Putting The Mooshimeter To Sleep With A Bit Of Mercury

May 8, 2018 by Tom Nardi 33 Comments

If you haven’t heard of it, the Mooshimeter is a two channel multimeter that uses your smartphone as a display over Bluetooth 4.0. The ability to simultaneously monitor voltage and current is rather unique, and the fact that you aren’t physically tethered to the thing makes it ideal for use in hard to reach or even dangerous locations. The promotional material for the Mooshimeter shows users doing things like leaving the device inside the engine compartment of a car while they drive around and take readings about the vehicle’s electrical system.

All that sounds well and good, but at the end of the day, the Mooshimeter is probably not going to be your primary multimeter. It’s going to stay on a shelf until a task befitting its unique abilities comes along. Unfortunately, as [nop head] found, that can be a problem. Like many modern devices, the Mooshimeter doesn’t actually turn off. It just sits there draining its battery until you’re ready to use it. Which of course means that when you’re finally ready to pull the thing out and put it to use, you get a low battery warning and need to put new AAs in it. First World problems.

The fix for this thoroughly modern problem is delightfully old school: a mercury tilt switch.

Using a small spacer made of Kapton tape, [nop head] was able to isolate the battery contacts from the PCB itself. He then soldered the mercury switch in place between them, making sure to position the bulb vertically. When the Mooshimeter is right side up, the mercury flows down and bridges the contacts; but when the device is inverted the contact is broken and the batteries stop draining. He still has to remember to put the Mooshimeter face down when he’s done with it, but it’s better than dealing with constant dead batteries.

There was a lot of initial interest in the Mooshimeter when it was announced in 2014, but we’ve seen precious little of it since. It certainly seems neat, but perhaps it’s a bit too niche for its own good? If Mooshimeter fulfills a critical role in your tool set, let us know in the comments below.

Hackaday Links: December 10, 2017

December 10, 2017 by Brian Benchoff 14 Comments

We have a contest going on right now challenging you to do the most with a coin cell. There are already quite a few interesting entries, and a few Hackaday writers are getting into the action by asking the question, ‘how do you open up a coin cell?’. The first thoughts were to open a lithium coin cell up while submerged in oil, but eBay came to the rescue with the cases for CR2025 cells. Of course that’s a thing.

Also falling into the, ‘of course that’s a thing’ category, there’s a project on Hackaday.io to execute arbitrary code on a calculator. A small group of calculator hackers have discovered an exploit on a line of Casio calculators running the obscure nX-U8/100 architecture. Right now, there’s not much to the project — just an LCD filled with bits of memory. However, this is a project we’re keenly watching, and we can’t wait to see what comes of it.

Hold onto your butts, because the ultimate multimeter is here. [Dave Jones] of the EEVBlog has released the 121GW Multimeter on Kickstarter. What’s cool about this meter? SD card logging, the ability to send data over Bluetooth, a 15V diode test voltage, a burden voltage display, and a whole bunch of hackable features. If you have a Fluke on your Christmas list, you would do well to check out the 121GW.

Also on Kickstarter, a new LattePanda board has been released. What’s a LattePanda? It’s a small single board computer built around a low-voltage Intel processor. This board features an Intel m3-7Y30 processor, comparable to the processor you’d get in a proper laptop that doesn’t have an i3, 8 gigs of DDR3, 64 gigs of eMMC, 802.11ac, BlueTooth 4.2, USB 3.0 with a Type C connector, HDMI, and a whole bunch of GPIOs. Yes, it runs Windows (but why would you?). If you need a somewhat beefy x86 system in a small form factor, there ‘ya go.

We’ve seen 3D printed remote-controlled airplanes, but never one this big. The guys at Flite Test printed a 1.6 meter Spitfire. It’s got flaps, it’s got retracts, and it’s friggin’ huge. The files for the print came from 3DLabPrint, and it flies beautifully, despite being a Spitfire. Want to see the video? Here ya go.

The Worst Piece Of Test Equipment You’ve Got To Try Hacking

November 28, 2017 by Jenny List 130 Comments

A brand new meter in its blister pack

I have a fascination with the various online vendors of electronics and other manufactured goods from China. Here are listed the latest wonders from Shenzhen or wherever, which you can have for a surprisingly reasonable price, with the mild inconvenience of a three week wait for the postage.

A particular pastime of mine is to look for the bottom end of the market. Once I’ve picked up the items I came to order I’ll trawl around with the search with low price first and see what can be had for a few dollars. Yes, I take a delight in finding absolute trash, because just sometimes that way you can find a diamond in the rough.

