Wednesday, January 20, 2016

Extending Energy monitoring - ADS1115 Grove module and ADS1115 Featherwing

After selling a few kits and populated boards of the NodeMCU Energy Monitor on Tindie, I started receiving feedback from people in the real world using my design. One of the main requests was the ability to support more channels, the other was miniaturisation suitable for fitting in 1 or 2 unit DIN Rail enclosures.

I addressed the request for channels by developing my own energy monitoring specific ADS1115 breakout. In addition to the core IC it includes 3.5mm stereo sockets for connecting the popular YHDC CT sensor and a couple of Grove connectors for chaining multiple boards together. Using this mechanism and the core NodeMCU energy monitor, one can monitor upto 7 current channels.

The issue of miniaturization is adressed by choosing a smaller form factor and feature rich ESP8266 breakout, namely the Adafruit feather. As a side effect we gain access to all the other boards using the feather form factor and all the other stackable featherwings.

During the design of the Energy Monitor Featherwing I integrated the ADS1115 onto the same board instead of using a breakout  (switched to 0603 parts to make it more compact) and used an SMD version of the Recom 5V Buck converter.

The featherwing can be mounted with stackable connectors under the Adafruit feather. Leaving the top free for display OLED for realtime power display or just weather or bitcoin prices vs energy usage.

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