Digital inputs
Pigeon computers are equipped with 8 digital opto-isolated inputs and 4 dry contact inputs.
Digital opto-isolated inputs
The 8 digital opto-isolated inputs are divided into two sections. Refer to the diagram below.
Fig. 1. Digital opto-isolated inputs connection
The following table shows the assignment between the opto-isolated inputs and the GPIO.
Table 1. Digital opto-isolated inputs - GPIO
| INPUTS | GPIO |
|---|---|
| I1 | GPIO12 |
| I2 | GPIO13 |
| I3 | GPIO18 |
| I4 | GPIO19 |
| I5 | GPIO20 |
| I6 | GPIO21 |
| I7 | GPIO22 |
| I8 | GPIO23 |
If the input voltage is between 0 and 5V, the GPIO logic state is HIGH (negative logic). When the input voltage is in the range of 10 - 28 V, the state of GPIO is zero.
Table 2. Digital opto-isolated inputs parameters
| PARAMETER | VALUE |
|---|---|
| Quantity of inputs | 8 |
| Low-level input voltage | 0 ... +5 V DC |
| High-level input voltage | +10 ... +28V DC |
| Isolation voltage | 5 kV RMS |
| Input resistance | >=10kOhm |
Dry contact inputs
The following table shows the assignment between the dry contact inputs and the GPIO.
Table 3. Dry contact inputs - GPIO
| INPUTS | GPIO |
|---|---|
| ID1 | GPIO30 |
| ID2 | GPIO31 |
| ID3 | GPIO32 |
| ID4 | GPIO33 |
When the input is connected to GND, the logic state of the GPIO is one. Otherwise, the GPIO state is LOW.
Fig. 2. Dry contact inputs connection
Software
Bash
Read input I1 (GPIO12) state:
$ echo "12" > /sys/class/gpio/export
$ cat /sys/class/gpio/gpio12/value
$ echo "12" > /sys/class/gpio/unexport $ wget https://gitlab.com/pigeoncomputers/pigeon-rb-examples/-/raw/master/bash/read-all-binary-inputs.sh
$ chmod u+x read-all-binary-inputs.sh
$ ./read-all-binary-inputs.sh The WiringPi library is installed by default. WiringPi includes a dedicated program for managing GPIO. Read input I1 (GPIO12) state with gpio program:
$ gpio -g read 12 Python
Read input I1 (GPIO12) state:
$ python
>>> import RPi.GPIO as GPIO
>>> GPIO.setmode(GPIO.BCM)
>>> GPIO.setup(12, GPIO.IN)
>>> GPIO.input(12) 0