Programming

[gerthworm]

Not sure exactly how cheap you're looking, but....

Raspberry-PI based robot, programmable in Java:
https://www.dexterindustries.com/gopigo/
https://www.dexterindustries.com/gopigo-and-java/


Arduino-based (not java, but usually cheaper):

Sparkfun sells a decent kit based around arduino:
https://www.sparkfun.com/products/13166

There's also some stuff on Banggood - looks like you'd have to get the major components separately, but you might be able to pull something together:

http://www.banggood.com/4WD-Smart-Ro...l?rmmds=search Plus http://www.banggood.com/2-Channel-Mo...l?rmmds=search Plus your own Arduino plus a few batteries?


Full disclosure, I have not used any of these personally, they are just things I have found or knew about.

[dirtbikerxz]

I know this isn't super cheap, but if you have access to an extra set of frc control system parts, or want to use the set you have until you need to put them on the competition bot, you can build a mini frc bot. Here is the CAD LINK to the mini bot we built. Since it uses the full frc control system, programmers are able to learn in the environment that they will be working in.

We built the bot out of this PLASTIC 1x2 Versaframe Stock which makes it really light, and super easy to carry around by just one person. Instead of using an FRC battery, we found a 12 dollar battery on amazon thats like half the size. The drive motors are just a 775pro on a versaplanetary, with 3in colson wheels. Another benefit of a system like this is that the addition of sensors, manipulators, and other accessories is relatively easy. Currently we built a very simple flywheel shooter, that we mounted on the bot to learn how to program vision

[Tom Line]

I suggest taking a look at the CTRE Hero. It's a great replacement for a RoboRIO at a much lower price point.

http://www.ctr-electronics.com/control-system/hro.html

[jajabinx124]

Originally Posted by gerthworm

Sparkfun sells a decent kit based around arduino:
https://www.sparkfun.com/products/13166

Sparkfun also has pretty good videos and tutorials on youtube about the products they sell.

[AmoryG]

My team bought a few Arduino cars from amazon that have worked well for us:
https://www.amazon.com/Elegoo-Four-w.../dp/B01DPH0SWY

It's $70 but that's pretty cheap compared to similar kits. The kit includes code and parts to build a car that can track lines with line sensing modules, can avoid obstacles with a ultrasonic distance sensor mounted on a servo, and can be controlled with a remote/IR receiver or phone/bluetooth module.

You write Arduino code in C++ not Java, but it's actually pretty simple and teaches you concepts that you can carry over to the code you'll be writing for your competition bot. Even if the car doesn't end up working out, the parts such as the dc motors, motor controller, sensors, Arduino, jumper wires, li-ion batteries and the charger can be used for any Arduino based project. Most of the parts are generic and replaceable in case any of them get damaged.

The big issues I have with this kit is with the instructions and code itself. The instructions while simple, aren't the best quality. They were originally written in Chinese I think and the translators didn't always do a great job. There are a few errors and the instructors/pictures aren't always consistent. You probably will end up making a few mistakes if you aren't careful, but I wouldn't necessarily consider that a completely bad thing since it makes your students think about the process and gives them experience debugging and fixing mistakes that will likely happen on your competition bot. The code that comes with the kit doesn't always work right out of the box and may require some tweaking. But since it's Arduino there are many coding samples you can find on the web that you can use instead if you prefer that.