Hi everybody
I have now completed, some instructions on converting the UV on my webpage for the Oregon weather station
I have also put a link with some information on my idea
to use this with the 1 wire system
mick 
Hi Mick
Looks like the only sensor available in the USA us the UVR 128. Can I assume the only difference is the wireless freq ??
Thanks for the work on this project.
Cheers
MikeyM
Hi
Yes it will be only the frequency the idea is to replace the transmitter
using your extra temperature sensor, or hobby board moisture sensor seems the best bet
to interface with the 1 wire system
mick
Thanks Mick
MikeyM
Hi MichaelPT,
Can you post the link to your to you info re the 1-wire Solar. Thanks
Regard
Derek Chapman
Stokes Valley Weather
Lower Hutt, NZ.
A question about the instructions, if I may…
In the text below Fig 3 you write
I recommend using a screened cableit is important to measure out exactly 27 inches
I’m intrigued to know the significance of the 27 inches.
PS. I just got brave (reckless?) and took the back off a THGR928N (the only awkward bit is that the top pair of battery connectors are attached to the front so, once you have the screws out, you may need to apply a little pressure on those too to ease the case apart). Once apart you can see that the RH and T sensors (right at the bottom of the case) are well off the PCB (right at the top of the case) and connected to the PCB by thin wires. Mmmmm, I wonder that gives scope for a single ‘extra’ sensor to be the basis for two mods (thus making the most of the limited channels), and if the same arrangement exists in the other ‘extra sensors’, particularly the OS-THGR810, if that gives scope for ‘moded’ sensors on the WMR100 & 200 (for which there is not yet a ‘probe on a wire’ extra sensor)…
PPS. The reassembled THGR928N is working fine.
btw I found out the UVR128 is completely different internally than the UVR138. I took it apart, but haven’t had time to see if I can found the output of the sensor circuit to interface to the 1-wire network. If I make any progress I’ll post the results.
Cheers
MikeyM
Hi
To bring the UV1 in a acceptable range for calibration you need to place a resistor and the cable length gives a very small resistance
which works out really well and this gave me a standardised measurement
You can use any temperature sensor all you need to do is locate like you have done the thermistor and carefully remove the thermistor and connect
a screen cable to this then follow the instructions about the UV conversion,
UVR128 is my second choice for the modification have not got round to it yet,
is any chance you could take some close-up pictures of the circuit board and circuitry
mick
Hi MIck
I’ll try to get some pics of the UVR128 for you tomorrow as it’s getting late here tonight.
Cheers
MikeyM
Thank you.
Did you ever find out what the characteristics of the thermistor were on your dismantled probe?
FWIW my (uneducated) guess is that the RH sensor was perhaps resistance based too (looked like a very small white PCB with a zigzag ‘track’ on it). I should have thought to take a picture…
What I particularly fancy is a pyranometer (i.e. direct measure of solar radiation), so I was wondering if there might be any way of combining the Breitling “small PV solar panel as a solar sensor” idea with a modified OS sensor as the transmitter. I suppose that at least part of the trick would be in transposing a voltage range into a resistance range. It’s a long time since I did any electronics at all (and it wasn’t much then!)…
PS. I realise that 1-wire & labjack provide an easy root for voltage range handling, but getting a wired connection between where it’s best for the sensors and where the computers are would be a substantial undertaking…
Hi
I have a old extra temperature sensor unit which still has the probe attached to it, you can get the thermistors from Maplin Electronics supplies
Cannot remember spec as I am recouping from treatment when I get back I will measure the thermistor resistance
at 25c I will measure with the cable and its length and the thermistor on its own
Should not be a problem to get a replacement and calibrate through whether display
I did some work using a pv solar panel will do some more work when I get back I have just got to finish my snow sensor
lol for that rare stuff we sometimes get in the UK,
mick
Thanks for your reply Mick.
Best wishes for your recovery.