🌱💧 An open source DIY soil moisture sensor

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rbaron 9d352b2181 simple_timer nrf_sdk playground example. This uses the app_simple_timer library, which uses the high frequency clock for keeping track of time. In reality, we want to use the low frequency clock with RTC, since it's much more power efficient and we don't need high precision.		2021-02-20 10:17:10 +01:00
code	simple_timer nrf_sdk playground example.	2021-02-20 10:17:10 +01:00
hub	Uses a random, static MAC address	2021-02-13 10:18:05 +01:00
.gitignore	Adds a simple battery monitoring circuit and analog to digital measuring.	2021-02-14 10:59:18 +01:00
README.md	Notes on nrf52840 breakout	2021-02-16 18:09:24 +01:00
resources.md	simple_timer nrf_sdk playground example.	2021-02-20 10:17:10 +01:00

parasite

A low power soil moisture sensor based on the nRF52840.

TODO

Figure out how to calibrate the ADC when running from different voltages, as the battery discharges
Experiment with different TX power / battery tradeoff. Since we'll be deepsleeping most of the time, maybe we can get away with a lot of TX power.
Implement deep sleep
Measure current in deep sleep
Measure current in operation (ADC + BLE adversiting)
Test with a range of 2-5V input. Disconnect from USB and monitor using a serial post. Use the bench power supply to power Vcc with variable voltage. DO NOT CONNECT VCC FROM THE USB-TO-SERIAL BOARD!*
Test with a coin cell
Implement ADC for battery monitoring
Figure out a way for people to configure the device with a custom name. Idea: BLE service (this is what my hacked xiaomi temp sensor does)
Figure out how OTA works (if at all) over BLE
Design new board using the nrf52840 (E73-C) instead of esp32

Implement battery level monitoring
Implement BLE advertising with moisture
Implement ADC for the parasitic capacitor; check out air/water range (using protoboard)
Simple PWM square wave generator
Hook square wave generator to the protoboard sensor circuit
Make the protoboard sensor work