Fighting Buggy - Part 6 (Electronics)

Now that I've finished the rear and front axles, it's time to put them all together and install the electronics. 

Some parts called for precise measurements. Thanks to Qoo10, I was able to find a digital caliper for a good price. (The Tamiya caliper cost S$60. And it isn't even digital!)

Similar parts can differ in the tiniest ways. I had to take out washers that I installed earlier because I wrongly used the 4mm instead of the 3mm-wide ones.

Front wheel axles to be assembled onto the chassis 

This is the front member, which enables me to control the direction of the turn...

...via shafts connected to the wheel axles. 

The front bumper

The instructions actually called for a 6.6V Tamiya "M-size" battery. But if you don't fix the brackets, the chassis comfortably fits a standard 7.2V stick. I got an Intellect NiMH one with a 4600mAh charge.

The Electronic Speed Control (ESC). This acts as the gateway between the radio signal, the battery, and the motor. Mine's a Tamiya TEU-105BK meant for brushed motors that are 25 turns or more. (The stock Johnson motor is a 27T brushed.) Nothing fancy, but it does its job. There's a Battery Eliminator Circuit (BEC) in it that transforms my 7.2V battery down to a 6V output.

If the motor is the heart of the buggy, the servo is the nerve center. The servo controls the movements of the car. In bigger and more complex vehicles like trucks and planes you can have multiple servos all connected to each other. The fighting buggy just has one, so it's as basic as it gets. 

I didn't know much about servos when I bought this (actually, I still don't), but it seems to have been a decent choice. It's a digital coreless Futaba servo. It turns pretty fast at 6V (which is the output of my ESC) at 0.10 sec/60 degrees. It also packs a decent amount of force in the turn at 8.7 kgf/cm. 

Powerful servos, especially those with metal gears in them like my Futaba, need strong servo horns. I got the standard Tamiya aluminium horn upgrade.

Here're my electronics all connected. The battery is hooked up to the ESC, which connects to the motor and receiver (and is activated by the on/off switch). The radio receiver, in turn, is hooked up to the servo.

Some double-sided tape sticks the electronics onto the top plate that'll go on the chassis. Time to test the sucker!

Looks like the servo's working! It's quite a thrill watching the shafts move left and right as I turn the wheel on my radio control. The clicking sound made by the Futaba as I turn makes it seem like I'm a master robot overlord....

And the engine revs away. Now to attach the wheels and try it out on the ground!