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| Homemade sensors can be connected to the inputs of the PIC microcontroller circuit. The drawing below shows a homemade temperature sensor being used, as an input to the microcontroller circuit. It has been connected to INPUT A/D 0. When the genie microcontroller circuit is programmed, the sensor becomes a type of switch. The temperature sensor can be used to trigger OUTPUTs, such as LEDs or motors. | |
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| Homemade temperature sensors
normally have three wires, that connect to the INPUTS on the
microcontroller circuit. Opposite. is a simple temperature sensor. The most important component is the thermistor (click here for more information on thermistors). This temperature circuit, can be connected as an input to a microcontroller circuit. The temperature sensing circuit has three green wires (1, 2 and 3). Wire 2 should always be connected to one set of the inputs. If wire 1 is also connected then the sensor energises the relay, as the temperature rises . If wires 2 and 3 are connected to the inputs, then sensor energises the relay, as the temperature falls. |
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| Click here for more information on typical temperature sensors | |
| The diagram below, shows the temperature sensor, connected to the GENIE E18 PIC Microcontroller’s inputs. This microcontroller has five inputs and the sensor is connected to A/D 0, although it could be connected to any input. | |
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| SIMPLE PRACTICAL APPLICATIONS: | |
| It is quite
easy to program the GENIE E18 PIC microcontroller, to work in the
following way: When the relay of a temperature sensor, connected to an input, de-energises, the microcontroller turns on a warning LED. The LED remains on until the temperature rises, energising the relay again. |
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| This could have a simple but effective practical application. If the PIC microcontroller and temperature sensor is placed on the outside of a car, when the temperature decreases too far, a warning light illuminates. This warns the driver of the possibility of ice. | |
| Alternatively: If the sensor and PIC microcontroller is placed in a baby’s bedroom, when the temperature rises too high, a air conditioning unit could automatically turn on, cooling down the room to a safe temperature. | |
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