Add Sound Effects to your R/C Car

Step 6: Body Wiring

LED's are polarized devices.  The shorter lead of the LED is the cathode, and the longer lead is the anode;




The mnemonic I use is that getting 'less lead' is a negative thing, hence it's the cathode.  Getting more lead is a positive thing, so it's the anode. All of the LED's on the body will have their cathodes (short leads) connected together, in a chain.  At the end of the chain, add a foot or so of hookup wire, this will eventually connect back to the R/C Animator;

The LED's don't share anodes, though.  Connect hookup wire to each anode separately.  Start at the end of the chain, twisting the wires together as you add each LED;



If you're connecting four LED's you'll have five wires;

• one wire that's connected to the long lead (cathode) of all the LED's.
• four wires that each connect to the short lead (anode) of a single LED.

Curl each wire around a pin header, making a 'pin header connector', and solder them together.  Important: The shared cathode wire goes on the rightmost pin.



It doesn't matter what position the other wires are in, you can even skip a pin if you'd like.  But make sure the shared cathode wire is on the rightmost position.  This is a pretty weak connector, I suggest re-enforcing it with some hot glue. 

Here's the circuit, too;