Beep-O-Matic: Waveform Generator

For this project, I generate arbitrary waveforms by creating a PWM signal from a generator (in this case, the ATMega328), run it through a low pass filter, and have the waveform as the result.

For more see the main page on the project, see the

Beep-O-Matic Waveform Generator

Boulder iOS Meetup: August 2013

On August 23, 2013, I presented my Bluetooth 4.0 Low Evergy interface to the Boulder iOS Developer meetup. I presented my bluetooth low energy device All the way from circuits to the iOS application. Going from Hardare to software hadn't been done before in the meetup, so that was pretty cool.

Morse Code!


To enclose my latest Morse Code CW Keyer project in a quick and simple enclosure that is better than the breadboard and stack of three shields as described in the original article

Morse Code Arduino

Original CW Keyer

Uncovered CW Keyer prototype without lid.

Uncovered CW Keyer prototype without lid.

and finally into this:

Final covered prototype.

Again, see the original article at

Morse Code Arduino

for full details on assembly.

Sine Wave in Your Kitchen


I needed a way to enclose my electronics projects that was easy and cheap to build. In Making Things Talk by Tom Igoe, he mentioned using plastic kitchen containers as project enclosures. So I decided to give it a try.

The circuit came from Timer, Op-Amp & OptoElectronic Circuits & Projects by Forrest M Mims III. Page 79. I don't reproduce the schematic here for copyright reasons...however, I recommend this book highly! It is a great lesson on how we did things before pervasive and cheap Arduinos ;)

Before & After

transofrmed the breadboard on the left into the kitchen container enclosure on the right.

741 op-amp sine wave oscillator on breadboard.

Sine wave oscillator in a kitchen container enclosure.

Parts List for the Enclosure and PCB

Parts List for the Circuit

  • 741 op-amp

  • 2 9V battery clips

  • 100 kilohm potentiometer

  • 4 0.01 microfarad capacitors

  • 1 kilohm resistor

  • 1 10 kilohm resistor

  • 2 27 kilohm resistors


I used a little cordless screwdriver/drill from Ikea to drill in the plastic. The plastic was slippery, so I tapped the holes with a little nail before drilling. Also I drilled both sides of the lid.


Quick and easy: it was successful and I have already used it for another project. More to follow on that in a later post.