Live Energy Monitor Helps Plan Power-Hungry Appliance Use

July 20, 2021 by Donald Papp 8 Comments

There are a lot of good reasons to have a better understanding of one’s household power use, and that is especially true for those that do their own solar power collection. For example, [Frederick] determined that it would be more efficient to use large appliances (like a dishwasher or washing machine) when there was excess solar power available, but the challenge was in accessing the right data in a convenient way. His Raspberry Pi-based live energy monitor was the solution, because it uses an LED matrix to display live energy data that can be consulted at a glance.

Interestingly, this project isn’t about hacking the power meter. What this project is really about is conveniently accessing that data when and where it is best needed. [Frederick] has a digital power and gas meter with the ability to accept a small wireless dongle. That dongle allows a mobile phone app to monitor power usage, including whether power is being taken from or exported to the grid.

Since [Frederick] didn’t want to have to constantly consult his mobile phone, a Raspberry Pi using a Pimoroni Unicorn HAT HD acts as a glanceable display. His Python script polls the power meter directly over WiFi, then creates a live display of power usage: one LED for every 250 W of power, with the top half of the display being power used, and the bottom half representing power exported to the grid. Now the decision of when to turn on which appliances for maximum efficiency is much easier, not by automating the appliances themselves, but simply by displaying data where it needs to be seen. (This kind of thing, incidentally, is exactly the idea behind the Rethink Displays challenge of the 2021 Hackaday Prize.)

As for those of us without a digital power meter that makes it easy for residents to access power data? It turns out there is no reason a power meter’s wireless service interface can’t be sniffed with RTL-SDR.

WiFi Power Monitor

October 4, 2015 by Eric Evenchick 15 Comments

Building your own hardware to measure AC power isn’t a simple task. There’s a number of things to measure, including voltage, current, power, and power factor. The Atmel 90E24 is a single chip solution designed for this exact purpose. Connect a few components, and all the power data is available to a microcontroller over SPI.

[hwstar] built a custom power monitoring board based on this IC. His AC-Emeter will give you all the measurements you’d want, and includes an ESP12 module for data collection and WiFi connectivity. Aside from the Atmel 90E24 device, a high power and low resistance resistor is needed for shunt sense current measurement. An external module is used to convert mains voltage down to 5V to power the board.

Of course, working with mains voltages can be a dangerous endeavour. Fortunately, [hwstar] provides some tips on how to prevent “equipment from being BLOWN UP” along with the open source hardware and firmware.

[via Embedded Lab]

Hackaday Prize Entry: Real Time Power Monitoring

August 1, 2015 by Brian Benchoff 19 Comments

The Internet of Things promises real-time monitoring of appliances, HVAC, and just about everything else in the home. One of the biggest technologies behind this is the smart meter, an electrical meter that will tell you how much power you’re sucking down from the grid at any given moment. A meter need not be smart, though, because [jlbrian7]’s entry for the Hackaday Prize does the same thing without an entirely new meter.

[jlbrian]’s power monitor is a non-intrusive monitor for electrical systems, allowing anyone to retrofit an electrical meter – or just a single breaker panel – with smart meter tech. It uses a small current transformer to monitor the amperage running through a wire. By sending that information to the Internet, anyone with this system gets power monitoring with much higher temporal resolution than what the power company provides in a monthly bill.

As a nice little addition to his Power Monitor, [jlbrian] is adding a few environmental sensors to his data logging platform. This allows for a little bit of interpolation to figure out what all that power is actually being used for; if the power turns on and a few minutes later the temperature drops, there’s a pretty good chance the AC just went on.

The 2015 Hackaday Prize is sponsored by:

We Have A Problem: Household Electrical

March 26, 2015 by Mike Szczys 106 Comments

Hackaday, we have a problem. The electricity in your house is on. It’s always on. How fast are those kilowatt-hours ticking by and what is causing it? For most people the only measurement they have of this is the meter itself (which nobody looks at), and the electric bill (which few people actually analyze). Is it silly that people pay far more attention to the battery usage on their phone than the electricity consumption in their abode? I think it is, and so appears another great seed idea for Hackaday Prize entries.

A Better Way to Measure

The tough part of the problem here is getting at reliable data. Just yesterday we saw an incredible resource monitoring project that uses an optical sensor to measure the turning or the wheel in an electric meter. We’ve seen similar projects for meters that have a blinking LED, and a few other methods. But in many cases the electrical meter is outdoors which makes cheap, easily installed sensors a difficult goal to achieve. Even if we did, this still provides just one stream of data, the entire house.

Alternatively you could tap into the breaker box. We’ve seen [Bill Porter] do just that and there are some commercially available kits that include an octopus of clamp-style current sensors. This is a bit of an improvement, but still requires the user to open the electrical panel (don’t scoff at that statement, you know most people shouldn’t be doing that) to install them. I’m sure there are other methods that I’m missing and would love to hear about them in the comments below.

The Point

To sum up what I’m getting at here, think about the Kill-A-Watt which proved to be a very interesting hack. People liked not just seeing how much power something uses but extending where that data can be accessed. We don’t remember seeing any successful efforts to move the concept ahead a few generations. But if someone can crack that nut it could yield a wave of energy savings as people are able to be better connected with what is using a lot of electricity in their homes.

Your Turn (and Lessons from Last Week)

As with last week, now it’s your turn to come up with some ideas… wild, fantastic, good, bad, outlandish, let’s hear them. Better yet, document your idea on Hackaday.io and tag it with “2015HackadayPrize“. You can win prizes just for a well presented idea!

Speaking of last week, I shared the idea of adding some feedback to how long you’ve been in the shower. There were many opinions about the value and worthiness of that idea so I thought I’d close by covering some of them. Yes, there are much bigger wastes of water (and electricity in this case) in the world but why limit our solutions to only the largest offenders? The low-hanging fruit tends to be stuff a lot of people can understand and relate to. If we only talked about large-scale fixes (I dunno; reducing mercury emissions from power plants?) there is little momentum to crank-start a movement. If you found yourself thinking the ideas from this week and last are far too simple to win The Hackaday Prize that means you better get your project going. The world is hacked together by those who show up.

I’d love to hear suggestions for future installments of We have a problem. Leave those ideas in the comments and we’ll see you here next week!