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Training the hand and mind since 1982.

Wednesday, February 6, 2013

Digital Temperature Probe (Freshman Project)

Here a new project that I designed for the freshmen. It's based on the ATMEGA328 / Arduino. This is a replacement project, the cost of older components were getting prohibited thus we discontinued the temperature probe project a few years ago. In the old project we used PM-128E voltmeter and the LM34, the old project cost was around $30 for the meter and the LM34.

Since the new redesign with the ATMEGA328 at $1.60 and the Blue LCD direct from China $2.20 and the new temperature sensor MCP9700 at $0.19. Total cost around $3.99 each for a lot of 100.

Some additional features to the new project include:

* Splash Screen with students name and email
* Display of C/F/K (internal math functions)
* Support for up to 5 Temperature Zones or other sensors
* Firmware controlled Back-light
* Sleep mode
* PCB Backpacked behind LCD for a slim design
* Optional alarm mode or temperature controller (TBD)

CODE: Coming Soon

HEX: Coming Soon




Prototype With Arduino
Splash Screen (5 Seconds)

Temp, (Cold in the shop today) 


Ditched the Arduino once firmware was okay


Got a bit warmer


PCB, I haven't milled it out yet. Concept drawing only, once verified I'll post the new revision and snap some pics of the prototype. The PCB is the same size as the LCD and will fit behind it. As a design rule it has to be single sided and thru hole, thus you see three jumpers in pink. A nit tight to fit in a 6th analog port so I left it out for now. Pins 24-28 have a three pin header for sensors (+V/GND/Ax)