Presented here is a selection of electronics projects that I have designed and built over the years. As a minimum there will be a description of the circuit and schematic diagram. Most designs also include PCB artwork, normally in Eagle CAD format. All the data information presented here is provided under a Creative Commons license, so please learn from and use it.
Creative Commons License
Micro controller projects by Ian Stedman is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.

Electronics Related

USB to 3.3V power adaptor
A simple circuit to provide 3.3V from a USB port. It was created to power a demonstration board that required this supply which was normally hooked upto a PC, hence the use of USB to draw +5V.

A 7.2V NiCad/NiMh Rapid charger
Charges a 6 (or 8 cell) battery in 22 or 33 minutes based on the Maxim MAX 713.

A 5 hour rate slow charger.
A simple, easy to construct charger, easily made from scavenged parts.

A simple Transistor tester

Re-using an ATX PSU
Ideal for using it as a cheap, high current power supply.

Audio mixer
An stereo audio mixer and amplifier circuit, suitable for use with a computer. Provides 250mW of power per channel

An updated audio mixer,
with better fading for the Amiga computer.

A collection of TTL interface circuits

A cheap, low cost current monitor, new that measures currents from 0-20A and can be easily interface to an ADC in a microcontroller.

Microcontroller based Projects

A simple, 8 pin PIC12FXX development board

Another, simple, 8 pin PIC10FXX development board

This information has been copied from the Microcontroller projects section

Game Timer   
A microcontroller based, easy to use 30 & 60 second timer for those board games that require such a time delay.

A PIC programmer for the Amiga and a program/circuit to allow a PC-Keyboard to be used with an Amiga

Edge detector
This was built to detect pulses from a Radio control receiver and act upon them, as a servo or Electronic Speed Controller (ESC) would. It uses a PIC12F675 to detect and measure the pulse widths.

Servo Tester
There are two variants of a Radio Control servo tester here, one uses the PIC12F675 development board with a variable resistor to set the pulse width, for a real analogue feel, the other is a rewrite of the software for the design published in the Elektor Electronics July/August 2006 edition, using a PIC16F84A/

FTDI USB to PIC microcontroller
This design uses the PIC16F88 microcontroller with the FTDI FT232 USB to UART interface device. Example code to interface between the PIC micro-controller and the FTDI USB device is available, for the PC, Eeither Hyperterminal or PuTTY software is used to communicate with the PIC.

Tone detector
This was test software for my solar lighting system, to detect a >400Hz tone and if detected, turn on an indicator LED. It makes use of the capture block of the PIC16F627A and the on-board comparators, which shape the distorted audio signal.

Solar lighting controller
This describes the control electronics and associated software to control a number of LED light clusters, powered by 12V and re-charged via solar panels. The charging is not controlled by this system, off the shelf charge controllers are used for this, this module works with sensors and switches to activate the lights when required.

Amiga Hardware hacks

Click here to enter the Amiga Hacks zone.  where you will find information on Amiga hacks I have done, A1200 hardware information and more.

Teletext decoder review. A review of the Teletext decoder I built many years ago.

Computer I/O cards

24 bit digital I/O card (WIP) for the parallel port

By Ian Stedman, updated 1st February 2010

Updated 14 April 2021