[OpenTRV-dev] DS18B20 with Arduino

[Damon Hart-Davis]

Hi,

Thanks for suggestions!

As long as we connect it up plausibly, with a 4k7 pullup, then we can probably fudge it in code later.

I would check it at each reset, which would generally be at power-up.

Rgds

Damon



On 19 Sep 2013, at 13:12, Kevin Wood wrote:

>> its more to give Damon tips on how he could approach it.... i'm more the
>> hardware guy that do the pcb's
>> 
>> but yes tmp112 is a 2 wire.... sounds like a plan to me... ie not power up
>> tmp112 and poll data oin that DS is connected to... should be fairly quick
>> too
> 
> Yes. It would only have to be done once when a battery is inserted. After
> that the AVR can remember its' config. Could even save it to EEPROM so it
> never has to be done again, I suppose. Unless you only ever have a single
> device on the OneWire bus, you need to do this anyway, to learn the
> addresses of all connected devices.
> 
> I suppose I should acquaint myself with the current design. Been a bit out
> of the loop recently.
> 
>> 
>> as a SMALL ps... you or anyone else knows where to get hands on solder
>> dispensers ? will not mind a used one...
> 
> I'm afraid not.. I tend not to venture too far away from through-hole
> devices. I don't need such steady hands then. ;-)
> 
> Kevin
> 
>> /bo
>> 
>> 
>> 
>> -----Oprindelig meddelelse-----
>> From: Kevin Wood
>> Sent: Thursday, September 19, 2013 1:56 PM
>> To: Closed list for developer discussions
>> Subject: Re: [OpenTRV-dev] DS18B20 with Arduino
>> 
>> Hi Bo,
>> 
>> OK. Not that familiar with the tmp112 but I believe it has a 2 wire serial
>> interface? If you set the clock pin inactive initially at power-up and
>> polled the data pin using the dallas 1 wire protocol to see if any OneWire
>> devices respond, then fall back to the tmp112 protocol if not, I guess
>> that would probably work?
>> 
>> Kevin
>> 
>> 
>>> Hi
>>> 
>>> Damon might not have mentioned or i have not seen that he has
>>> 
>>> but we would like ideas on how to detect if we have a DS18B20 or TMP112
>>> fitted
>>> 
>>> the TMP is very low power and great res. but also a pain in the arse to
>>> fit
>>> even with manual pick and place..  thou i'm getting close... just need a
>>> solder dispenser and i'm good for it
>>> 
>>> /bo
>>> 
>>> -----Oprindelig meddelelse-----
>>> From: Kevin Wood
>>> Sent: Thursday, September 19, 2013 1:26 PM
>>> To: Closed list for developer discussions
>>> Subject: Re: [OpenTRV-dev] DS18B20 with Arduino
>>> 
>>> It seems that the code I used was derived from this:
>>> 
>>> http://www.siwawi.arubi.uni-kl.de/avr_projects/tempsensor/
>>> 
>>> There's no mention in the code or the web site of any license or
>>> permission under which it may be used, unfortunately. At the time, that
>>> didn't bother me, of course...
>>> 
>>> It's not that complex, and I have onewire devices, so I could attempt to
>>> "white room" myself and write something?
>>> 
>>> Kevin
>>> 
>>>> Thanks, that would be helpful!
>>>> 
>>>> Rgds
>>>> 
>>>> Damon
>>>> 
>>>> 
>>>> On 18 Sep 2013, at 19:25, Kevin Wood wrote:
>>>> 
>>>>> I've been using OneWire sensors with an AVR quite a bit. I'll have a
>>>>> look at where the code I used came from. Can't remember if it was
>>>>> home-made, pinched from somewhere or a combination thereof!
>>>>> 
>>>>> Kevin
>>>>> 
>>>>> On 18/09/13 18:09, Damon Hart-Davis wrote:
>>>>>> Hi,
>>>>>> 
>>>>>> Bo: following our earlier discussions
>>>>>> 
>>>>>> With a little research I think it should be possible to make the V0.2
>>>>>> work with DS (when running on 3.3V) or TMP, detected at run-time if
>>>>>> need be, though there are a number of trickinesses, especially with
>>>>>> timing because the DS is slow.
>>>>>> 
>>>>>> But I have not yet found a sensibly-licensed 1-Wire library for
>>>>>> Arduino/ATMega (ie *with* some sort of licence that isn't GPL and
>>>>>> pref
>>>>>> is BSD or Apache or MIT or similar), so might have to reverse
>>>>>> engineer
>>>>>> something.
>>>>>> 
>>>>>> In any case it's not a trivial bit of work, but not insurmountable
>>>>>> either.
>>>>>> 
>>>>>> Rgds
>>>>>> 
>>>>>> Damon
>>>>>> 
>>>>>> 
>>>>>> _______________________________________________
>>>>>> OpenTRV-dev mailing list
>>>>>> EMAIL ADDRESS HIDDEN
>>>>>> http://lists.opentrv.org.uk/listinfo/opentrv-dev
>>>>>> 
>>>>> _______________________________________________
>>>>> OpenTRV-dev mailing list
>>>>> EMAIL ADDRESS HIDDEN
>>>>> http://lists.opentrv.org.uk/listinfo/opentrv-dev
>>>>> 
>>>> 
>>>> _______________________________________________
>>>> OpenTRV-dev mailing list
>>>> EMAIL ADDRESS HIDDEN
>>>> http://lists.opentrv.org.uk/listinfo/opentrv-dev
>>>> 
>>> 
>>> 
>>> _______________________________________________
>>> OpenTRV-dev mailing list
>>> EMAIL ADDRESS HIDDEN
>>> http://lists.opentrv.org.uk/listinfo/opentrv-dev
>>> 
>>> _______________________________________________
>>> OpenTRV-dev mailing list
>>> EMAIL ADDRESS HIDDEN
>>> http://lists.opentrv.org.uk/listinfo/opentrv-dev
>>> 
>> 
>> 
>> _______________________________________________
>> OpenTRV-dev mailing list
>> EMAIL ADDRESS HIDDEN
>> http://lists.opentrv.org.uk/listinfo/opentrv-dev
>> 
>> _______________________________________________
>> OpenTRV-dev mailing list
>> EMAIL ADDRESS HIDDEN
>> http://lists.opentrv.org.uk/listinfo/opentrv-dev
>> 
> 
> 
> _______________________________________________
> OpenTRV-dev mailing list
> EMAIL ADDRESS HIDDEN
> http://lists.opentrv.org.uk/listinfo/opentrv-dev
>