Breadboards Go To Pot

August 24, 2015 by Al Williams 7 Comments

Solderless breadboards are great for ICs and discrete components like resistors, capacitors, and transistors (at least the through hole kind). They aren’t so good at holding big components like potentiometers. Sure, you can jam trimmers in maybe. You can also solder leads to a pot, but that’s not pretty and tend to pull out when handled. [PaulStoffregen] got tired of it, so he put together some good looking PC boards that mount a 6mm shaft pot securely to a breadboard.

[Paul] noticed that having delicate or knobless adjustments on a breadboard inhibited people from playing with demo circuits. The new set up invites people to make adjustments. The pictures and video show an early version with six pins, but [Paul] added two more pins on the recent batch to increase the grip of the breadboard.

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Hot-Wire CNC Foam Cutter From E Waste

August 24, 2015 by Kevin Dady 3 Comments

A couple of old DVD ROM drives and a compact photo printer is fairly standard fare at the thrift store, but what do you do with them? Hack them up to make a CNC foam cutter of course!

[Jonah] started with a couple LITE-ON brand DVD RW drives, which use stepper motors instead of plain old DC motors. This is a huge score since steppers make accurate positioning possible. With the internal frames removed, threaded rod and nuts were used to hold the two units parallel to each other forming the Z axis.

The feed mechanism from a Canon compact photo printer was then bolted onto the bottom to form the Y axis. Add a bit of nichrome wire for the cutting element (this can be found in old hair dryers) onto where the laser assembly of the DVD rom once lived, and you have the mechanics done.

Control is handled by an Arduino and some easy-driver modules to interface with the steppers. G-Code is generated by CamBam, which handles various cad files, or has its own geometry editor.

This is a fantastic way to get your feet wet in several ways; Cracking things open to harvest parts, driving steppers with simple micocontrollers, modeling and generating g-code, etc. The one issue we see with this build is a chicken-or-egg problem since you need to have a cube of foam cut down to somewhat strict dimensions before it will fit in this cutter. But we suppose that is really just an iterative design problem.

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Building An Atomic Force Microscope On The Cheap!

August 22, 2015 by Nava Whiteford 13 Comments

LEGO2NANO, are building an open hardware AFM (Atomic Force Microscope).

AFMs are a kind of probe microscope. Unlike an optical microscope, a probe is used to “feel” the topology of a surface. An atomic force microscope uses a flexible cantilever with a nanometer scale tip on the end. As the tip scans across the surface it will be deflected by its interaction with the surface. A laser spot is usually reflected off the back of the cantilever, and captured by a photodiode array. The angle of the reflected beam, and therefore which photodiodes are excited lets you know how much the cantilever was deflected by the surface.

One of the challenges of building an AFM is developing an actuator that can move with nanoscale precision. We recently reported on [Dan Berard]s awesome capacitor actuator, and have previously reported on his STM build which uses a piezo buzzer. LEGO2NANO are experimenting with a number of different configurations, including using Piezo buzzers, but in a different configuration to [Dan]s system.

The LEGO2NANO project runs as a yearly summer school to encourage high school students to take part in the ambitious task of building an AFM for a few hundred dollars (commercial instruments cost about 100,000USD). While the project isn’t yet complete, whatever the outcome the students have clearly learned a lot, and gained an exciting insight into this cutting edge microscopy technique.

Monsieur Adaptateur: Jacques Of All Connector Trades

August 21, 2015 by Al Williams 16 Comments

It seems that any time you have a circuit on the bench, there’s wires. Lots of wires. If you are working on something new, it is a good bet that some of those wires are clipped to other wires using some field expedient, especially the power wires. We often have an alligator clip awkwardly grabbing the shell of a BNC. [Felicitus] got tired of this, so he created Monsieur Adaptateur, a breakout board that has common connectors you’ll need when working on a prototype.

What kind of connectors?

