[OpenTRV-dev] Useful IRC chat re H-bridge etc

[Damon Hart-Davis]

Hi,

Yes, I'm doing that already.  Looks much more accurate than the datasheet suggests.

The internal temperature measurement is pants though.

Rgds

Damon


On 17 May 2013, at 11:37, Mike Stirling wrote:

> That's a nice solution. Also don't forget that for applications where Vbatt == Vcc the battery voltage can be measured efficiently with no external components on AVR.
> 
> ----------------original message-----------------
> From: "Damon Hart-Davis" EMAIL ADDRESS HIDDEN
> To: "Closed list for developer discussions" EMAIL ADDRESS HIDDEN
> Date: Fri, 17 May 2013 11:15:48 +0100
> -------------------------------------------------
> 
> 
>> Thanks.
>> 
>> Damon
>> 
>> 
>> On 17 May 2013, at 11:05, Stuart Poulton wrote:
>> 
>>> The following from jcw is also of interest
>>> 
>>> http://jeelabs.org/2013/05/17/zero-powe-battery-measurement/
>>> 
>>> On 16 May 2013, at 22:30, Damon Hart-Davis wrote:
>>> 
>>>> DHD20130516: Useful IRC session about H-bridge direct motor drive,
>>>> including outline schematic from Mike (only needs two digital lines to
>>>> drive it) and notes about current monitoring and supply management.
>>>> 
>>>> 
>>>> http://www.earth.org.uk/OpenTRV/circuitFragments/MS20130516-hbri
>>>> dge-2wire.png
>>>> 
>>>> 
>>>> http://www.earth.org.uk/OpenTRV/circuitFragments/MS20130516-hbri
>>>> dge-2wire.txt
>>>> 
>>>> The neato thing there may be that Schottky diode + small super cap may
>>>> isolate the AVR from motor-induced voltage sags and with care may allow AVR
>>>> to maintain software RTC running while main batteries are swapped out. (I
>>>> can put TMP112 and RFM22 on other side of that diode if need be to get current
>>>> draw down to 1.3uA.)
>>>> 
>>>> Plus Bo has made enough space to possibly squeeze the actual H-bridge
>>>> components in! B^>
>>>> 
>>>> Rgds
>>>> 
>>>> Damon
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