How to: make mechanical models with SketchUp and Sketchy Physics

I’m working on a new project, slowly but surely. In the process, I’m learning how to use a physics plugin for SketchUp called Sketchy Physics. To be honest it’s kind of crap, but once you get your head around its quirks it is pretty useful too. I’m documenting my learning process with an ongoing series of tutorials:

DIY synth-making workshops starting soon!

I’ve just opened bookings for another round of DIY synth-making workshops.


The first class I am going to offer this year is to build your own Nebulophone: a super sweet stylus synth from US outfit Bleep Labs. I built my first Nebulophone a year ago and I still use it all the time: it is heaps of fun to play and packs a lot of punch for its size. It has a lot of cool features like an LFO, analogue vactrol filter, arpegiator and a sequencer: which basically means you can make heaps of different noises from lush melodies to full-on audio devastation.

Tools, parts, and instruction will be provided – no experience necessary. The class takes about 2.5 hours, and I keep the numbers down to 5 or 6 students at a time so you will get plenty of personal attention. The class will give you a good introduction to the basic theoretical and practical elements of electronics, without overloading you with the boring and confusing details.

Cost is $95+b.f. which is less than what it would cost to purchase a finished Nebulophone, and you get a class thrown in for free!


You can book your spot in the class here. I’ll be adding more dates as the classes fill up so let me know if there’s a specific date/time that works for you and I’ll try to work in with you.

The first round of classes will be in Wellington, NZ, but I’m heading over to Australia later in the year so let me know if you want me to come to your town. I’m also toying with the idea of doing a few workshops in Whanganui and Auckland, if there’s interest.

Other classes for 2012

If you want to take a class but the Nebulophone doesn’t float your boat, I am currently scouting for other options, like maybe the Autonomous Bassline Generator. Or maybe you’d like to build you own little battery powered guitar amp. I’m open to suggestions!

If you’ve got some kids that might like to learn about electronics, I’m looking at running a Klackerlaken workshop soon too. Drop me a line if you’re interested, I reckon it’s going to be a blast!


If you haven’t seen them, check the sweet videos Lekrmoi made about the workshops last year.

How to: build your own MIDI controller

MIDI controllers are a popular DIY project as they are relatively basic: a suite of buttons and knobs wired to some kind of controller and mounted in a case. Instructables user Fuzzy Wobble has put together a fantastic tutorial on how to build your own MIDI controller, including good tips on laser-cutting your enclosures and front panels.

Holidays hiatus + DIY Synth classes for 2012

It’s been a great year for Rich Decibels. I’ve been flat out like a lizard drinking, and now it’s time to catch a breath. I’m taking a break over summer, but the classes will be back again from about March.

Introducing a whole swag of people to the delights of DIY synth building has been a blast, and I’m really looking forward to meeting more of you geeks-in-waiting next year. I’m planning to take this show on the road so if you are anywhere in NZ or Aus and you’re interested in learning about electronics and audio and DIY, drop me a line ( and I’ll let you know when bookings are open again.

For more info on the classes see my previous posts on the topic.

Thanks for your support this year!

How-to: design a laser-cut project box

Here’s a write-up on how I use SketchUp and Inkscape to model my DIY electronics projects in 3D and then design laser-cut acrylic enclosures for them.


So this week I finished the first edition of something I’ve been messing around with for the past few weeks: the Exenterator. It’s an oscillator that can be gated by an incoming audio signal. Click here to read more »

Nebulophone workshops for November

This round of workshops sold out pretty quickly, so I’ve opened up bookings for another 2 classes in November. If you’ve been thinking about a class but didn’t get a chance to sign up before I sold out, make your booking here ASAP. Thanks ladies and dudes! Tell your friends!

P.S. here’s another LEKRMOI video of some good people enjoying a workshop last week:

How-to: laser-engraving and filling technique

Here’s a quick tutorial I wrote on how I finish the laser-engraved labels on my project enclosures.

Rich Decibels + LEKRMOI + Bleep Labs

The kits arrived from Bleep Labs this week and LEKRMOI came round to film me assembling the first one. If you want a Nebulophone you can sign up to take a class to build your own, or buy a finished one direct from Bleep Labs.

Rich Decibels presents the inaugural Bleep Labs workshop

I’m currently seeking expressions of interest for a series of hands-on audio electronics workshops. Update: due to more than 50 people getting in touch (thanks people!) the classes are now full steam ahead. Read on for booking information.

I’ve teamed up with US outfit Bleep Labs to bring you two very cool projects: the Nebulophone and PicoPaso.

The workshops are starting in September and will be held at my new workspace in the Digital Fabrication Council HQ in Wellington. Tools, parts, and instruction will be provided – no experience necessary. Cost is $50+b.f. for the PicoPaso project and $90+b.f. for the Nebulophone. That’s less than what it would cost to purchase a finished Nebulophone, and you get a class thrown in for free!

The PicoPaso is a quick build, so the class will only take an hour or two. The Nebulophone is a bit bigger so you’re looking at 2-3 hours.

The booking system is now online: go here to book for the Nebulophone class and here for PicoPaso.

Any questions, hit me up in the comments or email me

Brainwave Disruptor

I made a brainwave entrainment device. Details on the Ponoko blog.

