I’ve just received my Pololu U1V10F3 3.3v boost converter and 2xAA battery pack from HobbyTronics and it took no time to convert the veroboard from a coincell to the boost+batteries, I now have a stable 3.3v (from 3.31-3.37 recorded so far) and the sensors are working much better now.
I updated my code to store the voltage so that I know when the battery is dead and the boost can’t work, that meant moving the dewpoint calculation to the Raspberry Pi as it made my RF24 packet too large otherwise.
Oddly enough the stable voltage (or maybe the Pi’s new 3.10 kernel?) seems to have increased the range of the radio’s, I can get from the front of the house to the end of the garden (about 20m) no problem today.
Altitude: 32.15m, pressure: 14.86psi, temp: 22.91/23.37/24c, humidity: 46%, dewpoint: 11.66c, volts: 3.36v, date: Tue 03 Dec 2013 13:07:05