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Analogue Clock - I2C DAC Shield

Status: Proposal
January 6, 2015

 I would like to build an analogue clock using old fashioned Voltage meters to display the hour, minute and seconds.

Using a networked Arduino or PICduino (or other controller), this shield provides a six channel DAC with additional Op-Amps for trimming each channel. With six channels one could use

a) an analogue meter for each digit, or

b) 1 meter each to display Hour, Minutes and seconds

with the other two meters to display a pseudo energy level, temperature, mood or whatever.

I'm planning to use a networked controller, either Arduino + Ethernet shield or a PICDuino, with Networked Time Protocol, (NTP) to pull the correct time from the web.

If I can get this working with Power over Ethernet it could mean a single cable to power this old fashioned clock. When switched on, after booting it will just display the current time automatically.

Of course, one could use this six channel DAC for something else.

The Circuit:

Refer to the diagram.
Using only Through Hole components and based on the I2C DAC from Linear technologies LTC1665 (10-Bit) with the trusted LM358 for trimming.

Driving the op-amps with higher voltages, e.g 22V the outputs can go far beyond 5V.


To Do:

Demo board and Software...

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