Is it time to water the plant?
This activity is an introductory way to use sensors, physical computing and a program on a TI calculator to determine if a plant needs to be watered.
The program reads the soil moisture value from the moisture sensor (through a TI-Innovator Hub) and compares the value to thresholds for "dry soil". If the moisture sensor value is lower than the dry threshold, the program prints a message to the screen and changes the color of the RGB LED on the TI-Innovator Hub to RED.
If the value is higher than the dry threshold, the program prints a different message to the screen and changes the RGB LED color to GREEN.
The program can be extended to have a "need to water soon" message with a YELLOW light if it is between two set points.
This simple check of the soil state can lead to some additional questions to discuss when doing this activity.
- Instead of watering everyday at a fixed time, we should use this to only water when needed. Maybe we are watering too much? Or too little?
- Different plants will use the water at different rates. We could have different watering times based on how dry the soil is.
- Do different soil types hold water differently? How does the outside flower bed differ from the indoor plants?