The basic idea of this project is to convert a $3-4 solar light found at Lowes and Home Depot hardware store (here in the US) into a wireless remote sensor node. The node will utilize an MSP430G2553 MCU and a nRF24L01+(w/ spirilis library) wireless module to send light intensity (photoresitor that came with solar driveway light), soil moisture (design from http://gardenbot.org), and soil temperature data (10k thermistor coated in silicon) wirelessly from my garden to another MSP430G2553 and nRF24L01+ sitting on top of a Raspberry Pi.
I taught myself Eagle Autocad and created a schematic/board to replace the stock board inside the solar light. My board utilizes a Texas Instrument TPS61097 (free sample) which converts the 1.2v from the batter to 3.3v to power the MSP430. Version 1 of the board is shown below with just the power circuitry populated (Photo 6).
I put a jumper wire on the TPS61097 between the EN and VIN because I wasn’t able to get the bypass switch (Page 16 of the schematic http://www.ti.com/li…tps61097-33.pdf ) to work correctly. I had 200k resistors on R1 and R2 (actually 2x100k 1% in series each…didn’t have any 200k on hand) which didn’t work (bypass switch stays on) so I jumpered EN and VIN and now get the full 3.3v. I would like to get this bypass feature enabled. Any ideas where I am going wrong here? I assume the resistor values are incorrect for the 1.2v battery.
For more detail: Solar Driveway Light to MSP430 Wireless Sensor Node