Author: Joseph

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.
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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

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UPDATE: Project featured on Hackaday.com! 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. It is a monochrome graphics LCD with a resolution of 84×48 and was originally used in the Nokia 3110 and 5110 handsets, and is relatively old (1998), but in my opinion it is brilliant for its price.

I purchased mine on Dealextreme for only $5.60 (link to the product page here), which is a very good price considering what is possible with this display. It came in a nice breakout board so it can be used directly on a breadboard.

If you remove the casing on the breakout board, you will find out that the display looks just like a piece of glass, and has a PCD8544 controller chip embedded inside it.

This controller has an easy to use SPI protocol and handles all the hard work of driving this display (multiplexing, generating bias voltages, ect.).
Driving the display is relatively easy with any microcontroller. However, it runs on and uses 3.3V logic, so you would need level shifters to shift the voltage down.

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. […]

App: Glenwood House News

I have been working on an application for my school, Glenwood House.
It allows you to read all the latest news, upcoming events, view the latest images from the school gallery, download all the latest documents and get contact info for the main staff members.

I built the application using the iOS SDK. The way this application operates is by