Crate pamoja_sensors

Expand description

Concrete sensor drivers for the pamoja SDK.

pamoja-gpio builds the address and mode bytes a controller puts on an I2C or SPI bus; this crate is the layer just above it, the per-part knowledge that turns the raw register bytes a specific sensor returns into a physical reading. Each module is one named part: it knows that part’s register map, builds the bytes that configure it, and decodes what it sends back, applying the exact conversion the manufacturer’s datasheet specifies.

Each module is two layers. The decode layer is pure logic with no I/O: the register map, the bytes that configure the part, and the conversion of what it sends back, so it runs on a microcontroller, on a gateway, and in a test with nothing plugged in. The driver layer (the embedded-hal feature, on by default) is a type named after the part that owns a bus from pamoja-hal, performs the datasheet’s transfer sequence, and implements the core Sensor trait, so a Bme280 reads through any embedded-hal I2C or SPI implementation and a Ds18b20 through any 1-Wire bus. A driver’s reading is the part’s full measurement; Sensor::map selects one channel for a controller that wants a single number. Every driver is tested against its datasheet’s own transfer sequence over a scripted bus, and a driver’s error converts into the core error so the part slots into a profile or a node unchanged. The shapes the drivers share, a register bus over I2C or SPI and the 16-bit register access of the Texas Instruments parts, are in driver.

The conversions are anchored to each datasheet’s own reference values, since they are where memory-driven bugs hide. The BME280 compensation is ported from Bosch’s published reference code and cross-checked against its floating-point form; the DS18B20 decode is pinned to the datasheet’s temperature/data table and its CRC to the Maxim 1-Wire polynomial; the INA219 math is checked against the datasheet’s worked design example; the ADS1115 full-scale conversion against its per-gain LSB sizes. The parts added after those follow the same rule: the BMP280 port of Bosch’s integer compensation against its floating-point form; the SHT3x and SCD4x conversions against the endpoints of their linear formulas, their command words against the tables, and their CRC-8 against Sensirion’s published check value; the TMP117 decode against its temperature data table; the HDC1080 equations against their endpoints and identification registers; the OPT3001 lux decode against its table of worked result words and its full-scale table; the INA226 math against the datasheet’s calibration example.

bme280 - Bosch temperature, pressure, and humidity over I2C or SPI.
bmp280 - Bosch pressure and temperature, the BME280 without humidity.
ds18b20 - Maxim 1-Wire digital thermometer, with CRC-checked scratchpads.
hdc1080 - Texas Instruments low-power I2C humidity and temperature sensor.
ina219 - Texas Instruments high-side current, voltage, and power monitor.
ina226 - Texas Instruments high- or low-side current, voltage, and power monitor with an alert pin.
ads1115 - Texas Instruments 16-bit I2C analog-to-digital converter.
opt3001 - Texas Instruments ambient light sensor with a human-eye response.
scd4x - Sensirion SCD40 and SCD41 photoacoustic CO2 sensors with humidity and temperature, over I2C.
sht3x - Sensirion humidity and temperature sensor, with CRC-checked words.
tmp117 - Texas Instruments ±0.1 °C digital temperature sensor with alert limits.

§Examples

A greenhouse soil bed, read through a TMP117 that is not plugged in yet, as the one number a controller wants: Sensor::map picks degrees Celsius out of the part’s full reading. A real bus from pamoja-hal takes the simulated part’s place unchanged.

use pamoja_core::Sensor;
use pamoja_hal::script::{block_on, DelayLog};
use pamoja_sensors::tmp117::{address, sim, Tmp117};

let part = sim::reporting(address::ADD0_GND, 18.5);
let thermometer = Tmp117::new(part, address::ADD0_GND, DelayLog::new());
let mut celsius = thermometer.map(|reading| reading.celsius());
assert_eq!(block_on(celsius.read())?, 18.5);

Modules§

ads1115: Texas Instruments ADS1115 16-bit I2C analog-to-digital converter.
bme280: Bosch BME280 temperature, pressure, and humidity sensor.
bmp280: Bosch BMP280 digital pressure sensor.
driver: What the drivers share: how a register-mapped part is reached over a bus.
ds18b20: Maxim DS18B20 1-Wire digital thermometer.
hdc1080: Texas Instruments HDC1080 low-power humidity and temperature sensor.
ina219: Texas Instruments INA219 high-side current, voltage, and power monitor.
ina226: Texas Instruments INA226 high-side or low-side current, voltage, and power monitor.
opt3001: Texas Instruments OPT3001 ambient light sensor.
scd4x: Sensirion SCD40 and SCD41 CO2, temperature, and humidity sensor.
sht3x: Sensirion SHT3x-DIS humidity and temperature sensor (SHT30, SHT31, SHT35).
tmp117: Texas Instruments TMP117 high-accuracy digital temperature sensor.

Enums§

DriverError: What can go wrong driving a part over a bus, beyond decoding its bytes.
SensorError: What can go wrong turning a part’s raw bytes into a reading.