Lesson 011 – Soil moisture sensor
You need:
iTriangle online, soil moisture sensor, LED display 8x8
|
|
|
|
|
|
Soil moisture sensor |
Buzzer |
8x8 LED display |
Introduction:
The humidity sensor measures the current passing through individual electrodes. This current is dependent on the humidity and chemical composition of the monitored environment. The more water (ions) present in the environment, the more conductive the environment. A humidity sensor detects small currents in mA and low DC voltages up to 3.3V. However, weak electrolysis also takes place in the monitored environment. A very small amount of corrosion will occur on the electrodes, which will accumulate salts over a long time. The pH of the environment may also change over a longer period because of the chemical reaction. To prevent these phenomena from happening in long-term measurements, do not measure continuously for long periods and limit measurements only to a few per day.
Task:
Learn how to detect moisture in the soil of a plant and understand the principle of this measurement. Create an indicator for a plant that lets you know when more it needs more water.
Tutorial:
- Construct a simple stand with iTriangle online and connect the sensors and components as pictured below. Connect iTriangle online and upgrade its firmware by following these steps.
- Choose an object you want the PIR sensor to detect.
- Start the program.
- Four things may happen:
- If the water content is high, a happy face will show on the LED display
- If there is just enough water present, a neutral face will show on the LED display
- If there is not enough water in the soil, a sad face will show on the LED display
- If the soil is too dry, a sad face will show on the LED display and the buzzer will make a sound
The program will run for 60 seconds until "End of program" is shown on the LED display. The length of the program and values for when different faces are shown on the LED display can be changed.
Extra mile:
Examples of good practice:
Technical notes:
Over time, corrosion will occur and the electrodes will lose their shine. To prolong the sensor’s functionality, clean and dry the electrodes thoroughly after each experiment. Do not use the sensor to measure the conductivity of alkaline or acidic liquids.
Žádné komentáře