The project involves the use a string of bells that were originally designed to hang on a Christmas tree and play pre-programmed Christmas songs. Stringing the bells on the Christmas tree proved difficult as it was hard to align the bells properly on the tree and prevent the bells from touching anything. In addition, I wanted to add a keyboard for fun.
The instrument is made of teak. The parts I added include: the momentary switches (SPST) used for the keyboard, a piece of scrap circuit board to mount the switches, a slide switch (SPDT) and miscellaneous wire. All of this found in my parts boxes which were mostly garnered from things I have disassembled over the years. The keyboard switches have an internal resistance of 1K Ohms and avoid the necessity of adding the resistance to isolate and current limit the keys from the rest of the electronics. The picture above shows the keys from an old calculator.
The electronics was modified to add a switch to select the key board only while still allowing the pre-programmed music to play as well as maintaining the test position. The test position was needed to help determine if all the bells were ringing properly. The connections to the circuit board is shown in the picture.
The this picture shows the electronics compartment. The slide switch to the left is used to select the keyboard, music or test mode. The On/Off switch is located on the circuit board.
A video clip of the bells instrument being demonstrated can be found at facebook address https://www.facebook.com/groups/184834338312031/?fref=ts
Wayne, the man playing the instrument is the leader of the bell ringers at a local church and this was his first effort at playing it so had no prior practice.