Lego Minifig multimeter makes resistor sorting a lot more fun


While there’s typically not much room on our work bench for toys, [David] over at Robot Room has put together a pretty cool multimeter for which we would make an exception.

His Lego Minifig multimeter is constructed using mostly standard off-the-shelf Legos, and a pair of Minifigs he modified to suit his needs. Translucent Minifig heads were sourced online to allow the neck-mounted LEDs to shine through, and each of the bodies were drilled out in several places to accommodate the wires he uses to take measurements.

The multimeter will display the resistance of any item from 10 – 10,000,000 Ω, as well as measure the voltage of any battery you can manage to fit under the Minifig’s metal wrench. The multimeter takes measurements using an ATmega168, and relays that data through a serial to USB converter connected to a nearby computer. The computer is host to a .NET application he wrote which displays and speaks both the resistance and voltage values.

Keep reading to see a quick video walkthrough and a demonstration of the multimeter at work.

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Make presents: The Multimeter

This video falls under the category of things we want to send people when they ask “how do I get started with electronics”, and we get asked that a lot. For those of you who have been working with electronics for years at all, you can skip this entire video. That is, unless you really want to watch an instructional video on multimeters. In the video, which we’ve included after the break, they talk about the differences between different meters, the common uses and how to actually use the meter to get the results you need. Stuffed full of useful information, this video will get those of you who are still reading up to snuff pretty quickly. Now go use your multimeter to do some hacking!

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Building a spectrophotometer

What can you make with a toilet paper roll, duct tape, and a graphing calculator? A stand for your homemade spectrometer. This is neither as pretty nor as accurate as a precision scientific instrument, but that doesn’t mean it’s useless. In fact, it works perfectly well for rudimentary observations. Light is shined through a sample solution, passes through a diffraction grating, then shows up as bands of color on the projection surface seen above. The photosensor mounted on the cardboard tube was pulled from a night-light, and is read using the ruler and the multimeter. This results in two data units that are used to graph the results. As long as you’re running test samples as a control this simple setup will yield useful information for the scientist on a shoe-string budget.

[via BoingBoing]

Unlocking RS232 serial comm on a multimeter

[Craig] cracked open a multimeter to unlock RS232 serial communications that can be used for data logging. There’s a couple of things that make this possible. First of all, the multimeter’s processor is not covered in a black epoxy blob, leaving the pins exposed for hacking. Second, the chip model is known and [Craig] was able to get his hands on the datasheet. One of the pins enables serial output when pulsed low. Touching it to V- even turns on an RS232 icon on the display, as seen above. To make this accessible without opening the case a momentary push button can be added, as well as connector for signal output, and a bit of parsing on the PC side to handle incoming data.

Multi Multimeter clock

[Alan Parekh] built this clock to look like a Multimeter using analog multimeters for the three displays. A PIC does the timekeeping and feeds a specific amperage to the three displays which show hours, minutes, and seconds.

We’ve seen clocks that use analog meters before. [Alan] took the concept to the next level, replacing the graduated markings behind each needle to correspond to the correct display. He’s also included precise calibration so that each meter is as accurate as possible. After watching his video we’re convinced this is a refined product ready for a wide market, at least for those who appreciate the geek factor of the display.


The Superprobe is a logic analyzer, multimeter, and much more rolled into a fun to build project. [Ben Ryves] didn’t come up with the original idea, but he definitely took a good thing and made it better. You can use it to test logic, inject logic into a circuit, read capacitors and resistors, test frequency, read the device address from 1-wire devices, and more. Interchangeable probes, choice of internal or external power, simple two-button operation, and a powerful PIC microcontroller at the heart of it all make this a fantastic tool for your electronics workbench. Check out the quality video after the break that  [Ben] put together to show off the results of his tinkering. [Read more...]

Hybrid analog/binary clock, the MK2

[Kieran] let us know about his hybrid analog/binary clock. The circuitry behind the clock is nothing too new. An Arduino combined with a Chronodot to produce an accurate clock. What we really enjoyed however was the creative implementation of an old British Telecom Linesman’s Multimeter as the case. The analog meter acts as the seconds hand, while a another display made of LEDs diffused with stripboard is the binary clock. The end product is nothing short of ingenuitive.