Week 6: Electronic Inputs
For this week, our assignment was exploring capacitors and other input sensors.
Capactive Sensor
Capacitors are found in a large range of consumer electronics for its ability to detect the distance and overlap between two sets of parallel plates.
For this part of this assignment, I was inspired by BFF heart necklaces.
I made a capacitor sensor that would detect the distance between the separation of the two halves.
In my initial iteration of the heart halves, I treated the two sections as independent entities.
However, I realized that calibrating the capacitor would be challenging whithout securing the halves in parallel alignment in some way.
I CAD-ed a small hole for a nut to fit into on the back of the halves so that I could fix the heart onto a slider.
In this setup, I calibrated the heart-slider capacitor based on the distance between the two halves:
Distance (mm) |
Output Trial 1 |
Output Trial 2 |
Average Output |
0 |
1,400 |
1,150 |
1,275 |
5 |
1,300 |
900 |
1,100 |
10 |
700 |
700 |
700 |
20 |
500 |
500 |
500 |
30 |
400 |
350 |
375 |
40 |
300 |
300 |
300 |
50 |
270 |
250 |
260 |
60 |
250 |
225 |
237.5 |
70 |
200 |
200 |
200 |
Capacitor Calibrated:
Calibrating 1S2 Mic
The second part of the assignment involved selecting an input sensor of our choice and calibrating it for use.
Since I intend to use a microphone as the input sensor for my final project, I focused on calibrating an I2S microphone.
This was my first experience working with microphones and the I2S interface, setting the tone for the rest of the semester.
I hooked up the mic to an ESP32 and put a low pass filter on the sound to help filter out some of the white noise.
Furthermore, the mic was calibrated in a quiet room to a
sound at a known sound intensity (avg = 77dB).
This was compared to the absolute amplitude of the waves picked up in relation to distance away from the mic.
Distance (cm) |
Output Trial 1 |
Output Trial 2 |
Average Output |
0 |
250.30 |
195.42 |
222.86 |
1 |
305.01 |
222.71 |
263.86 |
2 |
332.43 |
229.33 |
280.88 |
3 |
264.85 |
205.75 |
235.30 |
5 |
181.54 |
142.22 |
161.88 |
10 |
87.75 |
77.55 |
82.65 |
15 |
84.63 |
56.63 |
70.63 |
20 |
68.59 |
46.90 |
57.75 |
25 |
57.14 |
41.51 |
49.33 |
30 |
52.89 |
41.43 |
47.16 |
35 |
43.92 |
41.35 |
42.64 |
40 |
34.24 |
30.39 |
32.32 |
I2S mic Calibrated: