M15A Wireless Remote Controller software

Master unit

The original FS15A control panel has six illuminated pushbuttons, a tape speed toggle switch with two indicator lights, and additionally a mono/stereo toggle switch and a “Ready” indicator light. The pushbuttons are break-before-make changeover switches. These are hardly available anymore, and I don’t immediately see their added value either.

My wireless version uses Japanese NKK pushbuttons, series KP01-15, with LED illumination, available from Digi-Key (USA). These buttons feature a tri-color LED—not necessary, but it was the only model in stock at Digi-Key. Any other button can be used as well, but the PCB design is based on the NKK buttons.

The design uses an Arduino Nano CPU module to read the buttons and switches and to control the LEDs. The status of the buttons and LEDs is thus translated into serial commands, which are sent to the slave unit via the Bluetooth module. Although not strictly necessary, I chose to connect all LED colors. This brings the total number of LEDs to 24. The Arduino Nano doesn't have that many output lines, so three TPIC6595 shift register ICs are used to solve this. The open-drain outputs of these ICs also make it possible to drive incandescent bulbs, each output can switch up to 200mA.

The pushbuttons and switches are connected directly to the Arduino Nano. The Bluetooth module is connected via a software serial port, which keeps the hardware port available for programming and debugging. The software serial port runs at 38400 baud, which is also the maximum baud rate that a software serial port can reliably handle on a Nano. LED D4 is the status LED for the unit: green means power is on, blue means a Bluetooth connection has been established. The entire module must be powered by a 5 Volt DC power adapter (max 1A).

The code is written and uploaded with Arduino IDE version 2.3.5

For donwload of the code use the download button