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The original completed Ambug Circuit


The Ambug is a two wheel robot designed by Rupert Goodwin and was available in kit form from the company Magenta Electronics Ltd.

Whole project was published by Amstrad Computer User in May of 1987 (pages 44-53).


The hardware consisted of a base board on which the circuitry and geared motors were mounted. The robot had only two wheels, with plastic / metal runners at the front and rear of the board for balance. The motors were simple low voltage DC motors mounted in a plastic gearbox which could be configured to deliver the required ratio. The kit was available for the CPC, PCW and for the PC.

The Circuit

The circuit consists of two quad TTL OR gates (7417) which drive a simple discrete H-Bridge configuration allowing bi-directional control of each wheel separately by setting the associated bits high or low. Two sensors mounted at the front of the base board allowed the robot to report making contact with an object. The motor hardware is controlled directly from the CPCs Printer Port, which limited the movements of the robot to the length of the connection cable. The inputs are read through the CPCs Joystick Port. A 2 Meter ribbon cable was supplied for this purpose. The circuitry is non-intelligent, so all control is done through software on the CPC.

Construction Documents

Below are the original construction documents supplied with the kit. The hand-drawings and notes are part of the original instructions and were not added by the owner.