Sensor module v5.2

(Version 5.2)

Sensor module includes the combined board of 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

On-board sensors are connected as follows:

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 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 composed for the channel 0 (PF0). Resistor value is 10 kΩ and capacitor value is 100 nF.

Schematics of external sensor connections and low-pass filter

In addition to sensors and analog inputs, there is a connector for digital I/O on the board. The pins of the connector are directly connected to pins PE2-PE5 of the controller. Also digital serial interface connector is in use (74HCT165D), which is convenient if similar sensors are used. 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