rbAmp modules — read AC energy over I²C, in physical units.

Read RMS voltage, current, signed power, PF and tariff energy over a 2-wire I²C bus — physical units, no master-side DSP. Up to 128 modules on one 2-wire bus. Bring your own controller — ESP32, Raspberry Pi or PLC.

ESPHome Arduino Python (Raspberry Pi) ESP-IDF

Choose a model ↓ Docs & libraries

Why rbAmp modules

One UART is never enough — go I²C

Most MCUs have a single UART, usually taken by the debug console; Arduino SoftwareSerial is flaky. rbAmp talks I²C: many modules on two shared pins, and your UART stays free.

Physical units — zero master-side math

The module does ADC/DSP/true-RMS at 5 kHz and returns ready float32 U/I/P/PF — not raw samples. No interrupts, no sine-catching, no DSP code on your MCU.

Atomic Wh latch → tariff-correct energy

One CMD_LATCH_PERIOD closes/opens a period with no read-reset gap; no dropped or double-counted samples. Energy computed master-side, matches utility intervals.

Open API + open libraries

Documented register/command map + native MIT libs (ESPHome / Arduino / ESP-IDF / Python). Any stack, or your own code.

Galvanically isolated — safe by design

Mains-side (HV) and signal-side (LV) are fully isolated: isolated voltage front-end + toroidal CT + isolated I²C. Safe for you and for your controller.

3.3 V logic, 5 V-tolerant — no level shifter

SDA/SCL/DataReady connect straight to ESP32 or Raspberry Pi GPIO. Power VCC at 5 V; on-board 3.3 V regulator handles the rest.

Choose your module in 2 steps

Step 1 — What do you measure?

Voltage + current → Wattmeter (UI series)

Full U / I / P / PF / Wh. Connects to 110/230 VAC (line + neutral) to power the measuring core.

Current only → Ammeter (I / A series)

I_rms per channel. Ideal to add channels when voltage is already measured by another module on the bus.

Step 2 — How will you mount the current sensor?

CT-wired (through-core)

Sensor accuracy 0.3–1%, plug-in screw terminals, sees loads from 50 W. One-time power-down at install.

SCT-013 (clamp)

Clip-on, no power-down, 3.5 mm jack, sensor accuracy 1–3%.

Total accuracy = module (~0.5%) + sensor. Pick a tighter sensor for tighter results. Module + matching CT available as a bundle (coming).

Available now — BASIC line

Bare-PCB modules (embed in your own enclosure; no DIN housing in Basic). Buy the module alone, or the module + matching sensor as a bundle.

CT-wired — precision, through-core

CT-wired Wattmeter — UI1 / UI2

Precision wattmeter for panels.

U+I+P+PF+freq+Wh · module ~0.5% + sensor 0.3–1% · loads from 50 W.

Module Module + Sensor

CT-wired Ammeter — A1 / A2 / A3

Multi-channel precision ammeter.

I_rms / I_peak per channel · module ~0.5% + sensor 0.3–1%.

Module Module + Sensor

SCT-013 — clamp-on

SCT-013 Wattmeter — UI1 / UI2 / UI3

Flexible wattmeter for non-invasive retrofit (1–3 ch).

U+I+P+PF+freq+Wh · clip-on, no power-down · module ~0.5% + sensor 1–3%.

Module Module + Sensor

SCT-013 Ammeter — I1 / I2 / I3

Add cheap current channels to your bus.

I_rms / I_peak per channel · module ~0.5% + sensor 1–3%.

Module Module + Sensor

From wire to data in 3 steps

Ready open libraries for every platform — from wire to data in minutes.

Connect

Wire the module: 2-wire I²C to your controller + the current sensor.

Upload

Drop in the open library — a few lines (ESPHome / Arduino / ESP-IDF / Python).

Result

Read ready physical units: U / I / P / PF / Wh in your dashboard.

Browse all libraries →

Ready to move your energy monitoring to I²C? Start now.

Begin with the BASIC line — available today. Full docs and open libraries included.

Browse the Basic line Read the docs

rbAmp platform — development vector

The rbAmp measurement core is unified — I²C is the base today.

Standard line

In development

Headline edge: bidirectional (live signed power, export counted) + 8 independent atomic-period accumulators (per-channel tariff energy in one latch).

● Module accuracy ~0.3% (vs Basic ~0.5%)
● Noise floor <10 mA (standby-load tracking)
● Up to 8 current channels per module
● Per-channel phase compensation

● Diagnostic flags (CT_DISCONNECTED, SATURATION, U_OUT_OF_RANGE)
● Traceable factory calibration

Watch on GitHub

PRO line

Roadmap

Power-quality analyzer: THD / harmonics, sag-swell events, 4-quadrant signed energy, 3-phase, waveform capture.

Interfaces

Roadmap

RS-485 / Modbus and Wireless (ESP-NOW / BLE) arrive in later revisions, with the same integration logic — no change to your master-side code.

Tier	I²C	Wireless (ESP-NOW / BLE)	Modbus RS-485
Basic	✅ Available	— Roadmap	— Roadmap
Standard	◐ In development	— Roadmap	— Roadmap
PRO	— Roadmap	— Roadmap	— Roadmap

✅ available · ◐ in development · — roadmap

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