Transponder & Discharger

Personal transponder

AMBrc system allows you to use an unlimited number of transponders. As each AMBrc transponder has a unique number.

So this is nice. Now you get your own and dont have to borrow on for each race. This could seem stupid, but you want it to be connected right and so on. The cost is only 500:- SEK
The casing is a bit big and clumsy, but they are used for like 1:5 cars as well and then the size does not matter that much. But we run the Mini-Z so size matters...
Used a sidecutter to remove the outer casing.
I used a "sandpaper" to take of all the edges. I stoped here, but I think you can take it down alot more.


Sometimes I change batterys even though they are not empty, so I want to discharge them befor I start to charge them again.
Until now I used a lightbulb, but it's to fragile to have in a toolbox. ?
Anyway, this is my solution to the problem. I 3 parallelled resistors, 2 of them is effectresistors that take all the "beating", and the third one is just there to save the lightdiodes.

This configuration is made to use on 4*1.2V serial conected batterys with a maximum current at 1800mA

One effect resistor at 4.7 ohm.
One effect resistor at 10 ohm.
And the last one is at 150 ohm, that is connected to the diodes.
My first ide was to have the two effect resistors separat so I could switch between them, they have diffrent resistance so if I picked the one with 4,7 ohm the batterys would discharge faster than if I connected the one on 10 ohm.

The cooling plate is from an old 486 computer CPU. It's there so the effect resistors can take more watt/power.