Rotaoptics.

There are so many sophisticated products in the market place having all the exciting dynamic attributes of colour, sound, movement and bright lights and all so cheap. How can we compete? I am sure many of you have pondered this and of course the answer really is that we cannot! We can however have a best shot at emulating the best. Not forgetting all the educational value in designing and making products, through which, we are nurturing our young learners.

There are many toys on the market which have all the essence of excitement through movement, colour and sound as mentioned above. Just type "LED spinning toy" into a search engine and you will see what I mean.

Always on the lookout for something inspirational I purchased a simple spinning top. When you spin this toy 4 ultra bright LED’s burst into life to give a surprising changing array of patterns.

On closer inspection (taking it apart) I discovered an hermetically sealed programmable controller, 4 x 3mm LEDs, 3 button cells in holders, and a high quality PCB all housed in a sophisticated injection moulded body.

The initial intention was to provide an activity which did not need a PCB (printed circuit board) and soldering irons for the production. However to gain a similar effect to the spinning top, LEDs and a battery supply with other ancillary components would be needed.

 To gain a similar effect to the programmed LEDs of the spinning top I decided to utilise 4 ultra bright flashing types.

 The power source needed to provide around 3 volts with enough current to drive and sustain the 4 LEDs

 To provide a type of centrifugal switch it seemed obvious to use a tilt switch. Perhaps non-mercury being safer.

 For convenience, speed of manufacture and not least providing a CAD and CAM opportunity, the body components were to be manufactured on a laser cutter or milling machine.

The components are all from Rapid Electronics listed below:

55-1892 flashing red led x1
55-1894 flashing yellow led x1
55-1896 flashing green led x1
55-1898 flashing blue led x1
18-0121 1aa flying lead battery holder x1
18-0461 horizontal pcb lithium battery x2
18-1442 Heavy duty zinc chloride AA x1
78-0100 push to make switch red x1
78-0754 non mercury tilt switch x1
37-0142 3 volt miniature motor x1

Also needed are 2x9mm long self tapping screws and washers to hold LEDs and 4x 6mm screws with washers　to hold other components.

Use a double sided sticky pad to hold the　battery holder in position.

The two main methods of connecting electronic components used here is through a clamping method using self-tapping screws and plastic sleeving to give a friction fit. – Soldering is minimised and productivity improved!

Use the two longer self-tapping screws to clamp the LEDs

The LEDs can be awkward to fix together so best to use a piece of sleeving to hold all anodes and cathodes together…. Can be a fiddle so persevere!

Button cell batteries need to have their PCB mounts extended and clamped as shown in picture

Make sure the tilt switch faces inwards so that it works as a centrifugal switch.

Use a double sided sticky pad to hold the　battery holder in position.

The handle which holds the push to make switch, ‘AA’ battery and motor should be self explanatory from the images. Note the wires are connected to terminals by utilising sleeving.

The original intention was to provide an activity which had no soldering or PCB. However some comments from teachers indicated that they would like to see a more robust solution where:

 Button cells held in pcb mounted battery holders

 LEDs soldered in position

 PIC based solution (to follow)

Please contact Allen at allen.bower@staffordshire.gov.uk for further information on this project and look out for PCB layout on the DTEP website