4/1/2023 0 Comments Simple divider design![]() Many of those sensors operate at a relatively low voltage, in order to conserve power. More complicated sensors may transmit their readings using heavier serial interfaces, like a UART, SPI, or I2C. Plenty of resolution for most ADCs! Level Shifting Light LevelĪ swing of about 2.45V from light to dark. The voltage is measured to find the resistance of the light sensor. Photocell makes up half of this voltage divider. If we combine that with a static resistance somewhere in the middle - say 5.6kΩ, we can get a wide range out of the voltage divider they create. Once the output of the voltage divider is known, we can go back and calculate the resistance of the sensor.įor example, the photocell's resistance varies between 1kΩ in the light and about 10kΩ in the dark. But, by adding another resistor to the resistive sensors, we can create a voltage divider. It turns out voltage is really easy for microcontrollers (those with analog-to-digital converters - ADC’s - at least) to measure. Other devices like flex sensors, force-sensitive resistors, and thermistors, are also variable resistors. A photocell is a variable resistor, which produces a resistance proportional to the amount of light it senses. ![]() Many sensors in the real world are simple resistive devices. They may be used to create a reference voltage, adjust radio stations, measure position on a joystick, or in tons of other applications which require a variable input voltage. Potentiometers come in a variety of packages, and have many applications of their own. Turn the pot all the way in one direction, and the voltage may be zero turned to the other side the output voltage approaches the input a wiper in the middle position means the output voltage will be half of the input. If the outside pins connect to a voltage source (one to ground, the other to V in), the output (V out at the middle pin will mimic a voltage divider. ![]()
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