A 12V AC-AC source is required for true-power measurements (DIN Rail). A 12V DC source will power the system without allowing voltage, true-power or power factor measurements.

What is it?

Daughterboard for the Adafruit Feather series of microcontroller boards with ADS1115 and high-efficiency buck converter/rectifier onboard. The board is based of the proven NodeMCU Energy monitor design and provides the same functions in a more compact form factor.

Why did you make it?

This product addresses the major hassles I found with the NodeMCU energy monitor design, it is large and PCB manufacture costs a lot (compare NodeMCU version to Featherwing version) increasing the cost to the user and it works only with the NodeMCU limiting the users options in how they want to use it.

What makes it special?

Perfect fit for the Adafruit feather series of controllers, will only become more versatile as more products are added to this line from Adafruit. With the feather series the user can choose to log data locally via SD card and the Adalogger or send it out within the house via bluetooth or to the web via wifi. It is all about options. All the feather boards also have a battery backup built in, so the energy monitor will detect power outage and can trigger notifications.

Each Featherwing can monitor a unique combination of voltage-current waveforms, this allows stacking 3 Featherwings with different I2C addresses to obtain an affordable 3 phase-metering system. The sampling is not simultaneous however, I am designing SPI based systems which will allow true 3-phase metering.

Will also stack with the other Adafruit Featherwings being released.

ADC Choice

After some feedback from customers I have decided to allow choice between the ADS1015 and ADS1115 ADC's. The ADS1015 is cheaper and has higher sampling rate making it potentially a better choice for Energy Monitoring, however it is only 12 bit, still a better choice than the on-board 10bit ADC. The ADS1115 has been used for manufacturing a few boards already and is in stock, it is 16bit, but samples slower and is about twice as expensive as the ADS1015.

Calibration Video