Testing the robomouse to see how it’s running. It runs slowly so I modified the delay in the program to see the difference. After a few tests the battery becomes flat and need to be recharged. Therefore I proceed on sensor testing in order to determine the relationship between the output voltage and distance. I’m using a distance measuring sensor with analog output model Sharp GP2Y0A41SK0F. The distance measuring range is 4 cm to 30 cm. The sensor has 3 pins as below:
Pin No. | Signal Name |
1 | Vo |
2 | GND |
3 | Vcc |
Initially, the output voltage reading is not stable. According to the datasheet, a by-pass capacitor of 10 uF or more has to be connected between Vcc and GND near this product in order to stabilize the power supply line. So, a by-pass capacitor of 10 uF is connected and the output voltage becomes stable. The output voltages for distance measurement from 2 cm to 40 cm were recorded and plotted into graph. The results are as below:
Distance (cm) | Output voltage (V) |
2 | 2.43 |
4 | 2.63 |
6 | 1.89 |
8 | 1.46 |
10 | 1.21 |
12 | 1.02 |
14 | 0.88 |
16 | 0.76 |
18 | 0.67 |
20 | 0.56 |
22 | 0.47 |
24 | 0.39 |
26 | 0.31 |
28 | 0.27 |
30 | 0.22 |
32 | 0.19 |
34 | 0.15 |
36 | 0.13 |
38 | 0.11 |
40 | 0.10 |
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| The sensor |
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| Sensor circuit with 10 uF capacitor |
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| Measurement process (white box as the object / wall) |
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| Distance 2 cm |
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| Distance 6 cm |
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| Distance 10 cm |
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| Distance 20 cm |
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| Distance 30 cm |
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| Distance 40 cm |
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