sensors
Cardiophone
The human heartbeat can be made audible by using this cardiophone circuit. It is basically an audio circuit coupled to a probe made specially for the purpose of picking up electric signal from the human heart.
To get the best signal, place the probe’s electrodes to a point close to the heart. The preferred point is [...]
Presence detector, proximity sensor circuit
This circuit react in presence of any conductor object including humans. This circuit does not detect object movement but can act as an proximity sensor!
Sensitivity is adjustable with P1 which will be located at a great distance from the rest of the presence detector circuit.
The presence detector is built with an Clapp oscillator at 1MHz.
Do [...]
