[Rajendra] found an easy way to make a USB temperature logger.
He already had a USB to UART adapter that takes care of the
heavy lifting. On one end it’s got the USB plug, on the other a
set of pins provide a ground connection, 3.3V and 5V feed, as
well as RX/TX lines. To get the hardware up and running all he
needed was something to read a temperature sensor and push that
data over the serial connection. An 8-pin microcontroller in the
form of a PIC 12F1822 does the trick. It runs off of the 5V pin
on the USB-UART, and uses the ADC to get temperature data from
an MCP9701A sensor. The sample rate is hard-coded into to the
PIC’s firmware, but adding a button, or coding some serial
monitoring could easily make that configurable. [Rajendra] used
Processing to write an app which displays the incoming
temperature info and uses the computer to time-stamp and log the
inputs. We could see this as a quick solution to tracking wort
temperature during fermentation to make sure your beer comes out
just right.