What even are the features

[tomblanch118]

Essential:
-Connect to one (or more?) platinum thermocouples (PT100/PT1000?).
-Transmit data to some kind of logging/visualisation system - range?
-Configurable intervals and thresholds
-Visual indicator for success
-Work from easily obtainable batteries (AA/AAA)

Good to Have:
-Log data internally to some flash memory or an SD card (easier for humans?)
-Timestamp data

• Connect to WiFi /eduroam

[tomblanch118]

3.3v boost IC:
https://datasheets.maximintegrated.com/en/ds/MAX1722-MAX1724.pdf
150mA limit might be a concern but unlikely
looks simple

alternative is TPS61030
http://www.ti.com/product/TPS61030/technicaldocuments
more complicated and have to work out our own inductor/resistor/cap values
much higher output current

[tomblanch118]

high-side switch for switching power to 31865 RTD module?
http://www.ti.com/lit/ds/symlink/tps2041b.pdf

TPS2041B? 70 mOhm, looks plausible