I just released the first version of an INA226 based smart shunt. It's a cheap DIY altrernative to a Victron SmartShunt and can be built by anybody who can flash an ESP MCU and solder some components to a perfboard. You can find the code, some firmware files and a documentation on how to build the hardware on GitHub https://github.com/kscholty/SmartShuntINA226.
The INA226 is a shunt amplifier with an SPI interface. It can measure the small voltage drops that are produced by shunt resistors. My contribution is mainly the software that interfaces with the amplifier and implements an interface to the victrron world (or via modbus for other applications) and a hint which components to use to build the required hardware.
The current version of the software supports a PZEM-017 style modbus interface or alternatively the Victron Ve.Direct protocol. The Hex variant of that protocol is only implemented as far as it's required for connecting the shunt to a Victron GX system. It's working fine on my VenusOs RapberryPi and the Multiplus II GX I use in my production system.
It also offers a web based interface for configuration and human interaction.
I also started working on a VenusOs service that can handle this Shunt and also PZEM-017 sensors, but it's not finished yet. Let me know if you would find that useful, then I will polish it up and post it on GitHub as well.
I hope you find it useful and would like to hear your feedback.