverLOAD

Wow!
 

That is amazing.

I am humbled....I bought the lamp and the two-part switch from 'Zoomer, but I thought cutting the HOLE was the hard part! I just installed it, tapped into the rear light circuit so it would be always on (unless switched off) then decided it was too bright with the stock bulb, and put some L.E.D's in instead....

You take on the problem is awesome, and I really like the indicator light being on the same circuit, hence the same relative output! Brilliant!!

S

Have you written or do you plan to write a simple DIY on setting up the rear Fog via the on/off switch. I assume a fuse and and switch will need to be installed?

Nope, I didn't do this, presume that you mean StealtTL...

I pulled power off the post-fuse side of the drivers door side fuse box, so it's already fused, plus if you look at the picture of the top of the circuit board, you'll see a honking big glass tube fuse, hard to believe that was the smallest fust I could get. Like $1.50 from radio shack for two holders, I put a 3.5A fuse in it and fuses from local auto store are dirt cheap, like $0.50 for 5..

The wiring for the switch was easy, but still no pics of that yet either, I'll get out into the garage tomorrow and post the rest of the shots later, ;)

OverLOAD

Here's a picture of the switch, with the parking lights on:

And here's the pic with the brake on:

And here's with the 100% switch override/reverse on:

Here's the picture of the wiring for the switch:

The wiring goes from the bottom, like this: Lamp power, Ground, ground, upper switch, lower switch.

I wired the two grounds together with my green wire, the blue wire is the power for the lamp connected to the bottom pin, and the yellow wire goes to the on contact for the upper switch to turn the override on.

This leaves me one unused position on the switch, where it currently says DCS off..

OverLOAD

It looks very nice. I think I will P/M you about this.

Damn OverLOAD, that is freakin AWESOME. You are DA MAN, I'm impressed - that's EXACTLY what I ultimately wanted to do with my rear fog, which is why I haven't hooked it up yet. You've got MY nomination for the "Coolest mod of the year" for this one!

A PM is on the way to you... :D

Just noticed something else: You left your other DSC Off switch in place. Is it still doing the DSC? If so, why didn't you use the new switch and free up a switch position? Inquiring minds wanta know... ;)

You know how hard those switches are to get out? Dang... Plus, the normal DCS OFF switch has regular illumination. Plus I figured that I might come up with a use for the other switch some time down the road and I might regret tying the two together.

I didn't even pull the other switch out, I don't know if the harness is the same, but it probably is, I suppose you could use it for that if you preferred.

Regards,

OverLOAD

Logical. You can always hook it up later if you need that switch position for something... and I have a feeling you will. ;)