ET-S21
DS2484 1-Wire Hub
I²C to 1-Wire bridge for DS18B20 sensors
AED 25.00
Out of stockOverview
I²C to 1-Wire bridge for DS18B20 sensors
The ET-S21 is built around the Analog Devices/Maxim DS2484 — I2C to 1-Wire bridge, ±8kV ESD on IO, adjustable 1-Wire timing, sleep mode. It connects over I²C fixed 0x18 (up to 400kHz) and is powered from VIN 1.8–5.25V (DS2484 max 5.25V); 1-Wire supply = VIN or external via JP3.
Two Qwiic / STEMMA QT connectors let you chain it with other boards without soldering, and the 2.54 mm header fits a breadboard.
Designed in Dubai by ElectroTrical — the full schematic, BOM and design notes are published below.
Good for
- Many DS18B20 sensors on one bus
- Freezer and tank temperature chains
- Raspberry Pi 1-Wire without bit-banging
Key features
What makes it different
IC
Analog Devices/Maxim DS2484: I2C to 1-Wire bridge, ±8kV ESD on IO, adjustable 1-Wire timing, sleep mode
Interface
I2C fixed 0x18, up to 400kHz
1-Wire
Screw terminals for DQ, VCC, GND. Drives many DS18B20 probes on one bus
Supply
VIN 1.8–5.25V (DS2484 max 5.25V); 1-Wire supply = VIN or external via JP3
Qwiic / STEMMA QT
Two JST-SH connectors plus a 2.54 mm header — 3.3 V and 5 V hosts.
Open documentation
Schematic, BOM and layout notes published for every board.
Specifications
Technical specifications
| IC | Analog Devices/Maxim DS2484: I2C to 1-Wire bridge, ±8kV ESD on IO, adjustable 1-Wire timing, sleep mode |
|---|---|
| Interface | I2C fixed 0x18, up to 400kHz |
| 1-Wire | Screw terminals for DQ, VCC, GND. Drives many DS18B20 probes on one bus |
| Supply | VIN 1.8–5.25V (DS2484 max 5.25V); 1-Wire supply = VIN or external via JP3 |
| Size | 38.1 × 25.4 mm |
|---|---|
| Mounting | 4 × M2.5 holes, 2.54 mm from each corner |
| Connectors | 2 × Qwiic / STEMMA QT (JST SH 4-pin) · 4-pin 2.54 mm header · Screw terminal 2P 5.0mm 17A (THT) — 1-Wire bus: DQ / GND · Screw terminal 2P 5.0mm 17A (THT) — Sensor power: VCC / GND |
| Main IC | DS2484R+T (LCSC C124886) |
| Revision | Rev B |
| Libraries | Adafruit DS248x, ESPHome ds2484/one_wire, Linux w1 driver (DS2482 compatible command set) |
|---|
| JP1 (default Closed) | Cut to turn off the LED |
|---|---|
| JP2 (default Closed) | Cut to remove the host-side I2C pull-ups |
| JP3 (default Closed) | 1-Wire supply = VIN. Cut to feed J5 from an external supply (e.g. 5V for long cables on a 3.3V host) |
Performance
DS18B20 timing on the bus
Pinout
Pin map and connections
| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | VIN | Power | Sensor supply = host logic level |
| 2 | GND | Ground | Ground |
| 3 | SCL | I²C | I²C clock |
| 4 | SDA | I²C | I²C data |
Qwiic / STEMMA QT pins: GND, VIN, SDA, SCL (same on both connectors). I²C pull-ups (10 kΩ) are on the board; cut JP2 to remove them.
Mechanical
Dimensions and what's in the box
In the box
- 1 × ET-S21 DS2484 1-Wire Hub (assembled)
- 1 × 4-pin 2.54 mm male header, unsoldered
Getting started
- Plug in a Qwiic / STEMMA QT cable, or solder the header and wire VIN, GND, SDA and SCL
- Libraries: Adafruit DS248x, ESPHome
ds2484/one_wire, Linux w1 driver (DS2482 compatible command set) - Run an I²C scanner to confirm the address: 0x18
Compare
Which temperature probe interface?
| DS2484 1-Wire Hub (this board)This board | ET-S19 MAX31856 Thermocouple Amplifier | ET-S20 MAX31865 PT100 RTD Amplifier | ET-S16 TMP117 ±0.1 °C Temperature Sensor | |
|---|---|---|---|---|
| What it does | I²C to 1-Wire bridge for DS18B20 sensors | Universal thermocouple interface, K/J/N/R/S/T/E/B | 2/3/4-wire PT100 RTD interface | Medical-grade accuracy digital temperature sensor |
| Interface | I²C fixed 0x18, up to 400kHz | SPI (mode 1/3), up to ~1MHz through the BSS138… | SPI (mode 1/3), ≤1MHz through shifters | I²C 0x48–0x4B |
| Best for | Many DS18B20 sensors on one bus | Kilns, ovens and reflow controllers | Precise liquid temperature (brewing, sous-vide) | Precision temperature logging |
| Price | 25 AED | 59 AED | 49 AED | 39 AED |
Downloads
Documents and design files
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