Wireless Energy Monitor with MSP430

Description

This project has been a byproduct of the larger "Smart Greenhouse" project. With a ridiculously simple adaptation to the wireless code used for the sensor node in the other project, I've created a simple platform to measure the actual electricity usage using the pulses of red light emitted by the led on the smart meter.

Milestones of this project:
- Test wireless connection and send counter value when a button is pressen. (finished)
- Use phototransistor to detect red flashes. (finished)
- Determine messaging protocol - push/pull and transmitted data (currently in progress)
- Write client web app to show usage statistics using D3js. (not started yet)
- Shrink device to smaller PCB with a more permanent purpose. (not started yet)

Details

This project is actually just a "quick hack" to monitor my energy wirelessly. As I have ordered approx 20-30 nrf24l01+ dongles, I have plenty wireless dongles to spare. I use a simple MSP430 launchpad with the MSP430G2553 microcontroller to give the sensor its "brain". I am thinking of adding a RTC to the system to send a timestamp with every counter value.

The system uses the red light pulses emitted by the smart meter to determine the current electricity consumption. Each pulse corresponds to 2Wh, so 500 pulses are 1KWh.

To prevent that the wireless link wreaks havoc with the counting process, I've decided to transmit a counter value for each pulse. This counter on the launchpad increases with every pulse.

The current routine involves a while(!event) loop to wait for the red pulse. I want to use one of the Low Power Modes (LPM3 or LPM4) to reduce battery usage.

Part of this project will be a webpage in Flask to show some statistics.

Components

1 × Launchpad 430 with MSP430G2553 The brains of the sensor

1 × TEMT6000 Photosensor A breakout found on eBay with a pullup resistor. Any phototransistor will do probably.

1 × USB power supply A power supply to power the launchpad. After reducing the power, a set of rechargable batteries will be used

1 × Wires and black tape Female to female dupont wires to attach sensor and 24L01+ and sensor. Black tape to stick sensor to meter.

1 × NRF24L01+ dongle A simple green wireless dongle with a loop antenna.

Project Logs

Collapse

Just a small proof of concept...
eelco.rouw • 04/16/2014 at 21:37 • 0 comments

This project is actually a spin off project from my smart greenhouse. I've been wondering how easy it would be to count the light pulses from my energy meter and give me a reading on the current amount of power used by our house.
The system has been super easy. A TEMT6000 module (photo transistor) gives a high pulse when the led of my energy meter pulses. This pulse is recorded by a simple script and a counter is incremented by one. Dividing the counter value by 500 yields the KWh's that have been made during first bootup.
The counter value is transmitted by a NRF24 module and is received by the raspberry pi. Using the time module and the GPIO/SPI/PiNRF24 modules the data is received and timestamped. Taking the time between two consecutive pulses yields the current power usage.
I am planning to do some on device storage. I'm currently thinking of:
1. Storing the latest values.
2. Aggregating to a daily, weekly, monthly and annual overview.
The new Tiva connected launchpad could also be very interesting as it already has networking support in Energia.
So far my new ramblings, hope to see you later.

View project log

Discussions