Tag Archive: electronics

2016
02/05

Category:
Computing

TAG:




COMMENTS:
Comments Closed

Robot retro-fit

RoboRover

I got a lovely friendly yellow robot (a WowWee RoboRover, as it turns out) as a leaving present from my last school. It’s lovely. But it only goes in one direction: two tractor treads, but only one motor. My 4-year-old loves playing with it, but I can’t help but feel that we could do more…

Over the Christmas break this year, I decided the time had come (particularly in light of the advent of the Raspberry Pi Zero) to upgrade the cute little critter. Tamiya 70097 Today, I finished phase 1 (it sounds better in my head if I pretend I have some kind of structured plan), and proved that the motor unit I’ve picked out will fit in the chassis of the Roborover. It’s a Tamiya 70097 geared twin motor unit, from a range of remote control vehicles (promising start…) and was, itself, rather fun to put together.

I’ve also bought an infra-red receiver, a TSOP38238, to hopefully make use of an old r/c helicopter handset, so that’s this weekend’s challenge; let’s call it phase 2 🙂

Phase 3 will be modifying the chassis to be be able to get the motor unit embedded and running. Ideally, it’ll allow me to use PWM to accurately control the robot speed and direction from the r/c handset stick.

Phase 4 will be re-fitting the body back on top (with modified eye LEDs – I’m hoping to get colour-changing ones in there that will be controlled by the spare stick on the r/c handset.

Phase 5 will be seeing (a) if my 4-year-old is still the same age(!), and (b) whether she likes it!

Wish me luck 🙂

2015
10/29

Category:
Computing

TAG:


COMMENTS:
Comments Closed

Raspberry Pi theremin

This was the supposed to be just a quick project to fill some time while waiting on an eBay purchase from China. I had been building up parts ready to build a simple Raspberry Pi-powered robot (inspired by articles in both Linux Format and The MagPi magazines).

The distance sensor is an HC-SR04, only a couple of quid on eBay, and I then found a simple guide on ModMyPi showing how to wire the sensor into a Raspberry Pi and read the distance in Python.

It being half-term, I had ordered the required resistors and was delighted at how easily the code work. “Fabulous!” I said to myself, “Now I just need to make it round the distance to, say, the nearest 5cm and then play a tone from there.”

How wrong can one statement be?!

After a good two days of intermittent playing, I have managed to get *something* working, basing my theremin on Zulko’s Pianoputer as I simply couldn’t find an easy way to just get Python to play a pitched tone. His code was set to use a keyboard, mine now reads the distance from the HC-SR04 and plays the relevant sound from there. In place of his “bowl.wav” I’ve grabbed (and trimmmed, and down-sampled) a clarinet sample from freesound.org and use that as my base sound, which Zulko’s code then down/up-samples to make the various pitches required, at startup.

So yes, it’s a little clunky. And yes, it can take a while to start up and transpose the various samples.

But I’m a happy geek – I built my own personal theremin!