Agilent LCR Meter Teardown

Since 1999, one of the more popular manufacturers of test equipment has been Agilent, the spun-off former instrument division of Hewlett-Packard. From simple multimeters to fully-equipped oscilloscopes, they have been covering every corner of this particular market. And, with the help of [Kerry Wong] and his teardown of an Agilent LCR meter, we can also see that they’ve been making consistent upgrades to their equipment as well.

The particular meter that [Kerry] took apart was an Agilent U1731B, a capable LCR (inductance, capacitance, resistance) meter. He had needed one for himself and noted that while they’re expensive when new, they can be found at a bargain used, but that means dealing with older versions of hardware. For example, his meter uses an 8-bit ADC while the more recent U1733 series uses a 24-bit ADC. The other quality of this meter that [Kerry] made special note of was how densely populated the circuit board is, presumably to save on the design of a VLSI circuit.

While we don’t claim to stump for Agilent in any way, it’s good to know that newer releases of their equipment actually have improved hardware and aren’t just rebadged or firmware-upgraded versions of old hardware with a bigger price tag attached. Also, there wasn’t really any goal that [Kerry] had in mind besides sheer curiosity and a willingness to dive deep into electronics details, as those familiar with his other projects know already.

Monitor Power Consumption of Low-Power Devices

Perhaps the most important consideration to make when designing a battery-operated device of any kind is the power consumption. Keeping it running for longer between battery changes is often a key design point. To that end, if you need to know how small programming changes will impact the power consumption of your device then [Daniel] has a great tool that you might find helpful: an ESP8266-based live power meter.

The power meter itself is battery-powered via a 600 mAh battery and monitors an e-paper module, which also displays information about power consumption. It runs using a NodeMCU and measures voltage and current across a 100-ohm resistor to calculate the power use, although the resolution does start to get noisy when the device is in standby/sleep mode. One presumes this could be solved by changing the value of the resistor in order to get more accurate measurements at the expense of losing accuracy during moments of high power consumption.

While this power monitor was built specifically to monitor power consumption on this particular e-paper display project, it should be easily portable into other battery-based systems that need fine tuning in order to maximize battery life. As a bonus, the display is already included in the project. There are ways of getting even more information about your battery usage, although if power consumption is important than you may want to stick with a more straightforward tool like this one.

Digital Panel Meter Tear Down

[Big Clive] had some 22mm digital AC voltmeters, made to put in a panel. There was a time when this would have been a significant pain, since it required you to make a large square hole. Of course, in a world of CNC and 3D printers that isn’t as big a deal as it used to be, but the ones [Clive] has are nice because having a round footprint you can drill a hole for them with a hole saw or a stepped bit. Of course, he wasn’t satisfied to just use these inexpensive meters. He had to tear one apart to look inside. You can see his review and teardown in the video below. The meters are available in a range of AC voltages, although [Clive] didn’t think the ones he had would safely handle their rated maximum.

Inside, the modules reminded us of cordwood construction in a way. Most of the electronics are on a small round board. But several components connect to the board and the bottom cap in a vertical orientation. The meters are available in several colors, but [Clive] likes the red ones as they appear brighter than the others. The voltage reading compared favorably to a Fluke meter.

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Repurposing Moving Coil Meters to Monitor Server Performance

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.

AsĀ [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 psutilĀ and parsing the results for display on the meters.

Looking for more analog meter goodness? We saw a similar CPU load meter a few months back, and there was this mash-up of Nixies and old meters for a solar energy CEO’s desk.

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How Smart is the Grid?

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.

A Cutler-Hammer industrial breaker ominously predicts the coming confusion in the smart grid arena.
Photo by Bryan Cockfield

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.

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Hackaday Prize Entry: Safety Glasses Are Also Hands-Free Multimeter

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.

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Life-Size Vu Meter Gets the Party Started

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.

[Est]’s smaller version of the VU meter has been featured here before, if you’re looking to enhance your music-listening or party-going experiences with something a little less intimidating. We’ve also seen VU meters built directly into the speakers and also into prom dresses.