Snow Day Tinkering

I had this old Sony boombox that used a lot as a kid to listen to Bruce Springsteen or Jars of Clay cassettes. It had a lot of buttons on it, several moving parts, and even a small LCD. What better way to make use of a snow day than to take apart old electronics?

I was thoroughly surprised by the amount of electronics inside the player. There's a main board, a power management board, an LCD board, a radio board, and several mechanisms for cassette and CD playing. 

The main board had several small trimmer potentiometers on it along with 2 much larger potentiometers. I desoldered one of each of those along with the small LCD to see if I could figure out how their wiring worked. This was fairly difficult to do and I was afraid the heat might ruin the LCD.

To test the LCD I used the 5 volt and ground ports on the Arduino and just made different connections on the screens 8 pins. There really weren't any consistent patterns that I could make out, but the screen was definitely working. I tried looking up a pin-out online, but there isn't much support for a 1 in by 1 in display from a 90's boombox.

There is, however, a lot more support for wiring up a simple trimmer potentiometer. The potentiometer as three pins, a positive, a ground, and the signal (the middle pin). This signal is analog in that it doesn't send 1s and 0s, it sends a variable voltage. Rather that research exactly what this signal looks like, I decided to use another great feature of the Arduino, the serial monitor.  It allows me to hook up a sensor into an analog pin and then print out all the numbers that come out. Doing this, the returns range from  0 to 1023. 

To put the sensor to actual use, I wired it up with an LED. LEDs can be programmed digitally (on or off) or through an PWM signal. A PWM signal essentially turns the LED on and off so fast that it looks like it has a partial brightness. This signal is given by a number from 0 to 255. In the code, I just multiplied the input from the potentiometer by .25 to get the proportional output to the LED. It is more elegant than using one or two different buttons. In the picture, the potentiometer is the little yellow circle. 

I tried to do the same thing with the larger potentiometers but when I hooked them up to the Arduino they shorted (even with resistors) and created a lovely smell. Thankfully the Arduino shuts itself off before it gets destroyed by my ignorance. 

To see the below wiring in more detail or to take a look at the code click on the Projects page and follow the subsequent links. 

Soon I will either put the DC motors to use by buying a motor controller or I'll purchase some servo motors which I can drive directly from the Arduino.