标签: MULTIMETER

Anyone here who still remembers the Heathkit "Stackables"? These were presented with a blue plastic box and a white front panel in build-it-yourself kit form.   As I recall, the Ix-528x series included a multimeter, RF signal generator, audio signal generator, signal tracer, RLC bridge, and -- possibly (I can't remember for sure) -- a power supply. These were a family of low-cost basic test instruments for the electronics experimenter/hobbyist/repair person. Their notable claim to fame was that they were all built into the same plastic cabinet that featured molded feet that interlocked with a molded top ridge so they could be stacked vertically and stably on a benchtop, thus saving a lot of scarce and valuable real-estate.   Think for just a moment about this simple concept, and how it can similarly apply in your food pantry. Lately I've noticed two types of tin cans -- the older style that can be vertically stacked because their bottoms mate with the tops of the cans beneath them (e.g., Campbell's soup tins), and a newer style that was designed by some dimwit who did not think to include the stackability feature (e.g., Kroger-brand veggies). Try to stack these types and they come crashing down like a house of cards. No question as to the preferred type to make the best use of the limited horizontal space in a pantry.   Other than the intentional Heathkit stackable feature, most older styles of test equipment were not designed to be stackable. However, since they typically came in flat-topped cabinet enclosures, this was an inherent attribute. Even units from different manufactures could easily be stacked on a bench into a reasonably stable "tower of power" -- just look at any of illustrator Daniel Guidera's monthly EETimes caption contest cartoons for examples.   Then, along came the aesthetic enclosure designers hired by marketeering managers with no brains. Fancy curves and non-flat tops -- test equipment styling started looking more like sports cars than truly functional items. The result is that many of them can no longer be stacked.   Keeping this in mind, let's look at how some of these non-mating test equipment boxes can be made to fit together on a limited-space benchtop. Consider the DMM sitting on top of a power supply as shown below. The unfolded front tilt-flap of the DMM keeps it from sliding backwards off the tilted-upwards power supply, but it tends to slip forward and hide the power supply's display.     However, when the tilt-flap folded against the DMM bottom as shown below, it prevents the DMM feet from engaging the power supply and it slides off.     One solution is to forcibly remove the annoying tilt-flap from the DMM, thereby allowing its feet to hold it somewhat in place. But the serial number that is on the tilt-flap is no longer part of the DMM, which could raise some issues with the ISO-9000 calibration auditor.   Next, consider the frequency counter sitting on top of a function generator as shown below. The front lip of the frequency counter holds it from slipping off the function generator, but it does make the function generator's button labels hard to see.     Swapping these two devices round and placing the function generator on top of the frequency counter doesn't work; the function generator's tilt-riser holds it from slipping off, but hides the counter's digits.   Even identical equipment made by the same dimwit manufacturer who never considered stackability can be stacked with the aid of series-connected cable tie-wraps as shown below (don't use duct tape because it can cover up the ventilation holes). By the way, if you have to tie-wrap-stack two scopes together to make a 4-channel scope, you (or your corporate fiscal expenditure manager) might be a Redneck (with apologies to Jeff Foxworthy).     Note that these Atten brand "Scopes from Hell" have a couple of functional bugs (among many) that are clearly visible in the above photo. One of these bugs is fairly obvious -- the other is a little more hidden. Can you spot these bugs? If so, please post a comment below. Also, please offer any suggestions you have for stacking these types of devices on your benchtop.   Glen Chenier Engineer

