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1-Wire® to I2C

Connect I2C sensors to the 1-Wire® to I2C adapter.


1-Wire<sup>®</sup> to I2C

Feature List

  • Connect multiple I2C buses to your 1-Wire® bus on the IO Expander.
  • I2C bus only at the end so it solves the limited cable length of I2C.
  • Use multiple 1-Wire® to I2C adapters to connect multiple I2C sensors with the same I2C address.
  • I2C bus is 3V3 250mA.
  • 4.7kΩ I2C bus pull-ups on R3 and R4.
  • PL1 jumper to select D1 or D2.
  • Software selectable I2C bus speeds of 100kHz or 400kHz.
  • 1-Wire® Standard or Overdrive(default) speed.
  • Low power 2.6mA typical.
  • 34.4mm x 15mm.

RJ11 Ports
Pin Function
1 NC
2 5V
3 D1
4 Gnd
5 D2
6 NC

The following I2C sensors are supported by the IO Expander.


# Sensor Type
2 HTU2x,SHT2x Temperature/Humidity
3 SHT3x Temperature/Humidity
8 Si702x Temperature/Humidity
9 TSL2561 Light
a TL2561CS Light
b BMP180 Temperature/Pressure
c LM75 Temperature
e DS3231 RTC/Temperature
f AT24C32 Serial EEPROM
10 SSD1306/SSD1309 OLED Display
11 MCP9600 Thermocouple Temperature
12 HX711 Load Cell Weight
13 SH1106 OLED Display
14 TSL2591 Light
15 TCS34725 RGB Light
16 SCD30 CO2 Temperature/Humidity
18 BMP280 Temperature/Pressure
19 BME280 Temperature/Humidity/Pressure
1a PCF8574 8-bit Expander
1b ADS1015 12-bit 4-Channel ADC Expander
1c SCD40,SCD41 CO2 Temperature/Humidity

Using the IO Expander you can communicate with the I2C device directly using the 'i' cmd or connect many of the supported I2C sensors using the 's' cmd.


subcmd Function Mode
a[address] Ascii Read[address] (New v1.15) Hex
c[speed] Config[0-100kHz,1-400kHz]
f Find only DS28E17
n Scan Addresses
o[n] Speed[0-Standard,1-Overdrive] (New v1.15)
r(address)[read[write]] Read(address)[# bytes to read[write bytes]] Hex
s Select[64-bit ID] Hex
w(address)(write) Write(address)(write bytes) Hex
? Device Revision

1-Wire is a registered trademark of Maxim Integrated Products, Inc.