Theory and instruction
In the previous article(Light Sabre Energy Stick Series: Sound and Light Module, an Introduction to Light communication) we used a music IC and an LED to send audio signals with visible light, and then used a solar panel and a piezo buzzer to receive and transfer to audio signals. This time around, we are using the dazzling feature of an energy stick to turn the entire stick into a visible light message launcher.
Bill of materials:
- A solderless breadboard
- A battery snap
- A 9V battery
- LED string lights
- A music IC(TO92- XC64GU)
- A Darlington transistor MPSA13
- A power transistor(SS8050)
Assembly steps and instruction
Insert the LED string lights and music IC into the breadboard, then connect the 9V battery. Once the circuit is complete through human body the LEDs will blink to the frequency and rhythm of the music IC.
To use this device well, we need to take note of the following things:
- If you want to use the TO-92 music IC for the LED string lights, you might not get enough electric current and hence cannot light up the entire string of LEDs.
- Which is why you need an additional power transistor, so you can boost the power transistor with the music IC first, and then boost the LED string lights with the stronger current of the power transistor.
- This module demonstrates several ideas: the 1/24 second persistence of vision, the 20-20K Hz of the human hearing range, and energy conversion.