Bus Pirate

The Bus Pirate is an open source test device designed by Dangerous Prototypes. It can test a number of common protocols including SPI, I2C, MIDI etc and also works as a 40MHz frequency analyser and 1MHz logic analyser. I was recently lent a Sparkfun Bus Pirate version to have a play with. It is configurable … more

Wifi and Arduino test

A while ago I bought one of these kits which included an Arduino clone and a Roving Networks wifi mdule. It is meant to be the cheapest way to get the Arduino onto a wifi network and hence send data out to the world. This blog post is my notes on getting it all working … more

Measuring temperature

Measuring temperature is incredibly useful. It is probably one of the most important environmental variables and there are a wide range of devices to do this task. I have recently had a number of projects which require accurate temperature measurement and storage, including a data acquisition system to measure hot water usage and a monitoring … more

AVR Dragon to program Arduino Bootloader

Following on from my post about using the AVR dragon to program blank AVR ICs, here is the process of buring the Arduino bootloader code onto an ATMEGA 328P. Firstly install AVR studio 5.0, as explained in the previous post. You will also need a version of the Arduino IDE installed. This post is for … more

Using the AVR Dragon programmer

I have got my hands on a AVR Dragon programmer and on-chip debugger. This is a low cost unit for the ATMEL 8 and 32bit microcontrollers. I was wanting to program some ATTINY85 microcontrollers (to make TV-B-Gones for a Nottinghack workshop amongst other things). I got mine from Farnell electronics and it was around £40 … more

Which micro-controller to use?

“There are so many micro-controllers. Which one do I choose?” This is common question within the world of electronics design. Here I list the main contenders and their development tools. I’m trying to give advantages and dis-advantages, but these could be very different for different projects. I’m also listing the main development boards and which … more

DC current measurement

A number of the projects we are involved with require accurate monitoring of DC currents. Here we explain the numerous techniques for measuring DC current flowing in a line, highlight some of the multitude of integrated circuits available and list the pros and cons of various techniques. This is an on-going work – please post … more

Measuring AC current

For a recent project I was asked to measure the current from a solar photovoltaic (PV) system. This is a typical request as knowing the current is useful for control systems and for measuring power and energy. This blog post highlights some issues and ideas for measuring current. … more

Sure 8x32 LED display test

Using dot matrix LED display with arduino

I am working on a project to display some text and graphics as the interface to a race timer (for the solar cars in schools project here). To do this I had obtained some 8 x 32 LED dot matrix displays from Sure electronics. I had decided to keep the development time to a minimum, … more

Making Printed Circuit Boards

Recently I produced a workshop on making your own printed circuit board for a Hack Space in Nottingham I am involved with. A Hack Space is an open workshop where people can use collective tools and share ideas, knowledge and work on group projects. As I had written the presentation, I thought it would make … more

Electrical system design guide

This was a practical guide produced while working for SIBAT, an NGO working in the Philippines, on a 1kW wind turbine off-grid system for remote community electrification. This work was part of a one-year placement in the Philippines funded by Engineers Without Borders UK. … more

Expanded scale voltmeter

While working on a wind/PV system in a remote area of the Philippines the need   for a voltmeter which showed the system (battery) voltage in detail arose. Only analogue V and A meters were available in the local town. This simple design explains in detail how to convert a low range ammeter into a voltmeter … more