[OpenTRV-interest] Tinkering kit / battery powered board

Tue May 20 22:38:04 BST 2014

Thanks, Damon. See below.

On 20 May 2014 20:17, Damon Hart-Davis <EMAIL ADDRESS HIDDEN> wrote:

> Hi,
> On 20 May 2014, at 19:37, Alasdair Macdonald <EMAIL ADDRESS HIDDEN>
> wrote:
> > Today I purchased a plastic box from Maplin, cut some holes in it, and
> put one of my 2 OpenTRV controller boards inside. It's powered from a
> battery caddy similar to that mentioned by Damon in an earlier e-mail.
> >
> > As far as I can tell, it's working as intended. There are a series of
> flashes from the red LED when I make the battery connection (boot up
> flashes), and there are also flashes when I press buttons.
> >
> > I've looked over the user guide.
> >
> > Q1. Now I have one board is connected to my PC semi-permanently,
> uncased. And one board in a black plastic case, with battery power. To what
> extent will the occupancy / light sensor fail in the cased board? (I don't
> even know what the light sensor is; is it the thing marked "LDR”?
> Warning: black plastic boxes may be carbon-loaded and block RF.

95% of the antenna is outside the box.

> Yes, the light sensor is the LDR.  If it doesn’t get enough light it’ll
> think that it can set back the temperature a bit because you’re in the
> dark.  But no huge changes.  if you update to the latest code then you can
> see regular status reports of light level.
I might drill a hole near the sensor.

>  >
> > Now that I have a Conrad valve attached to a radiator, and having worked
> our way through the pairing issue that I mailed about yesterday, I can see
> data from the Conrad actuator in my console. Stuff like:
> >
> > 1146:30:73 FHT8V TX
> > 1148:26:73 FHT8V TX
> > However, I don't see anything from the battery powered board being
> received and spewed out to the console.
> If you want a board to receive you’ll need to put it in hub controller
> mode with “C 2” (or a larger number) on the CLI; it can pick up and log
> transmissions from the other unit (if I’ve understood you correctly).
Done. I typed "C 2" and this is now present in the output, but I don't see
any messages from the battery-powered board. Typical console messages are:

1308:54:84 FHT8V TX
=W0%@23C2;T21 48 W255 0 F255 0 W255 0 F255 0;S21 10 21 cff;C2;HC93 74

and they are arriving quicker now, at ~1 minute intervals.

> >
> > Hence:
> >
> > Q2. Should I see anything from the battery powered board being received
> and spewed out to the console?
> Not unless the PC board is in hub/controller mode.  And I suggest you
> power it via USB or the FTDI cable rather than batteries.

Board #1 is connected to the PC / FTDI cable; that's the only console that
I have, and that's the console that I thought I might see new messages on.
But I don't.

> And make sure both aerials point in the same direction, preferably
> vertically/upwards.


> >
> > I think I can figure out from the user guide how to send messages to the
> Conrad valve to get it to open (I just need to set the controller mode and
> temperature knob to appropriate settings, right?); however the user guide
> says that the temperature knob goes up to around 23 degrees and currently
> my Oregon sensor reports 24.5 degrees.
> Boost / quick heat mode gets you another 5C at least for testing purposes!
I put board #1 into Boost and got 99% open on the Conrad
Valve (subsequently I saw it go down to 80% and now the test is over I put
it back to Warm and the Valve is now at 0%):

1314:42:88 FHT8V TX

Remote call for heat on

Boiler on, s left: 120
=B100%@23C3;T21 54 W255 0 F255 0 W255 0 F255 0;S26 10 21 cffO;C2;HC93 74

Boiler on, s left: 120
=B100%@23C3;T21 55 W255 0 F255 0 W255 0 F255 0;S26 10 21 cffO;C2;HC93 74

1316:38:88 FHT8V TX
Boiler on, s left: 120
=B100%@23C0;T21 56 W255 0 F255 0 W255 0 F255 0;S26 10 21 cffO;C2;HC93 74

> >
> > Uh, maybe here's another question.
> >
> > Q3. How many devices are "paired"? Previously I paired the Contrad
> actuator with board #1 (connected to PC); and I set the House Code on that
> board (manually). Should I follow a procedure to pair controller #2, and /
> or set its House Code?
> If you want the control a second valve then put its house code into a
> second OpenTRV unit.  One unit can also/instead control a boiler.

The Conrad documentation states that when they supply a "set", that devices
are pre-paired. Does this mean that Conrad don't anticipate zoning, that
all devices and the controller share one House Code?

I'm confused by how signals are recognised by each device.

The boiler controller may receive messages from many sensors that ask it
switch on the boiler, if necessary. For this to happen, does the the boiler
controller require a matching House Code?

So let's say that we have 2 rooms, 2 sensors, and 2 valves. Let's say that
right now that we ONLY want one of these 2 rooms to be heated. The sensor
in room #2 sends an instruction for the boiler to fire up, if necessary,
and it sends an instruction to valve #2 to open to more than 0%.

So how does the message from sensor #2 to valve #2 not also cause valve #1
in room #1 to open? If the answer is, "because room #1 and room #2 use
different House Codes", then how does the boiler board know which House
Codes to permit, given the possibility of receiving signals from a

I still don't have ANY House Code on board #2 (the battery powered one).
Should I put the jumpers back on, connect to PC, set the same house code /
a different house code, then put it back to being battery powered? I think
if I understand the House Code stuff better I'll know how I should
configure this board.

In an earlier e-mail you wrote that "led and series resistor between the B
and GND screw terminals" would allow the supposed boiler controller to
indicate if it was supposedly on or off. Can you elaborate for someone that
isn't an electronics hobbyist what parts I can obtain from Maplin (10
minutes walk from home)?

> >
> > (The board that is connected to the PC is currently flashing about once
> every 2 seconds. User Guide states "Essentially the more flashes and the
> more often the flashes, the more the room will be heated". But the Conrad
> Valve is still at 0%. It's been like this for some time; should I be seeing
> something on the Conrad vale (other than "0%")?
> My guess is that you are in WARM mode (with status lines starting “=W”
> appearing about one per minute, but that the target temperature is below
> room temperature so that valve doesn’t have to open.
> Hold down the BigRedButton until you get into Boost / Quick Heat mode
> (“=B”) status lines, and the valve should open, assuming that your room
> does not get above 28C or thereabouts.
Yep, I'm good on that now, thanks. Still having a bit of difficulty with
recognising the number of flashes...
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