Jhansi Sunkerneni
Published September 2020
One must ensure that they have the necessary materials before they begin working on building the soil moisture sensor. I got the materials needed from the website: sciencebuddies.org. I highly recommend getting additional resistors and LED bulbs as they tend to fuse out/burn out very easily. You will need the following items for each team: breadboard, a4011 NAND gate, jumper wires, 10 MW resistors, 470 MW resistors, LED bulbs, 100kW resistors, and a 5 Volt battery.
Soil Moisture Sensor Reflections
I was able to complete this unit with students, as students are back in the classroom after Covid. Here is a summary of my reflections: Students who didn’t finish this project got help from teams that completed early. 80% of the students were able to complete building and testing the soil moisture sensor. Some of the challenges that students faced are listed below: Short circuited the snap connector and the battery. Had to cut, strip the wire, and twist the wires before inserting it in the breadboard a second time. Made wrong connections, as they didn’t follow the instructions carefully. Fixed the problem by re-reading the instructions and following the instructions carefully. Using the wrong resistors in the circuit. Realized later, that the resistors that need to be connected to the soil must be the 100K Ohm resistors. The wires were loosely connected to the breadboard. Corrected the problem, by ensuring that the wires were connected securely. The snap connector was not connected correctly. Figured out the positive and the negative markings on the battery, and made the correct connections. The LED bulb didn’t glow due to polarity (placed incorrectly in the breadboard). Fixed the problem, by making the correct connection of the leads.
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