Upcycling

Thu Dec 19 18:39:06 2019
Sometimes something is donated but on receipt, it appears not to work. In this example, it was a bedside radio. The manual may not be present and the item may be too old to find on the internet. So the dismantling process is started. The item may be composed of many sub-modules and some of them may be identifiable electronic sub-units such as keypads, rotary controls for volume, motors (DC or stepper) and so on.
The markings on the case may be worn and thus not visible clearly which could be a reason for starting the dismantling process. Simply if it does not turn on easily. However, when the case is opened the silkscreens on the PCBs may be enough to work out the function of the buttons on the keypad and the interconnections between modules.
At that point, we have to choose whether to re-assemble or continue the dismantling. I usually continue the dismantling and learn from that process - hence this small write-up.
Some sub-modules may be connected to other sub-modules with cable assemblies which in turn may use recognisable plugs. The plugs may be unusual but the same as another project waiting for progress. The name of the plug which you may use in a catalogue of parts may be misleading or at least ambiguous. In the case of the bedside radio, the internal speakers and the battery backup used the same type of connector. The silkscreen labelling gives clear placement instructions. In this case, the plugs are the same as the battery connector on the Arduino Lilypad (type xxx) and the, recently made popular, BBC Micro:bit. Would you also believe that the connections for these plugs respect the same polarity! This means that a 3V power-supply that works on a Lilypad also works on a BBC Micro:bit.

From time to time DVD/CD devices are encountered. These have up to three small motors with their associated gearing systems to facilitate drawer opening, head movement and disc spinning. H-bridge drivers can be used to demonstrate their operation and may form the foundation of some small toys and even some ideas for robots. the DVD head movement motor is also associated with a travel stop switch which can provide a datum for movement and position detection.