Introduction: Vibration Bug
This article shows a vibration bug. The vibration speaker is activated when the bug is placed in water.
I learned from those articles:
Components: general purpose bipolar junction (BJT) NPN/PNP transistors - 5, 1 kohm low power resistor - 1, 10 kohm low power resistor - 1, 100 ohm (or 10 ohms) high power resistor - 1, matrix board, vibration speaker - 3.
Tools: wire stripper.
Optional components: solder, Schottky/silicon diode (do not use low power diodes).
Optional tools: soldering iron, multimeter.
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.
The maximum vibration speaker current is almost similar 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.
Participated in the
Make it Move Contest 2020