[sclug] Winter project

Bob Dunlop bob.dunlop at xyzzy.org.uk
Wed May 15 08:10:47 UTC 2013


On Tue, May 14 at 08:56, Neil Haughton wrote:
> The idea is to connect the GPIO via some buffering circuitry to my actual
> controller, to override the two switches that advance the CH and DHW
> cycles, and also to replace the present room stat with a temperature sensor
> that the Pi can monitor. The extra thing that would make this a useful

Get yea to a hackspace.  Lot's of info and help for you there.

Last night Reading Hackspace[1] hosted a SMD soldering class.
The example board they built was a PiBot[2] a GPIO expander for
the Pi with buffers targeted at driving stepper motors but could
easily drive relays as well.  Also sports several ADC inputs that
could be used as temperature sensors.  Not bad to a tenner
including the soldering class.

With lots of temperature sensors you could add some more interesting
instrumentation.  For example. Comparing two sensors spaced a meter or
so apart on the boiler outlet could give you the water flow rate,
although quite a challenge detecting the rising edge with any accuracy.
Combine the flow rate with boiler inlet and outlet temperatures and
you'll know how much heat you are actually delivering to the house.

[1] http://rlab.org.uk/
[2] http://solderpad.com/folknology/pibot/

        Bob Dunlop

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