Arduino Flex Remote control

Pin assignments

Hardware required

Note on Arduino items: the whole project is based on genuine (or fully compatible) products. Additional software and support libraries has been developed starting from official  code.


Complete list of components you need for the  RC Box

The board Arduino Due is a microcontroller board based on the Atmel SAM3X8E ARM Cortex-M3 CPU (datasheet). It is the first Arduino board based on a 32-bit ARM core microcontroller. It has 54 digital input/output pins (of which 12 can be used as PWM outputs), 12 analog inputs, 4 UARTs (hardware serial ports), a 84 MHz clock, an USB OTG capable connection, 2 DAC (digital to analog), 2 TWI, a power jack, an SPI header, a JTAG header, a reset button and an erase button.

  • Official Arduino Ethernet Shield -  It is the best board that allows your Arduino to access the network at 100Mb/s. It is also the board that has the best support libraries. I tested other equivalent ethernet shields, but with no success.

8 Channels 5V Relay Module


RS232-TTL converter


You need three of it. Two are reserved for Flex Cat Protocol and one for rotator control.

Green Led and 220 Ohm resistor


It is used for status informations.

4N35 Opto-coupler and 220 Ohm resistor


You need three of this opto-coupler. They are used for "Remote On/Off", "Remote CW key" and "Remote AC power switch" functions.

USB cable for remote cw key

The remote cw feature requires a particular USB cable. The control software senses the CTS line of a serial port installed on your personal computer. The CTS line is connected to a stright key or to the output line of your preferred CW Keyer. You can avoid the USB-RS232 adaptor plus DB9-3.5mm jack connector using a stringht FTDI USB cable like in the picture below. 

Follow the name lines to wire the 3.5 mm jack and don't use the color scheba because it is different from one model to another.. You nead also a small ceramic capacitor (104) and a 0,25W 6K8 resistor.

Try to do a small welding job so you can fit the mini circuit into che 3.5mm jack.

The perfect cw-usb cable with my small Pico-Keyer :)