Quantity   Component name
1 × W1209 Your favorite low cost thermostat unit!
1 × USB-RS232 dongle with TTL interface CH340, FTDI, Prollific, or old cell phone cable. Should be compatible with 5V signals.
1 × ST-Link V2 adapter Cheap if you're ready to wait for one to arrive from China. The cable that usually comes with it can be cut iin the middle and used to make the ICP and the serial port connections :-)