This repository contains the measurement hardware and firmware of the netzsinus project. The current hardware is still under development - you have to solder your own hardware. The hardware is, however, pretty simple and easy to build.

Our vision is to develop a network analyzer in the sense of DIN EN 50160. Currently, only the network frequency is measured, but other measurements such as voltage and harmonics will be included step-by-step.

The hardware consists of

• A 9VAC wall-wart power adaptor. I have only tested Ideal Power model DE-06-09, but others should also work.
• A STM32F4 Discovery board. This evaluation kit offers a Cortex M4 microcontroller which will become handy if we implement the harmonics analysis.
• An adapter board which contains the analog frondend and connects all the components.
• A raspberry pi which runs a simple Go daemon to read the data from the hardware and transmit it to https://netzsin.us.

The current design powers the STM32F4 from the Raspberry Pi. It would also be possible to power the system from the 9VAC power adaptor, but initial experiments showed distorsions in the sine wave caused by the bridge rectifier. A precision bridge rectifier setup could solve this.

Currently, you just have to solder your own hardware. But since the hardware is pretty simple this is an easy task. Please use this schematic:

The opamp is an TLC393 comparator. I used a protoboard and THT components to build this circuit as a shield for the STM32F4 discovery board. This is my setup:

The STM32F4 discovery costs around 15 Euro, the 9VAC adaptor around 5, everything else maybe 2 Euros.