Table of Contents
Sensor module
Sensor module includes Sensor board with on-board sensors, low-pass filter and external sensors.
Sensor module features
- Electret microphone
- Light intensity sensor (photoresistor) VT935G (resistance 18,5 kΩ on 10 lux) datasheet
- Temperature sensor (thermistor NTC) (resistance 10 kΩ on 25 °C) datasheet
- Potentiometer 10 kΩ
- Ultrasonic distance measure sensor Devantech SRF05 with cable (measuring distance 1-400 cm) datasheet
- Infrared distance sensor Sharp GP2Y0A21YK0F (measuring distance 10-80 cm) datasheet
Electrical connections
On-board sensors are connected as follows:
| on-board notation | external notation | on-board sensor | microcontroller port |
|---|---|---|---|
| MIC | AD0 | Microphone | PF0 |
| LDR | AD1 | Light intensity sensor | PF1 |
| NTC | AD2 | Temperature sensor | PF2 |
| POT | AD3 | Potentiometer | PF3 |
Sensors
Every sensor on the board is connected through the multiplexer, enabling to select between on-board sensor or external sensor which can be connected to the same port through the connectors. By default all on-board sensors are connected to the analogous inputs of the microcontroller (ADC0-ADC3). Multiplexer is controlled with the port PG0.
Schematics of multiplexer
Schematics of sensor connections
Low-pass filter
Low-pass filter can be composed between external analogous inputs 0-3 (PF0-PF3). Resistor and capacitor will be connected to the socket for building up the low-pass filter. By default a low-pass filter is not composed only 1 Ohm resistors are included for all channels.
Schematics of external sensor connections and low-pass filter
Digital I/O connector
In addition to sensors and analog inputs, there is a connector for digital I/O. Digital I/O pins are directly connected to pins PE2-PE5 of the controller. Also digital serial interface connector is in use (74HCT165D), which is convenient for connecting similar digital sensors. Digital serial interface is connected as following: clock input - PC7, asynchronous parallel load input (active LOW) - PA6, serial output from the last stage - PA7.
The digital input/output connectors
