Solar Powered, pH/ORP/Temp sensor

This Sensor will help you to monitor the main parameters of your swimming pool.

To avoid replacing the batteries so often, a rechargeable Li-Ion 16850 battery is charged by a small 5V, 100ma, 9x6cm solar panel on top of the case.

Readings are done on every 12min. 5V step-up is connected to D3 pin in order to activate the sensors only during reading cycle.

By using the nice Ceech board, some nice features are available:

• Socket for nRF24L01 and ESP8266
• LTC4079 Charge IC: Quiescent current while charging is 4µA, Ultralow battery drain when charged IBAT < 0.01µA , power source can be any small, 5V - 20V solar cell.
• TPS63031, a 3.3V DC-DC buck-boost converter. low power consumption, efficiency is over 90%, power-save mode, etc.
• 3amp 30V n-channel MOSFET (to switch on the 5V step up and power the pH and ORP sensors).

Sensors

• pH: SEN0161from dfrobot
• ORP: 3556 from phidgets (with 1130 adapter)
• Temperature: DS18B20 waterproof

Pin Setup

• A0 - Battery voltage (internal at Ceech's board)
• A1 - ORP sensor (analog)
• A2 - Solar Cell voltage (internal at Ceech's board)
• A3 - pH sensor (analog)
• D5 - One wire bus (for Temp DS18B20 sensor)
• A6 - Charge current (internal at Ceech's board)
• A7 - /CHRG signal from LTC4079 (internal at Ceech's board)
• D3 - MOSFET gate (internal at Ceech's board)
• D7 - CE (internal at Ceech's board)
• D8 - CSN (internal at Ceech's board)

The housing is made by 20cm of PVC 100mm tube, with two caps + rubber rings:

(and some rocks for perfect balance) ;-)