Pisensors

PiSensors is a C source library for reading DHT11 and DHT22 (AM2302)
temperature and humidity sensors on the Raspberry Pi GPIO header under
piAROS (Raspberry Pi 3 / 3B+ / 4).

It is a source / link library, not a system .library: there is nothing
to install. Add the source files to your project, or link the included
libpisensors.a, and read a sensor with a few lines of C:

    pig_open();
    if (pidht_read(4, 0, &r) == PIG_OK)
        printf("%s Cn", pig_tenths_to_str(buf, r.temp10));

DHT11 / DHT22 driver (pidht):
 - automatic sensor type detection
 - temperature and humidity as integers in tenths (215 = 21.5 C),
   no floating point needed
 - 2-second guard: the sensor is never read too often
 - clear error codes; on a timeout it tells where the reading stopped
   (no pull-up, no response, data cut off ...)
 - raw data bytes for diagnosis
 - the data pin is only ever driven low, never high, and left as input

GPIO layer (pigpio), usable for your own drivers:
 - read and set pins with safety checks: only GPIO 2..27 can be
   changed, pins used by UART / I2C / SPI are refused unless you pass
   PIG_FORCE
 - microsecond timer that also works with interrupts disabled
 - board detection; Raspberry Pi 5 is refused (GPIO is in the RP1 chip)

Included:
 - pigpio.c/h, pidht.c/h      the library
 - libpisensors.a             ready-built link library
 - example_dht.c, DHTRead     example program for the Shell
 - build.sh                   build script for the AROS cross compiler
 - manual.txt                 API reference, wiring, troubleshooting
 - license.txt                MIT licence

Planned: DS18B20 (1-Wire), BME280 / BMP280 (I2C).

Connecting sensors is done at your own risk. Read the safety chapter in
manual.txt before wiring anything. GPIO pins are 3.3 V only - never
connect 5 V to a GPIO pin.

Copyright (c) 2026 rhun. MIT licence. Provided "as is", without
warranty of any kind.