Arduino code snippets

This week I’ve been working on an interesting project with an Arduino at it’s core. The design is for the Briefcase Project, an exhibition which is opening in Wellington on August 8th. I’ll share more details closer to the date, but for now here are some little code snippets that I’ve found really useful, and maybe not so well documented elsewhere. Click here to read more »

Low-pass dirt filter

This week I boxed up the filter I’ve been working on in this custom made case (thanks Ponoko). I’m really happy with it, it sounds good and now it looks good too. Sound samples to come – it sounds great with guitar as well as your typical synthy application.

Here’s the finalised schematic, layout, and gutshots.

Update: I’ve just sold this one so get in touch if you’d like me to build you another.

Update: I’ve used this project as an example for a tutorial I wrote on the Ponoko forum

Filter with LFO

I’ve been playing around with filters lately, especially the popular WSG resonant low-pass filter. It’s a really simple build and is ideal for putting a bit of warmth into the harsh square waves of my logic-based synths.

I did a quick experiment today, adding a home-brew vactrol to the cut-off pot, to make a junky LFO. Here’s a schematic, if you’re interested. You can hear it in this demo, where I’ve used the sinister tone generator as a source. There’s plenty more work to do on it yet but it’s pretty fun just as is.

Sinister Tone Generator

Rich Decibels Sinister Tone Generator

Here’s something I made for the Concerned Citizens exhibition opening this weekend in Wellington. It’s a bass drone synth with two pairs of heterodyning oscillators. Click here to read more »


I introduced my version of the common LM386 guitar amp today over at the Ponoko blog. Here’s some more details for those interested in duplicating my work. Click here to read more »

The Joybox

Here’s a little thing I made for Emma from experience.
Click here to read more »

Kequencer 2.0

The original Kequencer got way more attention than I expected, so I’ve built another one and done a more comprehensive build report to make it easier for people to replicate. Click here to read more »

LDR DAC Melody Generator

At the workshop last week a ten year old came up with a DAC design I’d never thought of before, which we turned into a really cool and simple melody generator. In the schematic you can see the first three clocks blink the LED’s on and off at different rates (try 4.7u caps and 1M pots). As the amount of light falling on the LDR changes in uniform steps, you can hear the pitch go up and down in a musical way. You could actually tune this to a musical scale if you tweaked the spacing of the LEDs, and put the whole thing in a black box away from ambient light.

CALH 2011 DIY Synth Making Workshop

I ran my first workshop series over three days at Camp A Low Hum this year, teaching about 100 people how to make bleepy noises and blinky lights. I got to meet a lot of great people and infect a couple of them with the DIY electronics bug. I’m now in the process of refining my teaching materials and parts kits (supplied by the very rad Mind Kits) and then I will be running more workshops at my place in Wellington, and selling the kits online. For now you can download the tutorial booklets in their current state: booklet #1, #2. If you want to be notified when the next workshops will be running or when the kits will be for sale send me an email or leave a comment.


I had an idea the other day and I couldn’t decide if it was good or not so I just built it to find out.

Click here to read more »

Synthbot Schematics

The circuits in the synthbots are pretty straight forward. Send me an email if you’d like to learn how to build your own – it’s cheap and choice!
Click here to read more »

Lunetta: lo-fi noise synth

If you were at the exhibition opening you would’ve heard this noise machine I built. Click here to read more »

Synthbot Exhibition now on!

My exhibition is now on at Deluxe Cafe for the next two weeks. Go in and have a play with some singing robots, or check it out online here.

Homemade Oscilloscope

You wouldn’t believe how easy it is to turn an old TV into an oscilloscope. Snip a couple of wires and switch them around, then add an input jack and you’re away. In the video I’m displaying the audio from the TV tuner, but you can plug in any source.

Click here to read more »

Weltmeister Combo Bass

My pal Vic has given me her Weltmeister Combo Bass keytar to reinvigorate. There’s not a great deal of info online so I’ll collate what I know here in the hopes that it will be helpful to someone else in the future.

Weltmeister Combo Bass
Click here to read more »

4-stage Gated Oscillator

The first project I’m teaching in my DIY synth course is a 4-stage gated oscillator. It takes a couple of hours to put together, costs about $30 in parts, and is a good starting point for absolute beginners. So what’s going on in there?

Click here to read more »

Electronic Audio Hardware

I’ve been reading Handmade Electronic Music by Nicolas Collins and it’s possibly the most informative electronics book I’ve ever read. It presumes absolutely no prior electronic knowledge of the reader, starting with the most basic introduction to circuit bending (think wet fingers inside open radios). He focuses on maximal fun for minimal effort and it’s late in the piece before he starts explain circuits of any appreciable complexity. For the most part these circuits are incredibly clever and pack a lot of functionality into a few components. I’ll be working through some of his suggestions and posting my progress here. A simple project that caught my eye was the DIY spring reverb (guitar amp -> cheap audio transformer -> piezo -> slinky -> contact mic -> amp). He also has a lot of helpful information on using CMOS logic as the basis of synthesisers and signal processors (something I’ve been reading a lot about lately).
Click here to read more »