Edge AI Power 3: Measuring Edge AI Power with INA228

Hailo and ElmorLabs power measurement solutions were replicated using a custom INA228 circuit from Adafruit components, enabling edge AI power benchmarking. The setup combines an FT232H USB-to-I2C board, INA228 power monitor, and ElmorLabs PCIe adapter to measure the 3.3V rail. Open-source tool mb-powermon.py now supports these components for reproducible testing.

In the first article, we gave an overview of Hailo’s power measurement solution. In the second article, we attempted to reproduce these power measurements with the ElmorLabs solution. Series : Edge AI Power Benchmarking Part 1: Hailo-8, the Reference Methodology https://mariobergeron.com/posts/edge-ai-power-p01-hailo8/ Part 2: Power Insertion with ElmorLabs https://mariobergeron.com/posts/edge-ai-power-p02-elmorlabs/ - Part 3: Measuring Edge AI Power with INA228 this post Part 4: Measuring the Power Efficiency of Axelera Metis https://mariobergeron.com/posts/edge-ai-power-p04-axelera-metis/ Part 5: Measuring the Power Efficiency of DeepX M1 https://mariobergeron.com/posts/edge-ai-power-p05-deepx-m1/ Part 6: Measuring the Power Efficiency of MemryX MX3 https://mariobergeron.com/posts/edge-ai-power-p06-memryx-mx3 In this article, we repeat the same experiment, this time by prototyping a custom INA circuit with available components from Adafruit. Essential Components from AdafruitAfter further investigation, I discovered that Adafruit has several flavors of INA circuit boards, in addition to a USB to I2C board. These components interoperate together to offer a working power measurement solution out of the box. Adafruit FT232H Breakout - General Purpose USB to I2C https://www.adafruit.com/product/2264 - $15 USD Adafruit INA228 I2C Power Monitor https://learn.adafruit.com/adafruit-ina228-i2c-power-monitor - $14 USD STEMMA QT / Qwiic JST SH 4-pin Cable https://www.adafruit.com/product/4210 - $1 USD We will be combining this with the ElmorLabs PCIe power insertion adapter, which exposes the 3V3 rail as a jumper, which we can easily tap into. Assembling the SystemThis solution was significantly easier to set up. The FT232H breakout had a single switch to set for use with I2C: - I2C Mode : set to ON Regarding the INA228 module, contrary to what I was expecting, no soldering was required to configure the board. The FT232H breakout and INA228 module were connected with a STEMMA QT cable. I adapted a 2 wire power cable I had, and exposed one of the ends to connect up to the INA228 module. I also wired the +V terminal to the Vbus, for use in High-Side mode i.e. measuring the 3.3V rail, instead of ground My custom cable was inserted on the jumper site of the 3V3 rail on the ElmorLabs PMD power insertion adapter. In order to get positive readings, the important connections to make are: - V+ connected to 3V3 red cable - FROM SLOT pin - V- connected to 3V3 black cable - TO CARD pin In order to perform our testing, I have added support for the Adafruit FT232H and INA228 components in my mb-powermon.py utility The first step is to clone the repo for my open-source power monitoring utility. bash hailo virtualenv $ git clone https://github.com/AlbertaBeef/mb-powermon hailo virtualenv $ cd mb-powermon Within the hailo docker container, install the “pyftdi”, “adafruit-blinka”, and “adafruit-circuitpython-ina228” python packages. bash hailo virtualenv $ pip3 install pyftdi adafruit-blinka adafruit-circuitpython-ina228 Make certain you have permission to access the enumerated FTDI USB device. I have included a script that can be run outside the docker container called fix-ft232h-permissions.sh use with caution : $ ./fix-ft232h-permissions.sh ft232h-fix scanning /sys/bus/usb/devices for VID:PID 0403:6014... ft232h-fix found FT232H at sysfs path /sys/bus/usb/devices/9-1/ bus=9 dev=2 ft232h-fix device node: /dev/bus/usb/009/002 ft232h-fix current permissions:crw-rw-r-- 1 root root 189, 1025 May 5 02:48 /dev/bus/usb/009/002 ft232h-fix current mode is 664 need 666 for non-root pyftdi access ft232h-fix udev rule already present in /etc/udev/rules.d/11-ftdi.rules ft232h-fix reloading udev rules and re-triggering... sudo password for abbeefai: ft232h-fix permissions after reload:crw-rw-rw- 1 root root 189, 1025 May 5 02:54 /dev/bus/usb/009/002 ft232h-fix SUCCESS — mode is now 0666. ft232h-fix next: restart your docker container so the new permission is visible inside. Next, inside the Hailo docker container, we can launch the mb-powermon utility as follows: bash hailo virtualenv $ python3 mb-powermon.py --probe hailo,adafruit --csv mb-powermon-hailo-ina228-resnet50-20260504.csv If we re-run the hailortcli utility in a separate console within the Hailo docker container: bash hailo