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Are electronic devices really in a very low power mode when on stand-by ?
Also, how much energy am I wasting for powering devices when not in use ?
I wanted to check it out and decided to build a device capable to detect stand-by mode of my electronic devices and start metering energy used. All this had to be done automatically without my intervention. Metering would start upon entering stand-by and stopped upon exiting.
To do so I needed an energy meter and a current gauge to monitor the current of mains supplied devices and start/stop metering.
For the meter I first looked for silicon, of course. Energy metering is a hot issue with a lot of chip makers and many of them supply cheap solutions.
The project was proceeding when recently I was lucky enough to find two electromechanical meters at a local special trash collecting center (electrical, white goods, furniture).
Actually there should be a plenty of these scrap meters available here as the local electric company is replacing these meters with remotely controlled electronic meters.
I took them along with two VCRs and a printer. The first meter I opened and dismantled to satisfy my inner primary need. The second meter I decided to use in place of the silicon-based one; also, the ready made electromechanical meter solved the calibration issue.
This PopSci contest made me hurry and change priorities in my to-do-list, so here is my design.
Schematic V0.2 is an improved version of the electronic control box over the previous one. I added a potentiometer to set the hysteresis level. This helps discriminate power on vs. stand-by for noisy power supplies like some switchers are. This also helps get firmer metering on/off states.
The schematic shows in red the differences with respect to previuos version.
Also, how much energy am I wasting for powering devices when not in use ?
I wanted to check it out and decided to build a device capable to detect stand-by mode of my electronic devices and start metering energy used. All this had to be done automatically without my intervention. Metering would start upon entering stand-by and stopped upon exiting.
To do so I needed an energy meter and a current gauge to monitor the current of mains supplied devices and start/stop metering.
For the meter I first looked for silicon, of course. Energy metering is a hot issue with a lot of chip makers and many of them supply cheap solutions.
The project was proceeding when recently I was lucky enough to find two electromechanical meters at a local special trash collecting center (electrical, white goods, furniture).
Actually there should be a plenty of these scrap meters available here as the local electric company is replacing these meters with remotely controlled electronic meters.
I took them along with two VCRs and a printer. The first meter I opened and dismantled to satisfy my inner primary need. The second meter I decided to use in place of the silicon-based one; also, the ready made electromechanical meter solved the calibration issue.
This PopSci contest made me hurry and change priorities in my to-do-list, so here is my design.
Schematic V0.2 is an improved version of the electronic control box over the previous one. I added a potentiometer to set the hysteresis level. This helps discriminate power on vs. stand-by for noisy power supplies like some switchers are. This also helps get firmer metering on/off states.
The schematic shows in red the differences with respect to previuos version.
How-green-schematic.zip137 KB
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Signing UpStep 1Caution, safety first !
Before starting, you must be absolutely aware that this thing is powered from the mains and
as such it could kill you, cause damage or injuries. If you are not really skilled at mains
powered electronics and related safety building practice and are not well aware of the risk related, you are suggested to have a friend help you with this project.
Also, as a general rule, when you are working on dangerous things always have someone next to you instructed on what to do if something goes unexpectedly.
Most parts of the circuit should not be considered safe to touch when the circuit is powered on.
Keep low voltage and high voltage wiring as separate as possible. The relay is the point where the two worlds are closer. Choose a good relay and have the wires soldered firmly. Tape well and possibly use heat-shrink tube.
These notes are not just to scare or bother anyone, but I absolutely want that fun does not turn
into grief.
as such it could kill you, cause damage or injuries. If you are not really skilled at mains
powered electronics and related safety building practice and are not well aware of the risk related, you are suggested to have a friend help you with this project.
Also, as a general rule, when you are working on dangerous things always have someone next to you instructed on what to do if something goes unexpectedly.
Most parts of the circuit should not be considered safe to touch when the circuit is powered on.
Keep low voltage and high voltage wiring as separate as possible. The relay is the point where the two worlds are closer. Choose a good relay and have the wires soldered firmly. Tape well and possibly use heat-shrink tube.
These notes are not just to scare or bother anyone, but I absolutely want that fun does not turn
into grief.
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Good instructable on building an AC current meter, though.
I measured the electricity consumption of my entertainment electronics in the state they are when not used.
- Monitor (off) 0W
- Computer (off) 3W (always provides electricity to rear panel USB ports, only keyboard and mouse were attached)
- ADSL (off) 1W (the mechanical switch is between transformer and the device)
- Stereo (stand-by) 5W
And also the rarely used bedroom VCR draws 3W when in stand-by.These are all devices that are theoretically needed only for 8 hours max each day (assuming I spend 8h at work and 8h asleep).
