Snazzy analog meters can lend a retro flair to almost any project, but these days they often seem to be retasked as indicators for completely different purposes than originally intended. That’s true for these Vu meters repurposed as gauges for a Raspberry Pi server, and we think the build log is as informative as the finished product is good-looking.
As [MrWunderbar] admits, the dancing needles of moving-coil meters lend hipster cred to a project, but getting his Vu meters to cooperate and display network utilization and disk I/O on his Raspberry Pi NAS server was no mean feat. His build log is full of nice details on how to measure the internal resistance of the meter and determine a proper series resistor. He also has a lengthy discussion of the relative merits of driving the meters using a PWM signal or using a DAC; in the end, [MrWunderbar] chose to go the DAC route, and the video below shows the desired rapid but smooth swings as disk and network usage change. He also goes into great depth on pulling usage parameters from psutil and parsing the results for display on the meters.
Marketing and advertising groups often have a tendency to capitalize on technological trends faster than engineers and users can settle into the technology itself. Perhaps it’s no surprise that it is difficult to hold back the motivation to get a product to market and profit. Right now the most glaring example is the practice of carelessly putting WiFi in appliances and toys and putting them on the Internet of Things, but there is a similar type of fiasco playing out in the electric power industry as well. Known as the “smart grid”, an effort is underway to modernize the electric power grid in much the same way that the Internet of Things seeks to modernize household appliances, but to much greater and immediate benefit.
To that end, if there’s anything in need of modernization it’s the electric grid. Often still extensively using technology that was pioneered in the 1800s like synchronous generators and transformers (not to mention metering and billing techniques that were perfected before the invention of the transistor), there is a lot of opportunity to add oversight and connectivity to almost every part of the grid from the power plant to the customer. Additionally, most modern grids are aging rapidly at the same time that we are asking them to carry more and more electricity. Modernization can also help the aging infrastructure become more efficient at delivering energy.
While the term “smart grid” is as nebulous and as ill-defined as “Internet of Things” (even the US Government’s definition is muddied and vague), the smart grid actually has a unifying purpose behind it and, so far, has been an extremely useful way to bring needed improvements to the power grid despite the lack of a cohesive definition. While there’s no single thing that suddenly transforms a grid into a smart grid, there are a lot of things going on at once that each improve the grid’s performance and status reporting ability.
It seems like the multimeter is never easy to see during a project. Whether it’s troubleshooting a vehicle’s electrical system and awkwardly balancing the meter on some vacuum lines and the intake manifold, or installing a new solar panel and hoping the meter doesn’t fall on the ground while the leads are in both hands, it seems like there’s never a good way to see the meter while actually using it. Some meters have a small magnet and strap that can be used to hang them temporarily, but this will only get you so far.
[Alain Mauer]’s entry into the Hackaday Prize looks to solve this glaring problem. Using a heads-up Bluetooth display mounted to a pair of safety glasses, a multimeter can be connected to the device in order to display its information directly to its user. Based on his original idea which used a normal pair of prescription glasses as its foundation, [Alain]’s goal is to reduce safety hazards that might arise when using a multimeter in an awkward or dangerous manner that might not otherwise be possible.
The device uses an Arduino Pro Micro to connect to the multimeter and drive the display. [Alain] notes that the real challenge is with the optical system, however. Either way though, this would be a welcome addition to any lab, workspace, or electrician’s toolbox. Be sure to check out the video of it in action after the break.
There’s nothing better than making a giant version of one of your hacks. That is, other than making it giant and interactive. That’s just what [Est] has done with his interactive VU meter that lights up the party.
The giant VU meter boasts a series of IR detectors that change the colors and modes of the meter based on where the user places their hands. The sensors measure how much light is reflected back to them, which essentially function as a cheap range finder. The normal operation of the meter and the new interactivity is controlled by a PIC16F883 and all of the parts were built using a home-made CNC router. There are two addressable RGB LEDs for each level and in the base there are four 3 W RGB LEDS. At 25 levels, this is an impressive amount of light.
The only useful data you’ll ever find is already digitized, but a surprising number of gauges and meters are still analog. The correct solution to digitizing various pressure gauges, electric meters, and any other analog gauge is obviously to replace the offending dial with a digital sensor and display. This isn’t always possible, so for [Egar] and [ivodopiviz]’s Hackaday Prize entry, they’re coming up with a way to convert these old analog gauges to digital using a Raspberry Pi and a bit of computer vision.
The idea behind this instrument digitizer isn’t to replace the mechanics and electronics, as we are so often wont to do. Instead, this team is using a 3D printed bracket that mounts a Raspberry Pi and camera directly in front of an analog gauge. Combine this contraption with OpenCV, and you have a device that’s just smart enough to look at a needle on a dial, convert that to a number, and save it to a file or send it out over WiFi.
It’s an extremely simple device for what [Egar] and [ivodopiviz] admit is a relatively niche application. However, if you only need digital measurements of an analog meter for a month or so, or you don’t want to mess up your steampunk decor, it’s an ingenious build.
When your passion is a sport that depends on Mother Nature’s cooperation, you need to keep a close eye on weather conditions. With this in mind, and not one to let work distract him from an opportunity to play, [mechanicalsquid] decided to build a wind-monitoring gauge with an old-school look to let him know when the wind is right for kitesurfing.
Being an aficionado of big engineering helped [mechanicalsquid] come up with a style for his gauge – big old dials and meters. We hesitate to apply the “steampunk” label to every project that retasks old technology, but it sure looks like a couple of the gauges he used could have been for steam, so the moniker probably fits here. Weather data for favorite kitesurfing and windsurfing locales is scraped from the web and applied to the gauges to indicates wind speed and direction. [mechanicalsquid] made a valiant effort to drive the voltmeter coil directly from the Raspberry Pi, but it was not to be. Servos proved inaccurate, so steppers do the job of moving the needles on both gauges. Check out the nicely detailed build log for this one, too.
A home weather station is great geek street cred. Buying a commercially available station will get you all the bells and whistles, but the look tends to the utilitarian. And then there’s the trouble of placing the sensor array somewhere. To solve both problems, [GradyHillhouse] built this unique weather station with analog meters.
Based on a Particle Photon pulling weather data from the forecast.io API, values for temperature, pressure and the like are sent to analog IO pins. Each pin has a meter with a trimmer pot for calibration and a custom printed label. There’s also a digital output that goes high when a severe weather alert is posted; that drives an LED behind the bezel of one of the meters. Everything is mounted in a walnut plaque which makes for a nice presentation. The video after the break details the build.