<div dir="ltr">not if you ask me....<div><br></div><div>of course the pi can talk direct to the RFM etc.... </div><div><br></div><div>but yes its a cheap failsafe in case the SD goes bad etc</div></div><div class="gmail_extra">
<br><br><div class="gmail_quote">2014-07-29 12:21 GMT+02:00 Kevin Wood <span dir="ltr"><<a href="mailto:kevin@the-wood-family.com" target="_blank">kevin@the-wood-family.com</a>></span>:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Hi Stuart,<br>
<br>
You make a valid point. There's probably not much, if anything, there that<br>
the Pi couldn't do itself.<br>
<br>
Having said that, one of the other requirements is that it needs to be<br>
fairly robust against power cuts, so the AVR started out as "supervising"<br>
the Pi - providing battery backup power, commanding the Pi to shut down<br>
cleanly when the power fails and so on, and it then seemed sensible to<br>
make that also responsible for the other time-critical interfaces such as<br>
driving the RFM and the dallas sensors. In fact, I have it in mind that,<br>
if the Pi corrupts its' flash card and dies completely, the AVR will still<br>
be able to control the heating.<br>
<br>
Maybe I'm being too paranoid?<br>
<br>
Kevin<br>
<br>
> Kevin,<br>
><br>
> Out of interest what's the reasoning behind having the AVR rather than<br>
> getting the Pi to do it all directly ?<br>
><br>
> Cheers<br>
><br>
> Stuart<br>
><br>
> On 29/07/14 10:35, Kevin Wood wrote:<br>
>> Hi Bo,<br>
>><br>
>> I'm actually working on something quite similar at the moment for a<br>
>> second<br>
>> home that needs frost protection / monitoring remotely, in this case<br>
>> with<br>
>> oil fired heating.<br>
>><br>
>> My plan is a raspberry pi attached to an AVR which controls the heating<br>
>> system.<br>
>><br>
>> I'm thinking that the AVR can harvest temperature data from a couple of<br>
>> OneWire sensors, run the heating and hot water schedules and control<br>
>> relays that activate the heating system as required. It'll also have an<br>
>> RFM on the board for later integration with OpenTRV and, if I can<br>
>> reverse<br>
>> engineer it, the wireless oil level sensor on the oil tank.<br>
>><br>
>> R-Pi can host a web interface or, more likely in the first iteration,<br>
>> provide a mechanism to at least SSH into it and check everything<br>
>> remotely.<br>
>> Of course it could also do email notifications and SMS would be possible<br>
>> either via an internet SMS gateway, or just hang a GSM module off it<br>
>> with<br>
>> a cheap pay as you go SIM installed?<br>
>><br>
>> Does this premises have internet connectivity?<br>
>><br>
>> Kevin<br>
>><br>
>>> I was at local ham club last night at looked at their heating<br>
>>><br>
>>> So far i "THINK" its all electrical heating as there is no district<br>
>>> heating<br>
>>> installed, makes things a bit more easy since heat not used will go<br>
>>> back<br>
>>> to<br>
>>> the cylinder :-D<br>
>>><br>
>>><br>
>>> Next bit, there is one big room with 4 rads, which means one box should<br>
>>> control them all, the box will be central placed. Its mainly old timers<br>
>>> so<br>
>>> the less complicated the better, the rest of the rooms are one rad per<br>
>>> room.<br>
>>><br>
>>><br>
>>> Mostly @kevin but others might chip in, they have some kind of remote<br>
>>> control where they can send a text to turn stuff on and they would like<br>
>>> to<br>
>>> be able to turn on the heat remotely, how could we get to that?<br>
>>><br>
>>> the point is that when the house is locked heating should turn off<br>
>>> completely or run at 5degree to prevent frost issues. then either by<br>
>>> remote<br>
>>> command or when house is unlocked it should go to warm mode, there<br>
>>> would<br>
>>> be<br>
>>> no need to sense if its day or night or if people are in the room etc.<br>
>>> the<br>
>>> alarm will output a signal when its on/off<br>
>>><br>
>>> any ideas?<br>
>>><br>
>>> /bo<br>
>>><br>
>>> --<br>
>>><br>
>>> |||||<br>
>>> @(~Ô^Ô~)@<br>
>>> -------------oOo---U---oOo-------------<br>
>>> | |<br>
>>> | Bo Herrmannsen |<br>
>>> | |<br>
>>> | |<br>
>>> | "blessed are the "cracked", |<br>
>>> | for its they who let in the light" |<br>
>>> | Ooo |<br>
>>> |_________________ooO____( )________|<br>
>>> ( ) ) /<br>
>>> \ ( (_/<br>
>>> \_)<br>
>>> _______________________________________________<br>
>>> OpenTRV-dev mailing list<br>
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>>><br>
>><br>
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><br>
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><br>
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</blockquote></div><br><br clear="all"><div><br></div>-- <br><div dir="ltr"><pre><pre><span style="white-space:pre-wrap"> |||||
@(~Ô^Ô~)@
-------------oOo---U---oOo-------------
| |
| Bo Herrmannsen |
| |
| |
| "blessed are the "cracked", |
| for its they who let in the light" |
| Ooo |
|_________________ooO____( )________|
( ) ) /
\ ( (_/
\_)
</span></pre></pre><pre style="white-space:pre-wrap"><br></pre></div>
</div>