Month: August 2014

Making a radio controlled tank – Part 1 – Mechanics

I’ve tried my hand – literally – at quadcopters, submarines, and RC buggies, and now its time to make a tank. Hmmm, I guess more of a tracked box but we’ll call it a tank.

While searching for information on the subject, I ran across a website describing how he had made the treads out of bike chain and acrylic, the motors were ripped from cordless drills, and the chassis was essentially adult Meccano. All of this looks to be within the realm of possibility, and has the potential for being massively over-engineered – the best way to engineer.

Continue reading Making a radio controlled tank – Part 1 – Mechanics

CRC8 – Arduino and PHP implementation

For my tank project, I’ll be sending parameters over radio to control the motors so the data packets should be checked to see if they’re valid or if the transmission was corrupted. This is a widely used concept in computing – almost every transaction comes with a checksum which lets you know whether the data that was sent is the same data that you received. If you’ve ever seen a cyclic redundancy check error on older versions of Windows, you’ve seen a bad checksum; the hard drive transmitted something that the operating system checked and found it wasn’t correct.

Data-Error-Cyclic-Redundancy-Check

EDIT

Looks like someone has beaten me to it, and created something much better. Here is an implementation which uses the built-in CRC module on the Teensy 3 to improve CRC calculation speed, and also creates 32 bit checksums.

Continue reading CRC8 – Arduino and PHP implementation

Capturing servo RC PWM signals with a Teensy 3.1

Turnigy 9X receiver without its plastic case

For my tank project I needed a failsafe should my serial radio link crap out on me, and as I had a standard RC transmitter lying around, it seemed natural to use it. After doing a bit of reading and prototyping, I managed to come up with a fast, non-blocking method of capturing the RC signals and converting them into a usable value.
Continue reading Capturing servo RC PWM signals with a Teensy 3.1