Author: Joseph

IoT Hackathon at the Amazon AWS Summit, Cape Town

Yesterday I attended the Amazon AWS Summit in Cape Town. The talks were good – even Werner Vogels, the CTO of, showed up! Getting to speak to experts in their fields and AWS engineers from the world over was eye-opening for sure.

A couple friends and I participated in the IoT Hackathon, which Intel kindly sponsored. Given an Arduino 101 (containing an Intel® Curie™) and a Grove starter kit, we had a couple of hours to have fun and see what we could hack together. As we were new to AWS’s IoT platform and the Python libraries we were given, it took us some time to get it up and running but we ended up with a working prototype.

We designed a prototype of a notification system for a cold room refrigeration system to monitor temperature and door opening/closing events, which are sent over to the AWS cloud and logged. We planned to add a stepper motor to simulate our door among other features, but we didn’t have enough time; We had to just use a push button to toggle the door opening and closing.

Here’s a brief video of our setup, and some pics:

The members of team AckerTech, from left to right: Joseph Rautenbach (me), Matthew Baas, Torsten Babl, Bradley Fourie.

All in all, it was great fun. Our team came second place, so next year we’ll be back for round two!

Running American C7/C9 Christmas lights (110V) directly on a 220V supply

Whew, long time without another post – it’s been a busy time, glad to get back to blogging.
This post is going to explain the basics of using American 110V Christmas lights on a 220V electrical supply, by splitting the light string in half and putting them in series instead of using a dedicated voltage converter.

Last Christmas I was in the U.S. and, as a fan of large bulb C7 Christmas lights, I picked up a nice old set for a grand total of $9.49.

They looked and worked great in the hotel room, I just needed to modify them to work on a 220V supply that we use in South Africa (and most of the rest of the world). I could have used a voltage converter but this string uses over 100W, a large transformer would be needed ($$$).
A cheap and easy solution is just to split the string in half, and have both sections connected in series; each section would receive 110V.

Temperature-controlled Peltier Mini Fridge

UPDATE: Project featured on! See here
I recently finished up on my Peltier Mini fridge project, and it works great!
It can cool down whatever you want that’ll fit in it — six 330ml cans for example — and can get down to –2.1°C!
Watch the video for a full description and how it works. I gotta say, it’s really cool, excuse the pun!

Bitmap images on character LCDs

Character LCDs are displays that consist of many character “blocks”, and each block can display a letter, number, etc. In the world today, there is one display controller/driver that dominates this market, the Hitachi HD44780 driver. I have talked about this in another post on reverse engineering a printer LCD. HD44780-based character LCDs usually come […]

Playing video and other fun things on a Nokia 3310 LCD with Arduino

The Nokia 3310 LCD is well known in the electronics community; I decided to have some fun and get it to do things the designers probably weren’t intending it to ever do! 😛

This LCD is a monochrome graphics LCD with a resolution of 84×48 and while relatively old (1998), it’s brilliant for its very low price.

This controller uses the PCD8544 controller IC has an easy to use SPI protocol and handles all the hard work of driving this display (multiplexing, generating bias voltages, ect.) Using the display is relatively easy with any microcontroller, I used a breakout board for ease of access on a breadboard/stripboard.

G3ECS Hackerspace

I have been attending the George Education Electronics Engineering & Computer Society, or G3ECS, and have been really enjoying it. Anyone living in the George/Garden Route area should really attend this. We have a huge variety of people attending from all ages, and we are planning to build a couple of robots. I enjoy it […]

App video-demo: iOS4Life Mobile

I have uploadad a video which demonstrates an application I wrote up for a client. It loads and displays a master RSS feed and allows the user to view the content. The articles are sharable to many online services including Facebook, Twitter and Tumblr. You can also copy or email a URL to the article. […]