On Monday, we completed the first part of the Data Acquisition’s activity – to calibrate a Milone eTape Liquid Level Sensor and display the water level on an LCD screen.
Here’s the calibration curve that we plotted using Microsoft Excel after recording down various data points during the calibration process.
From the graph, we observed that when the water level increases, the resistance value (output) decreases.
After the calibration, we proceeded to the second part of the activity which had us design a circuit to sound a buzzer when the water level exceeded a certain threshold.
How did we do it?
First, we used Fritzing to plan out the schematic diagram for our circuit as shown below:
This helped us to plan, design and visualize the circuit easier before embarking on physically wiring the circuit.
We also did some research on the Arduino code which would generate a siren-like sound in the buzzer. We referred to this link for a tutorial on how to generate the siren-like sound: http://www.electroschematics.com/9548/arduino-siren-sound-alarm/
It was quite frustrating to get the buzzer working as we had to hold the buzzer wires in place which were quite flimsy as they did not come with proper male connectors, and instead just bare wires at the ends. Hence, we had to make sure it was always connected during testing, but it got disconnected very frequently. Here’s a short video clip of our result: