[OpenTRV-dev] Schematic is good

[Damon Hart-Davis]

You can have the whole lot, + schematic!

https://sourceforge.net/p/opentrv/code-0/HEAD/tree/trunk/Arduino/V0p2_Main

https://sourceforge.net/p/opentrv/code-0/HEAD/tree/trunk/Arduino/V0p2_Main_PCB2

Note that the important parts of the code for this purpose are spilt between:

https://sourceforge.net/p/opentrv/code-0/HEAD/tree/trunk/Arduino/V0p2_Main/Power_Management.cpp

and:

https://sourceforge.net/p/opentrv/code-0/HEAD/tree/trunk/Arduino/V0p2_Main/RTC_Support.cpp

and their respective header files.

Tell me if you want me to highlight the right bits.

The whole thing is packaged as an Arduino 'sketch'.

Rgds

Damon


On 17 May 2013, at 12:39, Stuart Poulton wrote:

> Damon,
> 
> Looks good, out of interest (following on from you tweet)
> 
> "Good slides! BTW, I have ATmega328P down to 1.3uA@~2.4V (2xNiMH AA cells) running software RTC, EMAIL ADDRESS HIDDEN from int 8MHz RC."
> 
> Can we take a peak at the code ?
> 
> Stuart
> 
> 
> 
> On 13 May 2013, at 15:23, Damon Hart-Davis wrote:
> 
>> Hi,
>> 
>> (CCed to the list for general geeky interest, as we are starting to firm up the schematic and think about the PCB for V0.2-Arduino see https://sourceforge.net/p/opentrv/code-0/HEAD/tree/trunk/Arduino/ , Bo is asking why I have not put a supercap on the ATmega board.  I maintain the RTC in software on the ATmega328P using about 1.3uA, and there is no trivial way to keep that running while repowering the rest of the circuit, eg when replacing batteries.)
>> 
>> I've taken a slightly different approach.  The time is saved every 15 minutes.  (Using 1 byte of EEPROM for intraday time in a way that should be OK for 12 years continuous activity.)
>> 
>> Thus, on swapping batteries you lose on average 7.5 minutes, 15 at most, if you are quick putting new ones in.
>> 
>> Considering the potential need to make two adjustments per year of 1h for DST, a probable timing error of 1s/day (ie 10mins/year), and a battery life of a year or two, that doesn't seem too bad to me.
>> 
>> We *could* mess around with supercaps and diodes and so on, but this seems good enough for government work...
>> 
>> Rgds
>> 
>> Damon
>> 
>> 
>> On 13 May 2013, at 14:52, Bo Herrmannsen wrote:
>> 
>>> at this point i got a thought... how do we keep time in case power fails?
>> 
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> 
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