Vibration Bug
Intro: Vibration Bug
This article shows a vibration bug. The vibration speaker is activated when the bug is placed in water. The device also works as a touch switch.
I learned from those articles:
STEP 1: Design the Circuit
The vibration speaker is modeled as 500 ohms. Various speakers have different resistor values.
Calculate the maximum vibration speaker current:
Ivbs = (Vs - Vsat) / (Rspeaker + Ro)
= (9 V - 0.2 V) / (500 ohms + 100 ohms) = 8.8 V / 600 ohms
= 14.66666666 mA
Keep in mind that you might need to use a 10-ohm Ro resistor value instead of 100 ohms to increase the current value.
STEP 2: Simulations
I used the old PSpice simulation software, student edition version 9.1.
The maximum vibration speaker current is almost similar to the predicted value.
STEP 3: Make the Circuit
I created the circuit on a piece of cardboard. Using a matrix board is a better method due to risk of water damaging your cardboard circuit.
STEP 4: Attach to Board
I used blu tack to attach the 9V battery, circuit, and leads to the wooden board.
STEP 5: Testing
Testing shows my sculpture is working.