Arduino and PeaceFair AC/DC Energy Meters

I had seen the AC and DC energy meter units from Chinese manufacturer PeaceFair. They looked interesting to me and were very low cost, so I ordered some DC and AC energy meters with RS485 Modbus communication. I want to read the data from them for a remote battery monitoring project. This post contains my … more

Talking to a DDM18SD Energy Meter

I had obtained three samples of a DDM18SD DIN rail mounted energy meter unit. I got mine from a UK supplier on eBay, but they are available here at AliExpress and in many different places. The unit I obtained was a single phase unit for directly measuring up to 5A and 240V AC, but up … more

Engineering in Development ‘Energy’ Book

Over the past two years a number of people have been working on a series of books for Engineers Without Borders placement volunteers. These books are designed to cover the basics of the theoretical, practical and social aspects of doing engineering projects for devlopment. They are meant as a basic guide, a collection of case … more

Designing Laser-Cut Enclosures

In this post I’m documenting my process for designing enclosures for some of my projects. This is the design process I use to produce bespoke enclosures with cut-outs, using the laser cutter at Nottingham hackspace and 3mm plywood. In this example I’m designing the enclosure for a power monitor with a large 7-segment LED display. … more

Voltage measurement

A number of our projects require accurate monitoring of voltages. Here we explain the numerous techniques for measuring voltages, both DC and AC, highlight some of the multitude of integrated circuits available and list the pros and cons of various techniques. To measure power (and hence measure energy) within electrical systems, we need to know … more

DIY solar PV panel information

Here are collected notes and ideas on building your own solar photovoltaic (PV) panel. These come from a number of places including attending a course run by Dan Quiggin of Demand Energy Equality, web-searching, discussion with Norman Phipps of Handmade Solar and also running my own DIY PV workshop at Nottingham hackspace. I feel that … more

Battery worksheet

This is an information and operation and maintenance worksheet for lead-acid batteries. It covers battery basics, the various types of batteries, battery safety and how to measure state of charge. This document is open source. … more


Solar PV lanterns

A report written for Digital Campus which reviews a number of solar PV lanterns with a view to deployment in Ethiopia. This report was written to look at using solar PV lanterns to recharge smart mobile phones in remote locations. … more

Solar PV design worksheet

This is a simple design worksheet for stand-alone solar PV systems. It explains the design process and explains some of the practicalities of building a system. This document is open source. … 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

Design documents for International Development projects

Here are a number of documents which were produced as part of my work at SIBAT, a Filipino NGO working in remote rural development. This placement was funded through Engineers Without Borders UK. This work covered project management, resource assessment, practical electrical and mechanical design. It has been written specifically for the Philippines, but most … 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