Check out this SparkFun Digital Multimeter. Does it make your blood boil to see them ripping off Fluke by using the color yellow? From SparkFun’s side of the story that’s exactly what’s happened here. They have a shipment of 2000 of these things stuck in customs. The trademark being infringed upon can be found in their article. Fluke owns the trademark on multimeters with a dark face and yellow border. Great. This seems like a wonderful idea, right up there with Apple owning tablets that are shaped like a piece of paper.
Okay, so if you’re not crying big fat tears for Fluke being taken advantage of in this way let’s talk about more immediate issues than fixing trademark, patent, copyright, and all of the other screw-the-little-guy type of laws (not that SparkFun is necessarily the little guy but you know what we mean). The DMMs sitting in a warehouse are costing SparkFun $150 per day. We believe they have no option of choosing a warehouse with a lower cost as we must be talking a pallet or two, right? The only two options they do have are shipping them back to China where they were manufactured, or having them destroyed. The former will cost more in re-import tariffs than the cost of the product, and the latter comes with a $150/hour disposal fee and no metric on which to judge how long it would actually take. We hate seeing this kind of waste, but sure enough 2000 DMMs are headed for the shredder in a couple of days.
We know you already have your flaming sword in hand, but simmer down for just a second. Fluke makes great products, ask anyone. And companies the world over defend their trademarks. Hopefully there will soon be a positive response from Fluke on this one. If you would like to politely encourage them to do the right thing we found Fluke’s Facebook page URL in the SparkFun comments thread. Both are worth browsing.
[Thanks Chris via Reddit]
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.
[Henryk Gasperowicz], the wizard of electrons who makes LEDs glow for no apparent reason, has put up another one of his troll physics circuits. We have no idea how he does it (he does say he’s using wireless energy transmission) so a few solution videos would be cool, [Henryk].
Altoids tins make great electronic enclosures, but how about designing your PCBs to fit mint and gum containers? Here’s a Trident USBASP, a tiny Tic Tac ISP thingy, and a Mentos USB to JTAG interface.
By the end of this week, the PS4 will be out, along with the new PS4 camera. It’s a great camera – 1280×800 at 60Hz – but unless someone develops a driver for it, it shall forever remain tethered to a PS4. Luckily, there’s a project to develop a PS4 camera driver, so if you have some USB 3.0 experience, give it a shot.
Multimeter teardowns? [David]’s got multimeter teardowns. It’s an HP 3455A, a huge bench top unit from the 80s. This is, or was, pro equipment and strange esoteric components definitely make a showing. ±0.01% resistors? Yep. Part two has some pics of the guts and a whole ton of logic.
The US Air Force Academy just moved their embedded systems course over to the MSP430. Course director [Capt Todd Branchflower] just put all the course materials online, with the notes, datasheets, and labs available on Github.
It’s pretty common to have at least a couple of meters around to measure different values of a circuit at the same time. Where [Emilio P.G. Ficara] ran into a problem was logging the data from both at once. These
Fluke meters have a serial-out, but his computer only has a single serial-in port. He cracked open one of the meters and figured out how to log data from both at the same time.
A lot of folks would look to a microcontroller to solve this problem. You use the chip to pull from each meter simultaneously and report back to a computer (or just dump the values onto an SD card). But this solution is a simple mechanical connector and a bit of creative programming. The way the serial output is set up on these meters they won’t interfere with each other as long as they’re read one at a time. [Emilio] wired them up as seen above, using his own software to manage the pins of the serial port. The example output he posted shows readings from the meters taken within about a tenth of second from each other. That should be good enough for most applications.
The old Fluke 8050a multimeter from the 80s is an awesome piece of lab equipment. It’s built like a tank, and thanks to the newer more portable models, this old meter is available for a pittance on eBay. [Ken] picked up a few of these meters and decided to give one of them a little upgrade – a 2.2″ 320×240 LCD display that is a vast improvement on the old stock seven-segment numerical display.
Inside the Fluke 8050a is a 40-pin DIP processor that handles all the computations inside the unit. [Ken]’s solution to tap into this processor was to take a 40-pin PIC microcontroller, bend some of the pins backwards, and use the remaining pins to drive the new LCD display. It’s actually somewhat brilliant in its simplicity and looks really cool to boot.
The rest of the circuitry consists of a level converter and a few wires going directly to the LCD display. [Ken] already has another Fluke 8050a on the bench waiting for a facelift and some plans for a few improvements that include a bar graph, histogram, and possibly even a touch display.
[Gnif] was doing what any good hacker does… poking around the insides of one of his tools to see how it works. While in there, he discovered that an EEPROM hack could make the Agilent U1241A function like the U1242A.
If you’re into this kind of thing the Rigol 1052e hack should have already popped to mind. That was a firmware crippled device that, when unlocked, made the cheaper model behave the same ways as it’s $400 more expensive sibling. This doesn’t have quite the same impact, as the price difference is somewhere between $20-$100. Still, this stuff is just cool, right?
A few posts down in the thread linked above [Gnif] shares the story of how he found the hack. After shorting the i2c lines of the EEPROM while powering up the meter he was able to see that the device initializes a lot of its values to 0xFF when it can’t find the stored data. The next step was to use an STM32 board to dump the EEPROM contents. With the backup file stored safely he started changing values and reflashing the chip. Through this process he discovered that switching one byte from 0x01 to 0x02 enabled the higher model’s features. It also works for upgrading the U1732C to the U1733C feature set.
[How To Lou] sure has shown us how to do quite a few things. This time he’s dealing with an electric clothes dryer that won’t heat. We’ve been elbow deep in our own appliances and we think [Lou’s] matter-of-fact demonstration will help you gain the confidence to investigate problems before deciding if it’s a job to be relegated to the repair man.
This picture shows the back side of a clothes dryer after having a protective panel removed. Just out of frame is a functional schematic which lists each part and it’s resistance measurement. Lou has labelled those parts in this image to help us understand what we’re looking at. In the video after the break he begins doing the same troubleshooting that a repair would use. He grabbed his multimeter and used it to test the resistance of each component after removing the wires from it. All of them should read zero Ohms except for the heater coil which the schematic rates at 7.8-11.8 Ohms. The high limit thermostat is loose and measures an infinite resistance. This, coupled with the charred wire on one side is the culprit. As with that ice maker repair from yesterday, [Lou] searches for the numbers on the part to find the replacement he needs.
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