Turbo: A standalone, patchable drone and noise instrument

It has taken me a long time to make this video! Turbo is a project I started somewhere in 2015. It is a fully analogue electronic instrument that could be described as a synthesizer.

The video provides an overview of what Turbo can do, and how it sounds. It is worth listening with headphones or decent monitors. Short description below.

Turbo was originally designed to be a DIY project, I wanted it to be a ‘kit’ instrument that could be assembled with simple tools – but the project grew in size and complexity and combined with all the other things going on in my life in the last couple of years, I found it too difficult to realise this goal and decided to build a limited number myself. I planned to build 10 and have so far managed 7 – I am not sure if I will complete the last 3 at this point. They are not complicated to build but very time consuming, and I almost gave up the project a number of times over the years.

I could go on with the history, but let’s talk about the other ideas. Turbo is inspired by the guru of drone Éliane Radigue with her early recordings on the ARP2500. The idea was to capture this kind of sound in a small and portable format. Turbo generates sound with a pair of voltage controlled oscillators and a resonant state-variable voltage controlled filter. There are various preset and patchable routes to modulate sections of the instrument with each other in exotic ways. The video demonstrates some of these routes and patch possibilities so I will just provide a list of features here:

  • 2 x Voltage controlled oscillators with triangle and square wave outputs
  • State variable voltage controlled filter with resonance, low-pass and band-pass modes
  • Voltage controlled crossfading between oscillator outputs and filter modes
  • Sample and hold which samples VCO1 Triangle, and is clocked by VCO2 or an external source
  • A comparator which is set by the two VCO outputs, creates complex modulations and distortions
  • A function generator or LFO with ramp up and down controls, and ramp/pulse modes for creating slow modulations and transitions

Much of the work that has gone into Turbo has informed my current design for modular systems. I learned a lot about analogue small signal circuits, but also plenty about mechanical construction, feasibility and the limits of my own patience!! I hope you enjoy the video and welcome any comments!

Christmas Makes 01: TweeterPiTweets, An Automatic Tweeting Camera Trap for Garden Birds

This year I decided to do some making for Christmas and now the gifts are out and the surprise is over I can share them with you! I managed two projects, and it turned into a lot of work! This is the first which I called TweeterPiTweets:


You can probably guess a little about what this device does from the images – it is an automatic camera that responds to motion and then tweets the captured images. I made this project for my parents as they have a perfectly placed bird feeder on their kitchen windowsill – so the idea is to capture images of the visiting garden birds. After a little bit of tweaking I think I got this device working effectively and from the first day it is has been running we already have some impressive results!

You can view the twitter feed here: https://twitter.com/tweeterpitweets

Great pics from day 1:


Great Tit




Some notes on the build:

I made the enclosure in Cardiff FabLab, the front half is 3D printed and the back pieces are laser cut layers – I intended for there to be just two separate pieces, with a single laser cut back piece fitting in to the 3D printed front, but I underestimated the depth of the parts inside hence the extra layers.

The electronics are made up of a Raspberry Pi Zero W, a PIR sensor, a 160degree variable focus camera, a Pimoroni Wide Input Shim and a cool Rainbow LED – links are all to the Pimoroni store, I managed to get most of the parts in a pre-Christmas sale which made it quite inexpensive to build 🙂

In the end I ditched using the PIR sensor – there are some many aggravating nuances to getting it working correctly, and it turns out that infrared wavelengths don’t pass through glass so well anyway (just as a small tip though, the PIR sensor seems to work a lot better if you bypass the 5V regulator and power it directly from the Pi’s 3v3 rail, despite have a clean regulated output from the Wide Input Shim!)

It turned out that actually using the Pi Camera as a motion sensor was much much better. Gareth Halfacree (@ghalfacree on twitter and @ghalfacree on GitHub as well) has created an awesome bash script that is designed for camera trap set ups. The idea is that the camera constantly takes low-resolution images and scans for pixel changes between the latest and preceding images, if a change is detected then a high-resolution image is taken. There are a number of variables in the script that allow you to define a particular area of the image to scan for change (so you can ignore things like branches waving in the wind for example) and you can also tweak the sensitivity and thresholds for successful triggers.

I combined this script with Tweepy, a Twitter client for Python to get the final result.

I had to build this project with a pretty strict time limit which is why hardware issues haven’t been totally resolved. If you liked this post, let me know in the comments below and in the new year I will find time to upload a full tutorial 🙂