The flower sensor firmware allows you to create a soil moisture sensor with configurable, rich functionality like additional temperature or humidity sensors, a custom reporting interval. The firmware uses a capacitive measurement based on the following free open-source schematics.

⚠️ THIS FEATURE REQUIRES THE PREMIUM VERSION

Schematics

https://github.com/deaxx/ptvo_flower_multisensor

https://modkam.ru/2020/08/03/sensor-vlazhnosti-pochvy-zigbee/

Limitations

The firmware based on the regular PTVO firmware except for the following:

• The firmware contains a limited set of sensors that are applicable for battery-powered soil moisture sensors.
• It cannot work as a router.

Unique features

• It supports various chips (CC2530, CC2652, CC2651).
• You can disable unused functions.
• You can create your own schematics.

How it works

While measuring soil moisture, the firmware generates a high-frequency signal of 2 MHz via the “Clock” pin. The schematic transforms it to an analog value that represents a relative soil moisture.

Firmware configuration

1. Start FirmwareConfigFlower.exe in the program folder.
2. Select the “PSM” device type.
3. Add a soil moisture sensor at least.
   • The sensor pin should allow reading analog values.
   • The “CLK” (clock) pin should support the PWM feature.
4. Add other sensors.
5. Configure default reporting interval on the “Expert” tab. The firmware will poll all sensors before sending a periodic report. The chips sleeps between periodic reports and consumes minimal energy.
6. The optional “External wake-up” button on “Input 1” allows you to reset the device (10 seconds long click) or send a periodic report (short click).

Additional options

Scale (A), Shift (B) – These parameters allow you to apply a simple formula and adjust the measured value to suit your environment.

Reported_Value = A x Measured_value + B

A – any single precision float value
B – single precision float value in the range from -100 to 100.

The reported value should be within the range of 0 to 100. If the calculated result falls outside this range, it will be adjusted to the nearest boundary.

Power saving (energy consumption)

1-hour statistics

Test duration: 3600 seconds
Number of reports: 1
Current (max, transmitting): 18050 uA
Current (avg, sleep): 1.96 uA
Estimated battery life:
Battery life (1 x CR2032 @ 240 mAHr): ~485 days
Battery life (2 x AAA @ 1200 mAHr): ~2400 days
Note: it is the theoretical calculation. It is important to check a current leakage in your device before using it with a battery and protect electronic components on your device from impact on the environment (high relative humidity, oxidation of contacts, etc.). I recommend using urethane aerosol spray for it.