Reading Serial Data from an MB-TMB880CF-1 Temperature Module with an Arduino Mega R3

The TMB module is a simple and reliable clock & temperature reading module from the late 1980's and early 1990's. It has an on board LCD display, a built in temperature sensor and is powered by a single AA battery. It can be used as a clock and can display the temperature in °C or °F.
By default the TMB module reads the temperature and refreshes the display every 10 seconds. At the same time, it outputs the temperature as a serial stream of BCD data on pin 9, and that is accompanied by a clock pulse stream on pin 10. The serial data is stable and can be read on the falling edge of each clock pulse.
Oh, and the clock/data streams, whilst clearly digital are only a maximum 1.5v p-p, depending upon the condition of the AA battery. I found that they were 1.35v p-p out of my TMB module... not a lot to work with!
Using my Mega and it's built-in comparator I was able to detect, read and measure the clock pulses. Then on the falling edge of each clock pulse I use an analog input to read the data.
All code, and more, is on GitHub: github.com/iln...
The gear I used to help me make this video:
Owon VDS1022i USB Oscilloscope:
www.amazon.co....
Better (unofficial) Software for the VDS1022i:
github.com/flo...
Note that I am not affiliated or linked to any of these products, other than having used them and liked them.
Enjoy!
#Arduino #comparator #MBTMB880CF1

[@adrianbrindley1925]

Nice project again & explanation of the in-built comparator approach for the voltage level + thanks for the time sharing this and the code upload to github.

[@keithlohmeyer]

Nice job getting that sorted out.