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[wxsig] T238+ sensor list

Robert McGwier rwmcgwier at comcast.net
Sat Mar 18 19:18:12 UTC 2006

George wrote:
> Folks,
> here is a list of sensors to build a complete weather station based on 
> T238+ modem2
> Sensors verified to work with it, by George Chrysostomou, SV2DOF
> 1     Anemometer (Wind speed/direction)
>    TAI-8515 V3 Wind Instrument from AAG Electronica
>     Works OK, by default.
> 2     Humidity / Temperature
>    TAI-8540 1-Wire Humidity Sensor from AAG Electronica
>     Works OK.
> 3     Rain-Gauge
>    RG1-R1-A from Hobby-Boards. It is a RAINEW tipping bucket rain 
> collector from RainWise, modified by Hobby-Boards with the addition of 
> a 1-Wire Dual Counter DC2.5-R1-A (DS2423).
>     Works OK, ONLY if both counter inputs A and B are connected together.

I have the Davis Rain Gauge modified using the AAG modification to 1 
wire.  Does this work with the T238+?
> 4     Barometer
>    *     B1-R1-A from Hobby-Boards. It is a Bray design, based on 
> Motorola/Freescale MPX4115A sensor, as modified by Tim Bitson. It has 
> a single instrumentation op-amp (INA-122) with fixed gain to x10. 
> Needs at least 14Vdc for operation.
> Works OK, ONLY if Vref is set to MPX4115A's Vout @ 931mBar (5.1V 
> P.S.), 3.789V and gain is adjusted to 15.10852 (actually to 15.10333) 
> by adding a resistor of 39k in parallel of R1(=40.2k)
>    The following baro sensor tried but DID NOT WORK
>    *     TAI-8570 1-Wire Pressure Sensor from AAG Electronica
> Does NOT work. It is found and read but the indicated value is 
> erroneous. It has built-in calibration table but needs special 
> procedures, not currently supported, to read the correct calibrated 
> pressure value.

Using OWW and AAG's weather station this pressure sensor does calibrate 
nicely and thereafter it is accurate.  Once the procedure for doing this 
calibration is designed,  this instrument will be worth using.

> 73 de George, SV2DOF


AMSAT VP Engineering. Member: ARRL, AMSAT-DL, TAPR, Packrats,
Laziness is the number one inspiration for ingenuity.  Guilty as charged!

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