1‐Wire Temperature Sensors with FanPico
Starting from firmware version v1.7.0, FanPico supports some common 1-Wire Temperature Sensors (up to 8 sensors is supported simultaneously).
1-Wire Temperature sensors can be configured as "sources" to virtual sensors (VSENSORS)
Currently supported sensor models:
| Device | Type | Notes |
|---|---|---|
| DS18S20 | Temperature sensor (9bit) | |
| DS1822 | Temperature sensor (9-12bit) | |
| DS18B20 / MAX31820 | Temperature sensor (9-12bit) | |
| DS1825 / MAX3826 | Temperature sensor (9-12bit) | |
| DS28EA00 | Temperature sensor (9-12bit) |
FanPico boards that have dedicated "1-Wire" connector or "LCD (SPI)" connector support 1-Wire sensors.
Early boards don't dedicated connector (or built-in pull-up resistor) but can be used with appropriate cable/adapter.
This board has dedicated "1-Wire" connector for easily connecting sensors.
NOTE! Jumper (JP12) next to 1-Wire connector is used to enable built-in 4.7K pull-up resistor. This jumper should normally be installed (unless there is need to use external pull-up resistor).
This board does not have dedicated 1-Wire connector, but 1-Wire sensors can be connected via pins on the "LCD (SPI)" connector.
| Pin Label | 1-Wire | Notes |
|---|---|---|
| DC | DQ (Data) | |
| Vcc | Vdd | |
| GND | GND | |
| RST or BL | (Pull-Up) | 1-Wire needs pull-up (4.7k) resistor between DQ and Vdd these pins can be used to 3.3V for the pull-up resistor. |
1-Wire sensor connected via "LCD (SPI)" connector using adapter cable:
Adapter cable (with built-in 4.7K resistor) for connecting 1-Wire sensors:
To use 1-Wire temperature sensors, support for 1-Wire must be enabled: SYS:ONEWIRE ON
To use 1-Wire, support must be enabled:
SYS:ONEWIRE ON
CONF:SAVE
*RST
To use 1-Wire, SPI and Serial must be disabled in the configuration:
SYS:SERIAL OFF
SYS:SPI OFF
SYS:ONEWIRE ON
CONF:SAVE
*RST
After 1-Wire support has been enabled and unit rebooted, detected 1-Wire sensors can be viewed
usign command SYS:ONEWIRE:SENSORS?
For example:
SYS:ONEWIRE:SENSORS?
1,280dd46900000016,24.1
After 1-Wire sensor is connected and successfully found using SYS:ONEWIRE:SCAN? command, it can be configured
as temperature source for one of the eight virtual sensors (VSENSOR1 ... VSENSOR8).
For example, configure sensor on address 280dd46900000016 as VSENSOR2:
CONF:VSENSOR1:SOURCE onewire,280dd46900000016
CONF:SAVE
*RST
Command SYS:VSENSORS:SOURCES? can be used to list (source) configuration for all virtual sensors.
SYS:VSENSORS:SOURCES?
vsensor1,i2c,0x48,TMP117
vsensor2,onewire,280dd46900000016
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 1-Wire 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...
[23:14:54.455] Disconnected
[23:14:55.457] 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
[ 0.971136][0] System starting...
[ 0.971370][0] Uptime before soft reset: 1467s
[ 0.971576][0] RTC clock time: 2024-08-29 23:14:55
[ 0.971675][0] Initializing I2C Bus..
[ 0.971807][0] I2C Bus initialized at 1000 kHz
[ 0.974914][0] I2C Device TMP117 (at 0x48): mapped to vsensor1
[ 0.975341][0] Initializing OLED Display...
[ 1.026020][0] I2C OLED Display: SH1107 (at 3c)
[ 1.057364][0] Initializing WiFi...
[ 1.057581][0] WiFi country code: 005355 (US)
...
[ 1.873551][0] Initializing 1-Wire Bus...
[ 1.875872][0] Scanning 1-Wire bus...
[ 1.879131][0] All devices in 1-Wire bus have power.
[ 1.894435][0] 1-Wire device count change detected: 0 --> 1
[ 1.894712][0] 1-Wire Device1: 280dd46900000016
[ 1.894838][0] System initialization complete.
...