n96gy temperature sensor

[notlongnow]

hi all,
have a maplins n96gy .
the outside temperature sensor has packed in. just gives a constant reading . Stays the same no mater the temp is.
anyone know where I can get a replacement sensor from.
have looked about on the internet and so far not found one .
thanks all.

[sfws]

1) You should have posted in the Fine Offset sub-forum, not the Davis one. Experts on the Fine Offset like AllyCat are more likely to see your post in correct place.
2) Maplin used the same reference for different designs of the transmitter, all with a black case for the indoor console, and I believe the way that temperature was measured varied, in some versions being combined with humidity measurement and not in others.
3) look in viewtopic.php?f=13&t=2685 where there are photos of inside these units, and see if you can work out which is your design. My Maplin model N96FY used a thermistor I believe, but I replaced it with a Chas Olson Fine Offset station, and I have no real knowledge of the circuit boards.

4) Once you have identified the part required, there are electronics firms that sell standard components like these sensors, and also firms that sell replacement transmitters as a whole unit. You don't let on whether you are UK based, because the Chinese firm Hope Microelectronics Ltd who made original components no longer has a UK agent

5) If you import a transmitter from outside UK, quote what frequency your unit uses (it is probably 433 for a Maplin unit) and what protocol your unit uses. This latter depends on when you bought it (because the protocol for transmission changed. One protocol used is On-Off-Keying and another protocol used is Frequency-Shift-Keying. A third possible protocol is Pulse Width Modulation)

[Super-T]

How about take the transmitter apart and check for moisture or foreign bodies?

[notlongnow]

hi all,
thanks for the reply.
has been striped down and cleaned out and all looks good .
I think its the thermistor but I could not find type number .
will see if I can find one that is the right one.

thanks again all

[AllyCat]

Hi,

Yes, it's probably a thermistor in the External transmitter. I did actually characterise one some years ago, but the data is on a different computer that may take some time to find. I think it might have been 20k ohms at 25 degrees C, which is not particularly common. If you can find a thermistor with a particularly "steep" characteristic then you might be able to synthesise a replacement by adding series and/or parallel fixed resistors.

However, this may seem a stupid question, but is the Wind Vane reporting correctly ? (I've not checked that particular Maplin number but the vast majority did have a vane). The reason I ask is that the "transmitter" may use the same ADC to measure the Wind Direction and External Temperature, and the Vane cable/connections can severely upset the temperature measurement (it's probably one of the main reasons for the notorious "Fine Offset Spikes"). The ADC is also rather "unconventional", but you may find a helpful description very many years ago (about 2010) by "Gina" in one of those "photos...." Sticky threads* in the Fine Offset section. But that problem did eventually disappear in the WH308x stations' firmware (that was later ported to the more recent OOK versions of the WH108x / Maplin). Which gives me second thoughts whether they still use(d) a thermistor. Temperatures are now more commonly obtained from the Humidity Sensor, if it uses a "data bus" (3-4 wire) rather than analogue (2 wire) connection.

* EDIT: Or it might not have been a "sticky", but a very long thread about "Temperature Spikes", particularly associated with an electric fence, in about the same year!

Cheers, Alan.