# Introducing Mojo - A New Way to Measure Energy Usage in Battery-Powered Systems **URL:** \ **Category:** Blog Posts\ **Created:** [February 3, 2025, 3:45pm UTC](https://discuss.blues.com/t/introducing-mojo-a-new-way-to-measure-energy-usage-in-battery-powered-systems/2802 "2025-02-03T15:45:21Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![BluesDevRel](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.blues.com/bluesdevrel/32/899_2.png) [@BluesDevRel](https://discuss.blues.com/u/BluesDevRel)\ **Post date:** [February 3, 2025, 3:45pm UTC](https://discuss.blues.com/t/introducing-mojo-a-new-way-to-measure-energy-usage-in-battery-powered-systems/2802/1 "2025-02-03T15:45:22Z")
Mojo is a Notecard companion device that measures power consumption in battery-powered systems. * * * Read the full blog post at [https://blues.dev/blog/introducing-mojo-power-consumption-monitor](https://blues.dev/blog/introducing-mojo-power-consumption-monitor) and continue the discussion here. ---
**Author:** ![devElert](https://avatars.discourse-cdn.com/v4/letter/d/8e8cbc/32.png) [@devElert](https://discuss.blues.com/u/devElert)\ **Post date:** [February 4, 2025, 7:56pm UTC](https://discuss.blues.com/t/introducing-mojo-a-new-way-to-measure-energy-usage-in-battery-powered-systems/2802/2 "2025-02-04T19:56:01Z")
I’m curious to learn more about the protocol used between Notecard and Mojo. The datasheet for the LTC2959 mentions it runs as an I2C slave only, implying the Notecard is acting as I2C master. Does this have any implications when the host MCU is also acting as master? Do Notecard and host MCU’s (ESP32-S3 in my case) support multi-master operation on the I2C bus, and if so, how is timing and arbitration managed between multiple I2C masters? Thanks! ---
**Author:** ![darkerenergy](https://avatars.discourse-cdn.com/v4/letter/d/b5ac83/32.png) [@darkerenergy](https://discuss.blues.com/u/darkerenergy)\ **Post date:** [February 6, 2025, 12:33pm UTC](https://discuss.blues.com/t/introducing-mojo-a-new-way-to-measure-energy-usage-in-battery-powered-systems/2802/3 "2025-02-06T12:33:33Z")
Why isn’t the Mojo device supported for the LoRa Notecard? I’m so disappointed. This is exactly what I’ve been waiting for - except I can’t use it! ---
**Author:** ![RobLauer](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.blues.com/roblauer/32/1567_2.png) [@RobLauer](https://discuss.blues.com/u/RobLauer)\ **Post date:** [February 6, 2025, 2:44pm UTC](https://discuss.blues.com/t/introducing-mojo-a-new-way-to-measure-energy-usage-in-battery-powered-systems/2802/4 "2025-02-06T14:44:30Z")
> The datasheet for the LTC2959 mentions it runs as an I2C slave only, implying the Notecard is acting as I2C master. Does this have any implications when the host MCU is also acting as master? Do Notecard and host MCU’s (ESP32-S3 in my case) support multi-master operation on the I2C bus, and if so, how is timing and arbitration managed between multiple I2C masters? The I2C protocol supports multiple masters, and we’ve not seen any problems yet in any application.