Minimag Co.

Ignition Systems

Rotary Clock Kit


This kit will enable you to build a timepiece featuring a "persistence of vision" LED readout.

This is an advanced project involving machining work, electronic assembly of conventional and surface-mount components and a little hand coil winding. 

The finished clock is uncased, it is left to the constructor to make a suitable housing and stand. The assembly is sized to fit inside a Norton Wankel engine rotor which was the basis of our prototype. You may have seen it on our stand at recent model engineering exhibitions.

Principle of operation
A line of 8 LEDs mounted on a counterbalanced rotor arm is caused to rotate at high speed. The LEDS are switched on and off at predetermined times, referenced to a fixed point. Due to the high speed of rotation the eye perceives the rotor as a fixed display. Each displayed character is formed in a 5 x 7 dot matrix. It can display numerals 0 to 9,  letters A to Z in upper case together with a few special characters. the innermost eighth LED is used to form a cursor to aid programming. Timing and rotor dimensions allow for twenty characters to be visualised. In operation the display cycles between time, date and a programmable user message. A three-phase motor drives the LED rotor, providing stable and low vibration running. Power and display data is transmitted to the LED rotor through a novel air-gap transformer, avoiding the need for slip rings and brushes. Clock timing is generated by an accurate crystal-controlled timekeeper and maintained by a supercapacitor in the event of a power outage. 

What's in the kit:

Black Acetal material to make the stator and rotor bobbins
2mm aluminium sheet to make the front and rear plates
Brass for the counterweight
Complete set of fasteners
Three high-quality double-sided and plated-through printed circuit boards
Electronic component packs, one for each board
Enamelled copper wire for winding the air-gap transformer
Pre-assembled interconnect wiring
Pre-programmed and tested microcontrollers, one for timing, one for the rotor arm.
Three-phase motor
Reference point magnet
Plug-top power supply
Printed build manual
Drawing pack

You will need:

Small lathe
Vertical slide or small vertical mill
M3 tap
Small drills
Soldering iron with a fine tip
Resin-cored electronic solder
Electronic tweezers, pliers and side cutters

As with all our products, telephone and email help is always freely available.

For pricing, to place an order or obtain further information, please contact us

Solenoid Engine Kit

Solenoid Engine
By popular request, we've produced an unusual "engine" operating on electromagnetic principles. Although of little practical use, the engine demonstrates an alternative means of producing rotary motion by electricity.

The "piston and cylinder" is a high efficiency solenoid actuator coupled to an eccentric shaft and flywheel. A single 1.5V AA cell provides enough power to run the engine for many hours. 

Timing for the power stroke is obtained using a magnet embedded in the flywheel which operates a sensitive reed switch. There is no ON/OFF control. A gentle flick starts the engine going, when stalled, the design ensures that the solenoid remains de-energised.
The engine is available fully built and tested and also as a kit of parts including bearings, fasteners,bar stock and high density plastic material for the base. A full set of A4 drawings accompany the kit. Easily built in a day's workshop session.
A comprehensive build manual in PDF will be emailed once your order has been placed.  
 Photo shows the MSE-1 (assembled and tested version)
See it running at:
Overall dimensions: 63 wide  X 110 long  X 60 high
Bore and stroke: 8mm by 6mm
Speed: Approximately 1000RPM on a new cell.
Power: Single AA cell in a compartment in the base.
Big end: Ball bearing
Small end: Plain
Mains: Ball bearings
MSE-1-KIT       Solenoid Engine, kit for home machining                       £54.30
MSE-1             Solenoid Engine, fully machined, assembled and tested  £108.00
Please contact us if you would like to place an order.