This indicator circuit used and game machines (arcades) to indicate that the machine is being shaken was found in NASA documentation. The circuit uses as a sensor a container with water and three sensors.
With this circuit it is possible to receive and send audio signals simultaneously over the same...
This circuit was found in a Popular Electronics of the 90's. The circuit makes use of common...
We found this circuit in an American documentation from 1964, but it can be easily assembled...