School of Maaa Day 2 - Voltage Dividers

Theory behind making your own variable resistor sensors.

Transcript

1. Voltage Dividers
2. Pressure Sensor Cushion Pauline Vierne http://etextile-summercamp.org/2014/pressure-sensor-cushion/
3. LaceSensor Dresses Anja Hertenberger and Meg Grant http://lacesensorproject.com/
4. Mi.Mu Gloves http://theglovesproject.com/
5. Stretch Sensor
6. Soft Potentiometers
7. Squeeze Sensor
8. Arduinos can only watch changes in voltage. ! Not changes in resistance or current.
9. But we can turn a changing current or resistance into a changing voltage by being clever.
10. Vin Vout GND GND R1 R2 Voltage Divider
11. Vin Vout 5V GND GND R1 R2 Something between 5V and GND Voltage Divider
12. Vin Vout 5V GND GND R1 R2 Something between 5V and GND Voltage Divider
13. Vin Vout 5V GND GND R1 R2 Something between 5V and GND Voltage Divider = Vout Vin x R1 + R2 R2
14. Vin Vout GND GND R2 Voltage Divider R1 knit sensor
15. Vin Vout GND GND R2 Voltage Divider R1 knit sensor
16. Voltage Divider
17. Vin Vout GND R1 R2 Voltage Divider potentiometer *In this circuit, both R1 and R2 are changing when the knob is turned.
18. Voltage Divider 1. Does the object change resistance when you interact with it? Check with a multimeter. 2. If does, create a voltage divider. Decide if you want the object to be R1 or R2. 3. Choose a static resistor that gives you the values you are looking for.
19. Challenge Create an analog sensor using soft materials. Demonstrate it working with an Arduino.