Resource monitoring solution

Electricity, Gas and Water – three resources that are vital in our daily lives. Monitoring them using modern technology helps with conservation, but the real impact comes when we use the available data to reduce wasteful usage over time. [Sébastien] was rather embarrassed when a problem was detected in his boiler only during its annual inspection. Investigations showed that the problem occurred 4 months earlier, resulting in a net loss of more than 450 cubic meters, equivalent to 3750 liters per day (about 25 baths every day!). Being a self professed geek, living in a modern “connected” home, it rankled him to the core. What resulted was S-Energy – an energy resource monitoring solution (translated) that checks on electricity, gas and water consumption using a Raspberry Pi, an Arduino, some other bits of hardware and some smart software.

[Sébastien] wanted a system that would warn of abnormal consumption and encourage his household folks to consume less. His first hurdle was the meters themselves. All three utilities used pretty old technology, and the meters did not have pulse data output that is commonplace in modern metering. He could have replaced the old meters, but that was going to cost him a lot of money. reflective-power-meter-sensorSo he figured out a way to extract data from the existing meters. For the Electricity meter, he thought of using current clamps, but punted that idea considering them to be suited more for instantaneous readings and prone for significant drift when measuring cumulative consumption. Eventually, he hit upon a pretty neat hack. He took a slot type opto coupler, cut it in half, and used it as a retro-reflective sensor that detected the black band on the spinning disk of the old electro-mechanical meter. Each turn of the disk corresponds to 4 Watt-hours. A little computation, and he’s able to deduce Watt-hours and Amps used. The sensor is hooked up to an Arduino Pro-mini which then sends the data via a nRF24L01+ module to the main circuit located inside his house. The electronics are housed in a small enclosure, and the opto-sensor looks just taped to the meter. He has a nice tip on aligning the infra-red opto-sensor – use a camera to check it (a phone camera can work well).

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Monitoring your Gas Consumption with a JeeNode and a nRF24L01+

[Sven337] just blogged about a gas consumption monitoring setup he finished not long ago. As his gas meter was located outside his apartment and nowhere near any electrical outlet, a battery-powered platform that could wirelessly send the current consumption data to his Raspberry Pi was required. His final solution therefore consists of a JeeNode coupled with the well known nRF24L01+ wireless transmitter, powered by 3 supposedly dead alkaline batteries.

[Sven337] carefully looked at the different techniques available to read the data from his meter. At first he had thought of using a reflective sensor to detect the number 6 which (in France at least) is designed to reflect light very well. He then finally settled for a magnetic based solution, as the Actaris G4 gas meter has a small depression intended for magnetic sensors. The PCB you see in the picture above therefore has a reed sensor and a debug LED. The four wires go to a plastic enclosure containing the JeeNode, a couple of LEDs and a reset switch. Using another nRF24L01, the Raspberry Pi finally receives the pulse count and reports it to an eeePC which takes care of the storage and graphing.