AlphaLima rightly pointed out that an ESP8266 wifi module would eliminate the need for one of the wireless modules as Kobo's have builtin wifi. Only problem for my application was that the average current consumption of an ESP8266 was too high.
Enter the the ESP8266 ESP-12f module. This has a re-designed RF section and thus runs more efficiently. I bought both 12f and 01 modules and can report that indeed the 12f really helps the battery situation. mA testing at 5Volts and with the modules on a breakout board (which has LED state-indicators): 01 = *Average mA was 138mA and RF section ran hot, 12f = *Average mA of 84mA and RF section ran cool (* Average mA was read by measuring in front of a 47,000uF smoothing capacitor).
So good news if you want to separate out your sensors from your screen (Kobo)
Since 2006, owned and maintained by PostFrontal S.A.S. di Giuliano Golfieri & c. - VAT ID: IT05264240960 THIS WEBSITE ONLY USES FUNCTIONAL COOKIES Privacy & Cookie Policy