virtualenv $ hailortcli benchmark resnet v1 50.hef Starting Measurements...Measuring FPS in HW-only modeNetwork resnet v1 50/resnet v1 50: 100% | 20577 | FPS: 1371.25 | ETA: 00:00:00Measuring FPS and Power on supported platforms in streaming mode HailoRT warning Using the overcurrent protection dvm for power measurement will disable the overcurrent protection.If only taking one measurement, the protection will resume automatically.If doing continuous measurement, to enable overcurrent protection again you have to stop the power measurement on this dvm.Network resnet v1 50/resnet v1 50: 100% | 20580 | FPS: 1371.46 | ETA: 00:00:00Measuring HW LatencyNetwork resnet v1 50/resnet v1 50: 100% | 4036 | HW Latency: 3.20 ms | ETA: 00:00:00=======Summary=======FPS hw only = 1371.26 streaming = 1371.47Latency hw = 3.19887 msDevice 0000:c5:00.0: Power in streaming mode average = 3.95935 W max = 3.95935 W hailo virtualenv $ hailortcli benchmark resnet v1 50.hef Starting Measurements...Measuring FPS in HW-only modeNetwork resnet v1 50/resnet v1 50: 100% | 20577 | FPS: 1371.26 | ETA: 00:00:00Measuring FPS and Power on supported platforms in streaming mode HailoRT warning Using the overcurrent protection dvm for power measurement will disable the overcurrent protection.If only taking one measurement, the protection will resume automatically.If doing continuous measurement, to enable overcurrent protection again you have to stop the power measurement on this dvm.Network resnet v1 50/resnet v1 50: 100% | 20580 | FPS: 1371.46 | ETA: 00:00:00Measuring HW LatencyNetwork resnet v1 50/resnet v1 50: 100% | 4232 | HW Latency: 3.15 ms | ETA: 00:00:00=======Summary=======FPS hw only = 1371.26 streaming = 1371.48Latency hw = 3.14771 msDevice 0000:c5:00.0: Power in streaming mode average = 4.02821 W max = 4.02821 W NOTE: You may notice that hailortcli is reporting identical average and max values e.g., 3.95935 == 3.95935, 4.02821 == 4.02821 . As explained in Part 1, this is a signature of contention when two applications read the Hailo power API simultaneously — which is exactly what’s happening here, since mb-powermon.py is also polling the API for comparison. I recommended against this in Part 1, and I’m doing it deliberately here only to overlay both measurements on the same plot. The Hailo values shown should be treated as approximate references, not ground truth. For a clean Hailo reading, run hailortcli alone, as in Part 1. While this is running, you will see something similar to the following video playing at 10x speed : In this video, I am benchmarking resnet50 twice on the same Hailo module. If we convert the output.csv file to a user-friendly.html, we can plot power and temperature for both runs and overlay Hailo’s reported averages: bash hailo virtualenv $ python3 csv-to-html-plot.py --input mb-powermon-hailo-ina228-resnet50-20260504.csv --output mb-powermon-hailo-ina228-resnet50-20260504.html The first thing that jumps out with these results is that the INA228 measurements are slightly higher than Hailo’s own measurements. This is the expected behavior. Each shunt resistor drops a small voltage across itself, leaving the load downstream with slightly less supply voltage. Since P = V · I, the load consumes slightly less power, and any downstream sense resistor reads correspondingly lower. The INA228 sits upstream of Hailo’s internal shunt, which contributes to the readings being higher. I am very happy with these results ConclusionIn this article, we have found a working solution to measure power for M.2 AI accelerator modules. At a total price of ~$60 FT232H + INA228 + cable + ElmorLabs PCIe adapter , the Adafruit solution is a cost-effective solution. One improvement could be a casing to encapsulate the FT232H and INA228 boards. With a validated power measurement methodology, we can now compute the metric that matters for edge AI: FPS per watt. On resnet50, the Hailo-8 delivers ~1371 FPS at ~4.0 W — roughly 343 FPS/W . This figure becomes our first reference point against which other M.2 AI accelerators can be measured in future articles, using the same methodology applied here. Alternate PCIe power insertion adapterSince this article was published, the ElmorLabs PCIe power insertion adapter, which exposes the 3V3 rail as a jumper, has been out of stock. I found another working alternative. The ADTLink R33G PCIe power insertion adapter also exposes the 3V3 rail as a jumper, and also works with the methodology described in this article. On this PCIe riser, the important connections to make are: - V+ connected to 3V3 red cable - inner pin - V- connected to 3V3 black cable - outside pin - 2026/05/05 : Initial Draft - 2026/06/15 : Document alternate PCIe riser Read more javascript:void 0