Day 4: USB control requests are working as expected. I like them because they maintain data integrity i.e. each request has its own name (number, and 2 additional words) and it is apparent what it's doing. In my case there is only one request "GET_TEMP_REQUEST" (check GitHub) which sends back 32 bits of thermocouple data to the host. The highest measured temperature of light bulb in my desktop lamp is : temp = 274.75°C. It's 1AM, and I must wake up at 6AM o'clock. Oh well...

Day 5: Added the relay. Lesson learned : beefy solid state relays won't work with little load. My works when load has at least 24V and 50mA (or more ?). So I quit supplying 5V and other funny voltages, and went with 230V AC. Little scary, but at the end it would operate with high voltage, so what the heck. So tonight I basically made 100W blinky :D Also, tested the thermocouple with toaster, and it peeked at about 200°C.