Putting the Mooshimeter to Sleep with a Bit of Mercury

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.

Note the vertical orientation

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.

A Mountain of Prizes For Projects Using These Parts

Here’s your chance to bring some great stuff home from The Hackaday Prize. For the next 3 weeks we’ll be looking for the best entries using Atmel, Freescale, Microchip, and Texas Instruments parts.

Each of the four contests (yes, four running concurrently) will award the top 50 projects. That’s 200 in total being recognized. The odds are really in your favor — currently some of those lists have less than 50 projects on them — so enter yours right away! Scroll down to see the mountain of prizes that we have for this epic run.

Make Sure We Know About Your Entry

There are two things you need to do to be eligible for this pile of awesome stuff:

  1. Enter your project in the 2015 Hackaday Prize
  2. Leave a comment here with a link to your project and we’ll add it to the list

Do this by the morning of Monday, June 29th to make sure you’re in the running. We’ve been diligent about adding entries to the lists for Atmel, Freescale, Microchip, and Texas Instruments but at the rate new entries have been coming in it’s easy to miss one here or there. Don’t be bashful about asking to be added to these lists!

The prerequisite is to be using a part from one of these four manufacturers. We’ll be looking at these lists for projects using great ideas which have also been well-documented. Tells us why you’re building it, what it does, how you came up with the idea… you know, the whole story!

The Loot

Up for grabs in each of the 4 contests are:

3x Mooshimeters which is a multimeter that uses your smartphone as a wireless readout.

2x DS Logic analyzers which [Adam] reviewed a few weeks back.

15x Stickvise to hold your PCBs (and other things) in place while you work

A continuation of what we’re giving away in each of the 4 contests:

10x Bluefruit LE Sniffers to help you figure out what’s being transmitted by your BTLE devices

10x Cordwood Puzzles; grab your iron and tackle this head-scratching soldering challenge

10x TV-B-Gone is an iconic invention from [Mitch Altman]; one button turns off all TVs


The 2015 Hackaday Prize is sponsored by:

Crazy Whirlwind Pre-Hackaday Prize Launch Tour

The Hackaday Prize was about to launch but the date wasn’t public yet. I decided to do a pre-launch tour to visit a few places and to drop in on some of the Hackaday Prize Judges. It started in Chicagoland, looped through San Francisco for a hardware meetup and Hardware Con, then finished with visits to [Ben Krasnow’s] workshop, [Elecia White’s] studio, and the Evil Mad Scientist Laboratories.

The Prize is now running and it’s time for you to enter. Look at some of the awesome hacking going on at the places I visited and then submit your own idea to get your entry started. Join me after the break for all the details of the adventure.

Continue reading “Crazy Whirlwind Pre-Hackaday Prize Launch Tour”

Voltset Multimeters at World Maker Faire

Many tents at World Maker Faire were divided up into booths for companies and various projects. In one of these tents, we found the Voltset booth. [Tom, Ran, and Michael] were on hand to show off their device and answer any questions. Voltset is essentially a multimeter which uses your phone as a display. It connects to an Android phone via USB or an optional Bluetooth module.

Now we’d be a bit worried about the risk of damaging our phones with a voltmeter electrically connected via USB. However, many people have an old phone or retired tablet kicking around these days, which would be perfect for the Voltset. The Bluetooth module alleviates this problem, too – though it doesn’t fix the issue of what happens to the multimeter when someone decides to call.

Voltset isn’t new; both the Voltset team and the similarly specced  Mooshimeter were also at World Maker Faire last year. In the interim, Voltset has had a very successful Kickstarter. The team is accepting pre-orders to be shipped after the Kickstarter backers are sent their rewards.

voltset-2[Tom] told us that the team is currently redesigning their hardware. The next generation prototype board with more protection can be seen in the far right of the top photo. He also mentioned that they’re shooting for 5 digits of accuracy, placing them on par with many bench scopes. We’re skeptical to say the least about 5 digits, but the team is definitely putting their all into this product. We’ll wait until the Kickstarter backers start getting their final devices to see if Voltset is everything it’s cracked up to be.

Measuring 185 µΩ In Circuit

meter

To measure resistance, you usually have to take the resistor to be tested out of the circuit, and sometimes that’s impossible. If you’re using a multimeter, measuring very small resistances is difficult to say the least. Combine both these problems – measuring microOhms in-circuit – and you have a problem that’s perfectly suited for the Mooshimeter.

Announced just a few weeks ago, the Mooshimeter is a two-channel multimeter that communicates with your cell phone over Bluetooth. It’s perfect for measuring current and voltage simultaneously, all while being tucked away in some place that’s either dangerous, inaccessible, or mobile.

The Mooshimeter team put together a great example of what can be done with their meter by measuring the resistance of a car battery grounding strap while behind the steering wheel. To do this, they put alligator clips across the grounding cable and clamped on a current meter.

Inside the car, they whipped out their cell phone and looked at the Mooshimeter’s output for the voltage and current measurement. The Mooshi app has an IV curve (with linear regression in the works), so simply dividing the current and voltage gives them the resistance of the battery’s grounding cable.

It’s a very cool and extremely simple demonstration of how cool the Mooshimeter actually is. Video of the demo below.

Continue reading “Measuring 185 µΩ In Circuit”

Mooshimeter: The ‘Why Didn’t I Think Of That’ Multimeter

Despite how useful multimeters are, there are a lot of limitations you just don’t think about because they’re the way electronic measurement has always been done. Want to measure voltage and current simultaneously? Better get two meters. Measuring something in a dangerous, inaccessible, or mobile place? You could rig up a camera system to show the meter’s display on a monitor, you know.

Mooshimeter is the better way of doing things. It’s a multichannel multimeter that communicates with your cell phone over a Bluetooth connection. With two channels. the Mooshimeter makes it easy to graph voltage against current to plot a beautiful IV curve on your smart phone. Being a wireless multimeter means you can stick the Mooshi inside a robot and get instantaneous feedback of how hard you’re driving your motors.

Far from being a two-trick pony, the Mooshimeter is actually a pretty good multimeter by itself. It can handle 600V and 10A with 24 bits of resolution. Here are the complete specs. The Mooshimeter is available for preorder here for $100 USD.