Relay board

plantwaterer

Plant Waterer v2.

A robotic plant watering system in two parts.

embeddedwaterer: Tinygo program for a microcontroller that waters on a fixed schedule. watererserver: Go program for rasberryPI that communicates with the embedded application to report stat and control remotely. Currently is a standalone parser that emits CSVs with stats data.

Big Features:

• Soil humidity sensors
• Multiple relays, allows different water circuits
• Read stats / update config remotely
• Webcam for monitoring, takes snapshots

Arduino

• Turns relays on/off for specified on/off periods.
• Takes commands, sends stats back over serial.
• Monitors humidity sensors, reports back to Pi

Future Plans

• Humidity based control, water when soil dries past certain threshold
• Store customization data in EEPROM

Raspberry Pi

• Currently just records serial data to disk for later analysis
• Takes webcam snapshot every 5 minutes

Future Plans

• Simple go service, hosts website.
• Polls Arduino via serial link on some interval. Keeps state of last values to show deltas.
• If Arduino resets, Pi monitor should automatically reset the water on/off durations if they’ve been changed.
• Awair integration to pull in room humidity/temp/co2 levels

Serial Link

More details on the linux side in the pi/README.md, and the hardware side in hardware/README.md In general, standard arduino serial at 115200 baud.

3-byte header, 4-byte request Request: CMD <command> <8bit number> <16bit number> Response: Echo command back. Stats is special and will then send stats followed by a terminator.

Commands

To send a command, echo over the serial link. echo -e 'CMD\x03\x00\x00\x00' > /dev/serial0

Stats Return:

Stats are continually sent via serial every StatsIntervalSeconds, default of 5.

{"now": 1485775,
"sensors":[
 {"id": 0, "d":[ 1, 37440, 2, 37376, 3, 37376, 4, 37440, 5, 37440 ]},
 {"id": 1, "d":[ 1, 37376, 2, 37440, 3, 37376, 4, 37376, 5, 37376 ]}
],"sections":[
 {"id": 0, "on": false, "next": 1555513, "last": 1296313, 
 "onTime": 50, "offTime": 259200, 
 "onAcc": 306, "offAcc": 1296007 }
]}

Notes:

• Number of sensors and length of history is determined at compile-time. It is limited by the memory capacity of your chip. More powerful chips can support more sensors and longer histories.
• All timestamps are relative to the local epoch, when the board was turned on.
• The data in sensors.d are pairs of (timestamp, value) from the analog input.
• onTime / offTime are current status values
• onAcc / offAcc accumulate time spent in on / off states over time

References

• https://github.com/huin/goserial
• https://www.digikey.com/product-detail/en/adafruit-industries-llc/997/1528-2003-ND/6827136
• https://tinygo.org/
• https://github.com/d2r2/go-i2c
• http://www.krekr.nl/wp-content/uploads/2013/08/Arduino-uno.pdf
• https://www.raspberrypi.org/documentation/hardware/raspberrypi/mechanical/rpi_MECH_3b_1p2.pdf
• https://www.youtube.com/watch?v=ioSYlxHlYdI (For solenoid board design)
• https://jlcpcb.com/ - Cheap PCB!
• https://www.ti.com/lit/ds/symlink/sn74hc595.pdf
• https://www.ti.com/lit/ds/symlink/uln2803a.pdf?