So when I was shopping for a multimeter recently I took a quick look to see what the cheapest model from that particular supplier was. For somewhere around £2.50 or just over $3, I could have a little pocket analogue multimeter, the kind of “My first multimeter” that one might have found in the 1980s. They weren’t too bad, I thought, and ordered one for less than a pint of beer in a British pub.

Continue reading “The Worst Piece Of Test Equipment You’ve Got To Try Hacking” →

Why You Shouldn’t Quite Forget The Moving Coil Multimeter

November 8, 2017 by Jenny List 80 Comments

Did any of you have an AWS multimeter? Was it the best? Radio-electronics magazine, August 1981. — Did any of you have an AWS multimeter? Was it the best? Radio-Electronics magazine, August 1981.

If you were to ask a random Hackaday reader what their most fundamental piece of electronic test equipment was, it’s likely that they would respond with “multimeter”. If you asked them to produce it, out would come a familiar item, a handheld brick with a 7-segment LCD at the top, a chunky rotary selector switch, and a pair of test probes. They can be had with varying quality and features for anything from a few dollars to a few hundred dollars, though they will nearly all share the same basic set of capabilities. Voltage in both AC and DC, DC current, resistance from ohms to mega ohms, and maybe a continuity tester. More expensive models have more features, may be autoranging, and will certainly have better electrical safety than the cheaper ones, but by and large they are a pretty standard item.

If Hackaday had been around forty years ago and you’d asked the same question, you’d have had a completely different set of multimeters pulled out for your inspection. Probably still a handheld brick with the big selector switch, but instead of that LCD you’d have seen a large moving-coil meter with a selection of scales for the different ranges. It would have done substantially the same job as the digital equivalent from today, but in those intervening decades it’s a piece of equipment that’s largely gone. So today I’m going to investigate moving coil multimeters, why you see them a lot less these days than you used to, and why you should still consider having one in your armoury. Continue reading “Why You Shouldn’t Quite Forget The Moving Coil Multimeter” →

The Cheapest Meter On Banggood

July 17, 2017 by Al Williams 61 Comments

According to [pileofstuff], he didn’t really need another digital multimeter. However, when he saw a DT-832 meter on Banggood for the princely sum for $4.99 he wondered just what kind of meter you’d get for that price. You can see his conclusions in his recent video (below). He does make it clear, by the way, that he wasn’t paid for the review or given the meter. He just decided to see what $5 would buy in a meter.

Depending on your predisposition to cheap Asian electronics, you may or may not be surprised. After all, for $5 you can’t expect a top-of-the-line lab instrument. The device measures AC and DC voltage, DC amperage, ohms, transistor beta, and has a diode tester and continuity buzzer. It also has some frequency measurement capability. You can’t be too surprised it doesn’t auto range, though. To be fair, although he mentions Banggood as the source of the meter, a quick Google search shows you can get them from all the usual sources, and the price is down to $3.73 as long as you let them ship it from Canada.

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

June 4, 2017 by Bryan Cockfield 23 Comments

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.

Continue reading “Hackaday Prize Entry: Safety Glasses Are Also Hands-Free Multimeter” →

From 1950s Multimeter To Internet Connected Clock

March 4, 2017 by Jenny List 6 Comments

We’ve seen many clocks here over the years. Some of them are conventional, some esoteric. So it’s not often that we see something novel in the world of timekeeping.

Strictly speaking, [Giulio Pons]’s clock project isn’t new at all. He’s taken a broken multimeter from the 1950s, and with the help of an Arduino Nano and an ESP8266 module, converted it into a clock that indicates the time on the multimeter’s moving-coil meter. He’s wired the multimeter’s front panel controls to the Arduino to operate the thing, and given it a speaker to play alarm sounds. A PIR motion detector activates the clock. In the hours of darkness, a photoresistor brings up a light. Time setting is automatic via the internet. [Giulio] previously experimented with an RTC module but found the network connection made changing time settings easier.

It’s by no means the perfect timepiece. For instance, [Giulio] found that driving the meter from a PWM pin gave different readings depending on the PSU load from other parts such as the light. But the clock does work, and has breathed new life into what might otherwise have remained a piece of junk.

Those of you with long memories might remember a similar project from a few years ago that used unmodified multimeters to display time as voltage. And of course, there are always frequency counter clocks.