ET-S38
2-Channel CT Clamp Interface
SCT-013 clamp interface with 16-bit I²C ADC
AED 49.00
Out of stockOverview
SCT-013 clamp interface with 16-bit I²C ADC
The ET-S38 is built around the Non-invasive AC current monitoring with 2 clip-on CTs (YHDC SCT-013-000 100A:50mA or voltage-output types). It connects over I²C 0x48 and is powered from VIN 3.3–5.5V (5V gives more headroom).
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
- Home energy monitoring
- Appliance power logging
- Solar and grid metering
Key features
What makes it different
Function
Non-invasive AC current monitoring with 2 clip-on CTs (YHDC SCT-013-000 100A:50mA or voltage-output types)
ADC
TI ADS1115, differential AIN0−AIN1 / AIN2−AIN3 around a VIN/2 bias, 860 SPS
Range
SCT-013-000 + 22Ω: ±1.56V peak at 100A rms (PGA ±2.048V). Resolution ~10mA
Interface
I2C 0x48
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
| Function | Non-invasive AC current monitoring with 2 clip-on CTs (YHDC SCT-013-000 100A:50mA or voltage-output types) |
|---|---|
| ADC | TI ADS1115, differential AIN0−AIN1 / AIN2−AIN3 around a VIN/2 bias, 860 SPS |
| Range | SCT-013-000 + 22Ω: ±1.56V peak at 100A rms (PGA ±2.048V). Resolution ~10mA |
| Interface | I2C 0x48 |
| Supply | VIN 3.3–5.5V (5V gives more headroom) |
| Safety | CTs clip around insulated wires; nothing on this board touches mains |
| 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) · 5-pin 2.54 mm header |
| Main IC | ADS1115IDGSR (LCSC C37593) |
| Revision | Rev B |
| Libraries | EmonLib-style RMS sketch on ADS1115 (provide example), ESPHome ads1115 + ct_clamp |
|---|
| JP1 (default Closed) | Cut to turn off the LED |
|---|---|
| JP2 (default Closed) | Cut to remove the host-side I2C pull-ups |
| JP3 (default Closed) | CT1 burden. Cut for voltage-output CTs (SCT-013-030/050 etc.) |
| JP4 (default Closed) | CT2 burden. Cut for voltage-output CTs |
Performance
Signal vs load
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 |
| 5 | ALERT | Output | ADS1115 ALERT/RDY, open-drain |
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-S38 2-Channel CT Clamp Interface (assembled)
- 1 × 5-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: EmonLib-style RMS sketch on ADS1115 (provide example), ESPHome
ads1115+ct_clamp - Run an I²C scanner to confirm the address: 0x48
Compare
Which current and power board?
| 2-Channel CT Clamp Interface (this board)This board | ET-S07 INA228 85 V Power Monitor | ET-S37 ACS725 ±20 A Current Sensor | ET-S39 ATM90E32 3-Phase Energy Monitor | |
|---|---|---|---|---|
| What it does | SCT-013 clamp interface with 16-bit I²C ADC | 20-bit current, voltage, power and energy monitor | Isolated Hall current sensor with 16-bit I²C ADC | 3-phase energy metering IC with CT inputs |
| Interface | I²C 0x48 | I²C 0x40 default; 0x41/0x44/0x45 via JP3/JP4 (16… | I²C 0x48; raw analog VIOUT also on J3.6 | SPI (mode 3) on J3. No Qwiic (SPI part) |
| Best for | Home energy monitoring | Battery and solar monitoring | Motor current monitoring | 3-phase energy metering |
| Price | 49 AED | 59 AED | 49 AED | 219 AED |
Downloads
Documents and design files
Need a custom version of this board?
Different connector, size or sensor? We design and build custom variants.