Smart Power 3 – A $ 45 Smart Power Analysis Tool for Embedded System Developers


Hardkernel has released a number of popular SBC Arms with the ODROID family over the years, but the Intelligent power 3 is a different type of product, as the ESP32-based smart power meter can help embedded systems engineers optimize hardware and software power consumption and / or check for parasitic power peaks during start-up or shutdowns.

In the past, we’ve looked at relatively expansive tools like Qoitech Otii Arc or gone the DIY route, but at $ 45 Hardkernel offers a power monitoring solution that is both inexpensive and easy to use, albeit. with less functionality than the device from Qoitech.

Smart Power 3 specifications:

  • MCU – ESP32 Dual Core Microcontroller via ESP32-WROOM-32E Module
  • Output Channels – 2x output channels (Max 50W + 50W) via 2x banana sockets 4mm each
  • Output voltage – 3V DC to input voltage – 1V
  • Output current – 3A max per channel
  • The measure
    • Voltage, current, power
    • Maximum sampling rate: 200 Hz (5 ms interval)
  • Display – 3.5 inch TFT IPS LCD wide viewing angle, 480 × 320 resolution
  • Host interface – USB Type-C port for connection to PC for data communication and firmware upgrade
  • Various
    • Red power LED, blue “Alive” LED (active?)
    • Buttons – ON / OFF / Menu / Cancel, Output channel On / Off
    • Rotary encoder for voltage and current adjustment, also functions as selection / configuration button
  • Input voltage – 9V to 21V DC
ODROID Smart Power3 board
Internal design

Smart Power 3 AccessoriesThe device comes with a USB-C data cable and two DC plug cables (5.5 / 2.1mm) compatible with ODROID-XU4, ODROID-N2 and ODROID-C4. You’ll also need a power supply, and Hardkernel offers an optional 15V / 4A power supply that sells for $ 9.4. A 19V laptop power brick should also work, so in theory you wouldn’t necessarily need to purchase additional power.

Data is displayed in real time on the screen, but the Smart Power 3 is especially useful with its ability to send data to a host computer. Although ESP32 supports WiFi connectivity, the tool only sends data via USB to a serial interface at 921,000 bps (default). There is no sophisticated software to handle the data, and instead comma separated values ​​are sent to a serial console program like “GNU Screen”.

csv power measurementsThe data received in the terminal can then be saved to a CSV file before being imported into your preferred spreadsheet for graphing and analysis.

ODROID-N2 Raspberry Pi 4 power measurement
Power measurements with ODROID-N2 and Raspberry Pi 4

It can also be used for possible voltage drops, and the software / hardware could be optimized for applications that aim to run on battery power over time. While it is possible to watch the values ​​in real time in the serial console, the lack of real time graphics is not ideal, so maybe it could be integrated with an open source solution such as Sigrok / Pulseview or RPI-Monitor if an SBC is used on the host computer.

Implementing data acquisition over WiFi can also be of interest, both for convenience and possibly for higher sample rates (if possible depending on the rest of the hardware). The ESP32 firmware used in Smart Power 3 is open source, so it could also be improved. You can find more documentation and the source code of the firmware in the Wiki.

The Smart Power 3 tool can be purchased directly for $ 45 from the Hardkernel website and may also appear in distributors soon. Either way, the power supply isn’t optional, and at this point you need to add a 15V / 4A ($ 9.4) or 19V / 7A ($ 25) AC adapter to complete your ordered.

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