Do you still remember the Heathkit "Stackables"? These were presented with a blue plastic box and a white front panel in build-it-yourself kit form.   As I recall, the Ix-528x series included a multimeter, RF signal generator, audio signal generator, signal tracer, RLC bridge, and -- possibly (I can't remember for sure) -- a power supply. These were a family of low-cost basic test instruments for the electronics experimenter/hobbyist/repair person. Their notable claim to fame was that they were all built into the same plastic cabinet that featured molded feet that interlocked with a molded top ridge so they could be stacked vertically and stably on a benchtop, thus saving a lot of scarce and valuable real-estate.   Think for just a moment about this simple concept, and how it can similarly apply in your food pantry. Lately I've noticed two types of tin cans -- the older style that can be vertically stacked because their bottoms mate with the tops of the cans beneath them (e.g., Campbell's soup tins), and a newer style that was designed by some dimwit who did not think to include the stackability feature (e.g., Kroger-brand veggies). Try to stack these types and they come crashing down like a house of cards. No question as to the preferred type to make the best use of the limited horizontal space in a pantry.   Other than the intentional Heathkit stackable feature, most older styles of test equipment were not designed to be stackable. However, since they typically came in flat-topped cabinet enclosures, this was an inherent attribute. Even units from different manufactures could easily be stacked on a bench into a reasonably stable "tower of power" -- just look at any of illustrator Daniel Guidera's monthly EETimes caption contest cartoons for examples.   Then, along came the aesthetic enclosure designers hired by marketeering managers with no brains. Fancy curves and non-flat tops -- test equipment styling started looking more like sports cars than truly functional items. The result is that many of them can no longer be stacked.   Keeping this in mind, let's look at how some of these non-mating test equipment boxes can be made to fit together on a limited-space benchtop. Consider the DMM sitting on top of a power supply as shown below. The unfolded front tilt-flap of the DMM keeps it from sliding backwards off the tilted-upwards power supply, but it tends to slip forward and hide the power supply's display.     However, when the tilt-flap folded against the DMM bottom as shown below, it prevents the DMM feet from engaging the power supply and it slides off.     One solution is to forcibly remove the annoying tilt-flap from the DMM, thereby allowing its feet to hold it somewhat in place. But the serial number that is on the tilt-flap is no longer part of the DMM, which could raise some issues with the ISO-9000 calibration auditor.   Next, consider the frequency counter sitting on top of a function generator as shown below. The front lip of the frequency counter holds it from slipping off the function generator, but it does make the function generator's button labels hard to see.     Swapping these two devices round and placing the function generator on top of the frequency counter doesn't work; the function generator's tilt-riser holds it from slipping off, but hides the counter's digits.   Even identical equipment made by the same dimwit manufacturer who never considered stackability can be stacked with the aid of series-connected cable tie-wraps as shown below (don't use duct tape because it can cover up the ventilation holes). By the way, if you have to tie-wrap-stack two scopes together to make a 4-channel scope, you (or your corporate fiscal expenditure manager) might be a Redneck (with apologies to Jeff Foxworthy).     Note that these Atten brand "Scopes from Hell" have a couple of functional bugs (among many) that are clearly visible in the above photo. One of these bugs is fairly obvious -- the other is a little more hidden. Can you spot these bugs? If so, please post a comment below. Also, please offer any suggestions you have for stacking these types of devices on your benchtop.   Glen Chenier Engineer

Mastro Gippo's friend, who is blind, had requested for his help in locating a multimeter that could speak. What Mastro found was that they were quite expensive. The only meter he located cost over $2,000. Being the kind of guy who builds things in his spare time, he decided he wasn't going to just accept that cost, he would build one instead . He knew he could find a relatively cheap multimeter with serial output. His idea was to read the serial output with an Arduino, then spit out the corresponding audio. Ideally, this would all be packaged in a nice little container for portability. Mastro was in luck. He found a small MP3 player that could charge over USB, had a built-in speaker, auxiliary input, and extra space in the case. He ripped open the MP3 player, crammed in his Arduino Pro Mini and SD card reader, and reassembled it. By using the Super Simple SDaudio Library, he was able to get the audio output he needed for the MP3 player. As you can see in the video, the entire setup seems to work quite well. I don't speak Italian, so I can't vouch for the enunciation of the spoken words, but it sounds loud enough, and the package isn't too cumbersome. Of course, after he was finished, he noticed that there are, in fact, several cheap speaking multimeters on the market. At this point, that has become somewhat irrelevant! Caleb Kraft, Chief Community Editor, EE Times

I am personally quite keen on SparkFun. I think it's a great company that really shines in the open-source arena. It does a lot of educational work and puts out really great products. When I saw this news item pop up on the SparkFun blog, I read it, but then needed to take a little while to digest and contemplate what was going on. It appears that SparkFun has lost an entire shipment of 2,000 multi-meters because the yellow case and dark face of the meter infringes on Fluke's trademark.   SparkFun's Generic Multimeter   My initial response, as a person who owned a small business for a while, was outrage. SparkFun was out $30,000 worth of product because an inspector deemed that it was yellow? That is insane. How can a company trademark yellow? What the heck is going on here? After a taking a little while to think, and doing a little more research, I found myself empathizing with Fluke as well. Compare the Fluke 17B below to the SparkFun multi-meter above. The similarity is hard to deny. Add on top of that the fact that SparkFun is now going public complaining about Fluke protecting its trademark, and it doesn't look great for SparkFun.   Fluke 17B Then again, in SparkFun's defence, how many designs for multi-meters can there possibly be? In the end I find that I can see the frustration from both sides, and ultimately I'm just happy not to have to be involved. So, what do you think of the situation? Should Fluke settle on a specific shade of yellow as Tiffany's did with Tiffany Blue, as SparkFun points out? Is the fact that the face is grey enough of a similarity to justify the confiscation? Let us know your thoughts. Caleb Kraft is Chief Community Editor at EE Times.