During one year these devices would completely _waste_ as much electricity as a 90W incandescent light bulb does when left on for 1 month (likely more, since I don't need to use all of them for 8 hours every day). Luckily they are all connected with extension cords that are very easily accessible so I can unplug them when I don't use them without causing any decrease in the quality of my life.
Not that I consider quality of life a reason to waste electricity...
Exactly -- now think about it (maybe you have, but for others to see realize this).... Let's say there's one computer per person in the United States (theoretically, 300 million). Each will draw at least 3W (that's an assumption) - That's 900000 kilowatts. For one year, that's 7,776,000,000 Kilowatt hours!
For more perspective - that amount of energy is equivalent to 1,102,000,000 pounds of natural gas ASSUMING we can extract that energy with 100% efficiency (actual numbers are significantly lower). So it's like voting, you're small effort does count - especially if you tell someone else what effect it has :)
All of that so we can keep our computers plugged in and off. And yes, there's some large assumptions there - but even if you divided that in half - that's still a HUGE number. And my significant other laughs at me when I say I'd love to live off grid :P
And to finish off my mini rant... did you know about a third of America's engineers are retiring in three years (at least they're ready to). At the moment, the average engineer work load is something like 47.5 hours per week and rising every year. Of engineers surveyed, ~45% said elementary through high schools get a D or an F for prepping for engineering and prepping for engineering v. other carries. And staggering, 60% said D or F compared to other countries (which means any other country). Luckily the university scores were higher - but, it's still a problem that about half of those that begin in engineering washout typically due to unpreparedness.
Problem: Energy
Question: Who's going to work on this problem?
I dare you - ask a kinder gardener to draw a doctor... then a lawyer.... then ask, draw me an engineer. Here's a hint - one child in that class drew something for an engineer -- a person looking at a car with it's hood up but everyone could draw the doctor and the lawyer o.0
/rant (sorry, it's not directed at you - but energy just gets me fired up)
While I would agree that there is a disconnect between people understanding their energy consumption (in terms of dollars and kWh) there's also a problem with the amount of utility people enjoy as a result of that standby power. They *do* enjoy the ability to turn equipment on by remotes, to come home to an HVACed house set at the temperature that they want, to run large energy-inefficient devices and appliances (look at the prevalence of large trucks in the US and other nations for general transport needs).
When people both have more information on what their using and how much its costing, along with more exposure to the prices of delivering the energy they wish to consume, they will be in a position to make informed decisions on their energy usage. We're a long way from that.
You're absolutely right about the disregard for engineering, but engineers themselves are also to share part of the blame. We need to ensure the community understands what we do and where they receive the benefits of our services. A big part of the problem is the lack of face-to-face time with the community engineers have. Doctors, Lawyers, Accountants etc all spend a lot of time interacting with the community, Engineers generally do not.
Finally, we need to shift people away from being proud of being innumerate and make it something like illiteracy - something that should not be championed.
I wrote up a small article on Blackle and their claims when they first launched. Additionally, the owners of Blackle egreriously claimed (via emails that were forwarded globally) that Blackle was a Google creation and not an entrepreneurial venture using environmental claims as a cover.
End of the day the values that are being claimed are on experimental data from 10 years ago. These need to be rigorously checked for accuracy - as all science requires.
As noted below LCDs use more power to show black (even if only marginally). LCDs are continually backlit (a good portion of the energy goes here) and the RGB components darkened by applying a voltage across each crystal to be twisted to prevent the light being visible.
More interesting will be the energy savings when OLED based displays are widely available at cost competitive prices. Then dark screens really will have the ability to save energy (and money) - and be more efficient than CRTs into the bargain.
However, many modern monitors are utilising a technology which involves dynamically changing the brightness of the backlight depending on whether a dark scene or a light scene is being displayed. This it to give high brightness to light scenes, while still giving good contrast on dark scenes - an overall better gamma throughput.
This means that for these monitors, dark scenes ultimately use less power.
How green are my green electronics?
(Wonders why conjugating verbs in one's own language is so tough for people)
It was a sort of divertissement.
The plugs here are very safe as it is practically impossible to come in contact with the live metallic part while plugging in. Also, the sockets in the wall require that all three contacts enter the socket at the same time thus preventing young experimenters from putting wrong things in the socket.
The female (right) can accept 16A larger holes and 10A (smaller holes) plugs. Ground is center and there's no polarity (Line and Neutral can be exchanged). We run on 50Hz while US and some other countries run on 60Hz.
As we run on 220Vac, for a given power requirement we use smaller cords (less Amps are required).
Hola !