PRESUMPTION
- MCU: PIC-processor
- Voltage supply: 3.7-12VDC
- Current consumption: 20mA
- Frequency range: standard 2-3000Hz
- Weight: 150 g
- Body: Plastic or aluminium
- Temperature range: -40°C to +85°C
- Connection: wired
The Geophone and the RMSensor was tightened to a metal frame with a mutual distance of 60cm.
The Signal above was generated by a gentle tap on the metal frame (in the middle between sensors) using a pencil.
The Geophone did giva a very noisy output voltage signal of 0,012Volt (12mV).
The RMSensor generated a low noise signal ouptput of 1,34V (1340mV)
The pin drop
Have you ever heard the expression “You could have heard a pin drop” ? The point is that sound of a pin dropping is so weak that the room must be very silent for humans to hear it.
We figured this would be a great challenge for our RMsensor. A pin (needle) weighing approximately 0.2 grams was dropped 2 meters away from the RMsensor, only 5 cm above floor level. The RMsensor standing with probe against floor surface (no fixed termination towards floor which would have increased sensitivity further). The oscilloscope measurement shows how sensitive the RMsensor is.
Amplitude 40mV/div. Timebase 1ms/div.
The datalogger picked up the 40mV signal, amplified analyzed the frequency components. The generated frequencies of the dropping pin matched the alarm parameter settings in the datalogger. An acoustic alarm using a piezo buzzer was generated instantly for every bounce the pin made towards the wooden floor.
Test result: Pass with flying colors !