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tutorials:learn:sensors:fsr.html [2010/10/07 19:30] daigo |
tutorials:learn:sensors:fsr.html [2010/10/07 19:31] daigo |
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^Force (lb)^Force (N)^FSR Resistance^(FSR + R) Ω^Current thru FSR+R^Voltage across R^ | ^Force (lb)^Force (N)^FSR Resistance^(FSR + R) Ω^Current thru FSR+R^Voltage across R^ | ||
- | ^None^None^|Infinite|Infinite!|0 mA|0V| | + | ^None^None|Infinite|Infinite!|0 mA|0V| |
- | ^0.04 lb^0.2 N^|30KΩ|40 KΩ|0.13 mA|1.3 V| | + | ^0.04 lb^0.2 N|30KΩ|40 KΩ|0.13 mA|1.3 V| |
- | ^0.22 lb^1 N^|6 KΩ| 16 KΩ|0.31 mA|3.1 V| | + | ^0.22 lb^1 N|6 KΩ| 16 KΩ|0.31 mA|3.1 V| |
- | ^2.2 lb^10 N^|1 KΩ|11 KΩ|0.45 mA|4.5 V| | + | ^2.2 lb^10 N|1 KΩ|11 KΩ|0.45 mA|4.5 V| |
- | ^22 lb^100 N^|250 Ω|10.25 KΩ|0.49 mA|4.9 V| | + | ^22 lb^100 N|250 Ω|10.25 KΩ|0.49 mA|4.9 V| |
//This table indicates the approximate analog voltage based on the sensor force/resistance w/a 5V supply and 10K pulldown resistor// | //This table indicates the approximate analog voltage based on the sensor force/resistance w/a 5V supply and 10K pulldown resistor// | ||
Note that our method takes the somewhat linear resistivity but does not provide linear voltage! That's because the voltage equasion is: | Note that our method takes the somewhat linear resistivity but does not provide linear voltage! That's because the voltage equasion is: | ||
- | <p align="center" class="style2">Vo = Vcc ( R / (R + FSR) ) | + | <code>Vo = Vcc ( R / (R + FSR) )</code> |
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That is, the voltage is proportional to the **inverse** of the FSR resistance. | That is, the voltage is proportional to the **inverse** of the FSR resistance. |