National Free Flight Society

SEN 3113

  1. SEN 3112 Dick Wood thermal detector info provided
  2. An approach to find the right thermistor if not known
  3. THERMAL detector if you can’t fix your Wood meter
  4. Another possible source

SEN 2112 Dick Wood thermal detector info provided

From Peter Brocks
Roger and Dick Ivers,

The Thermistor for the Woodmeter is from
Digi-Key KC012G-ND, Glass Encapsulated, 50k Ohm, made by Amphenol Thermometrics
The Thermistor Cable is a Radio-Shack Speaker Wire, 2-conductor, stranded, 22AWG
Peter Brocks

Editor’s Comment .  In Peter’s piece above there is a key piece of extra information – 50 ohm .. And the electronics in the “Wood Meter” will match that value and possible some other characteristics.

So the best approach is to get the one Dick used as provided by Peter.
Next best is use that additional piece of information -50 ohm to find another with similar Characteristics.
Those failing try the suggestion from Antony below to find the right value by experiment.


An approach to find the right thermistor if not known

From Antony Koerbin
Hi Roger
Dick Ivers had a question re thermistors
I think what he needs to do is use a variable resistor in place of the thermistor and adjust the resistance until it displays 25 celcius in a space he has heated to 25 celcius (77 f). If he doesnt have a suitable variable unit then just try a few resistors. 2k 4k 10k are common.
So if in a room that is 25C the unit needs a 2k ohm resistance to show 25C (or close enough) then that is the thermistor he needs.
Close enough is fine as its not the exact temperature but the change in temperature we are looking for

Antony Koerbin


THERMAL detector if you can’t fix your Wood meter

(build your own)
Alan Abriss
In regard to finding a thermistor I once used the temperature sensor from a kitchen instant read thermometer.  It was easy to wire up and did a good job of pointing out the presence of rising air temps.

Alan Abriss


Another possible source

(contact  someone who is building one – such as  )

From Frank Menanno
Roger my little brother Neal Menanno is building a thermal detector that uses a sensor that Dick might be able to use, you might have him get in touch with Neal
Frank Menanno


There are other Thermal detection devices also such as Joni Sevev’s WarmLift, the App is in the AppStore and Google play