I2C Temperature Sensors with FanPico

I2C Sensor Support

Starting from firmware version v1.7.0, FanPico supports some common I2C Environmental Sensors (up to 8 sensors is supported simultaneously).

I2C (temperature) sensors can be configured as "sources" to virtual sensors (VSENSORS)

Supported Sensors

Currently supported sensor types/models:

Manufacturer	Sensor Model/Type	Description	Temperature Accuracy	Humidity Accuracy	Pressure Accuracy	Notes
Analog Devices	ADT7410	16bit Temperature sensor	0.5C	N/A	N/A	Adafruit Stemma QT module tested.
ASAIR	AHT1x (AHT10, AHT11, ...)	Temperature and Humidity sensor			N/A	Generic "no name" ATH10 module tested.
ASAIR	AHT2x (AHT20, AHT21, ...)	Temperature and Humidity sensor	0.5C	3%	N/A	Generic "no name" AHT21 module tested.
AMS	AS621x series (AS6212, AS6214, AS6218)	Temperature sensor	AS6212 (0.2C), AS6214 (0.4C), AS6218 (0.8C)	N/A	N/A	Sparkfun AS6212 QWIIC module tested.
Bosch	BMP180	Digital Pressure Sensor	0.5C	N/A	0.12hPa	Generic "no name" module tested.
Bosch	BMP280	Digital Pressure Sensor	0.5C	N/A	0.12hPa	Generic "no name" module tested.
Infineon	DPS310	Barometric Pressure Sensor	0.5C	N/A	0.06hPa	Adafruit Stemma QT module tested.
Microchip	MCP9808	Digital Temperature Sensor	0.25C	N/A	N/A	Adafruit module tested.
NXP	PCT2075	Digital Temperature Sensor	1C	N/A	N/A	Generic "no name" module tested.
STMicroelectronics	STTS22H	Temperature Sensor	0.5C	N/A	N/A	Sparkfun QWIIC module tested.
Texas Instruments	TMP102	Digital Temperature Sensor	2C	N/A	N/A	Sparkfun QWIIC module tested.
Texas Instruments	TMP117	Digital Temperature Sensor	0.1C	N/A	N/A	Adafruit Stemma QT module tested.

Connecting I2C Sensors to FanPico

FanPico boards that have I2C connectors can be used with I2C Temperature sensors. (early board "0804" does not have I2C pins available, but later boards support I2C sensors).

Connecting I2C Sensors to FanPico-0401D

This board has dedicated "QWIIC" connector for easily connecting sensors from SparkFun (QWIIC) or Adafruit (Stemma QT).

Connecting I2C Sensors to FanPico-0804D

This board does not include QWIIC connector, but there is alternate pinout connector for I2C OLED module that can be used for the purpose:

Configuring I2C Temperature Sensors

I2C Temperature sensors can be configured as "source" for any of the eight virtual sensors (VSENSORS).

Enable I2C

I2C Bus must be enabled for sensors to work. FanPico-0401D has I2C bus always enabled, but FanPico-0804D I2C bus shares pins with SPI connector, so I2C is not available if SPI bus is enabled (LCD display in use, etc).

To make sure I2C is active (needed on FanPico-0804D only):

SYS:SPI OFF
CONF:SAVE
*RST

Scanning I2C Bus

After sensors have been connected, scan I2C bus to make sure sensor is seen by FanPico.

NOTE, if there is multiple sensors on same address these sensors will not work, all devices connected to I2C bus must be using unique addresses.

Scan bus after connecting a TMP117 sensor:

SYS:I2C:SCAN?
Scanning I2C Bus... 0x3c, 0x48
Device(s) found: 2

0x3c is OLED module, so TMP117 must be the second device found: 0x48

Configuring I2C Sensor as Virtual Sensor (source)

After I2C sensor is connected and successfully found using SYS:I2C:SCAN? command, it can be configured as temperature source for one of the eight virtual sensors (VSENSOR1 ... VSENSOR8).

For example, configure TMP117 sensor on address 0x48 as VSENSOR1:

CONF:VSENSOR1:SOURCE i2c,0x48,tmp117
CONF:SAVE
*RST

Check Virtual Sensor Sources

Command SYS:VSENSORS:SOURCES? can be used to list (source) configuration for all virtual sensors.

SYS:VSENSORS:SOURCES?
vsensor1,i2c,0x48,TMP117
vsensor2,manual,0.00,30
vsensor3,manual,0.00,30
vsensor4,manual,0.00,30
vsensor5,manual,0.00,30
vsensor6,manual,0.00,30
vsensor7,manual,0.00,30
vsensor8,manual,0.00,30

If logging level is set to INFO (or higher) then when FanPico boots it will log I2C sensor initialization status during boot:

SYS:LOG INFO
CONF:SAVE
[   477.066428][0] Saving configuration...
[   477.162675][0] File "fanpico.cfg" successfully created: 7401 bytes
*RST
[   481.514438][0] Initiating reboot...

[22:02:16.721] Disconnected
[22:02:17.724] Connected


FanPico-0804D v1.7.0 (Aug 23 2024; Release; SDK v1.5.1; pico_w)

Hardware Model: FANPICO-0804D
         Board: pico_w
           MCU: RP2040-B2 @ 125MHz
 Serial Number: e6614103e1234567

Found persistent memory block

[     0.986720][0] System starting...
[     0.990123][0] Uptime before soft reset: 481s
[     0.994566][0] RTC clock time: 2024-08-28 22:02:17
[     0.999383][0] Initializing I2C Bus..
[     1.003155][0] I2C Bus initialized at 1000 kHz
[     1.010508][0] I2C Device TMP117 (at 0x48): mapped to vsensor1
[     1.013934][0] Initializing OLED Display...
[     1.068544][0] I2C OLED Display: SH1107 (at 3c)
[     1.101574][0] Initializing WiFi...
[     1.102487][0] WiFi country code: 005355 (US)
...
[     5.981634][1] vsensor1: Temperature change 0.0C --> 24.8C
...