DC Jack 2.1mm
2mm Jacks
4mm Jacks
BNC Connector
Terminal Block
Scope probe connector
Standard 6 pin 0.1″ female header
Standard 6 pin 0.1″ male header
4.75 and 6.3mm blade connectors

The dual conductor items (like the 2.1mm jack and the BNC) connect to both sides of the board. The other connectors are in pairs. The idea is you can connect, for example, a BNC cable from a signal generator to some jumper wires on the male header, connect the scope to the scope probe connector, and still have the banana jacks to hook up, say, a digital meter.

No one would say this is going to change the world, but this is one of those things that is simple, but very useful. The plans are all on Github, and obviously you could adapt it with connectors that make sense for your specific situation.

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A Tale Of Two Browser PCB Tools

August 21, 2015 by Al Williams 51 Comments

We live in a golden age of free Electronic Design Automation (EDA) tools. It wasn’t that long ago that an engineering workstation was an expensive piece of hardware running very expensive software that typically had annual fees. Now, you can go to your local electronics store and buy a PC that would shame that old workstation and download plenty of software to design schematics, simulate circuits, program devices, and lay out PCBs.

The only problem with a lot of this free software is it runs on Windows. I do sometimes run Windows, but I most often use Linux, so there is a certain attractiveness to a new breed of tools that run in the Web browser. In particular, I wanted to look briefly at two Web-based EDA tools: EasyEDA and MeowCAD. Both offer similar features: draw a schematic, populate a PCB, and download manufacturing files (that is, Gerber files). EasyEDA also offers SPICE simulation.

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Tap On! Tap Off! The Backlight!

August 20, 2015 by George Graves 17 Comments

We recently covered [TechnologyCatalyst’s] excellent $50 multimeter shoot out, and we weren’t surprised when the winner was the Uni-T UT61E. It’s jam packed with features, and has a lot of bang for your buck. But one thing that it’s missing is a backlight.

The 61E uses a chip form CyrusTek called the ES51922A. This chip has a back light features built into it, but Uni-T simply didn’t add the supporting circuitry and LEDs. This was done either to keep cost down, or to not take away sales from their higher end models – your guess is as good as ours. Even though several people have tried carefully soldering to this fine pitch chip package to add back lights, the backlight timer is set to turn off in 60 seconds.

[Nisei] on the EEVBlog forum came up with an elegant capacitive touch solution that we could see being used in many other applications. The mod centers around a using a TTP223 touch sensor module that you can find on eBay for $1 instead of tapping into the meter’s dormant backlight controller. Add in a voltage regulator, a resistor, 2 leds and some foil tape, and that’s about all you need. [Nisei] did a great job documenting the mod with graphics rather than pictures (that can be a bit ambiguous at times.) Also, in case you missed the $50 DMM review you can find it here.

With all that said, we’re thinking the next multimeter mod might just need to be the “Clap-On, Clap-off” meter.

High Tech, Low Cost Digital Torque Meter

August 20, 2015 by Dan Maloney 40 Comments

Ever obsessed with stripping the hype from the reality of power tool marketing, and doing so on the cheap, [arduinoversusevil] has come up with a home-brew digital torque meter that does the job of commercial units costing hundreds of times as much.

For those of us used to [AvE]’s YouTube persona, his Instructables post can be a little confusing. No blue smoke is released, nothing is skookum or chowdered, and the weaknesses of specific brands of tools are not hilariously enumerated. For that treatment of this project, you’ll want to see the video after the break. Either way you choose, he shows us how a $6 load cell and a $10 amplifier can be used to accurately measure the torque of your favorite power driver with an Arduino. We’ve seen a few projects based on load cells, like this posture-correcting system, but most of them use the load cell to measure linear forces. [AvE]’s insight that a load cell doesn’t care whether it’s stretched or twisted is the key to making a torque meter that mere mortals can afford.

Looks like low-end load cells might not be up to measuring the output on your high-power pneumatic tools, at least not repeatedly, but they ought to hold up to most electric drivers just fine. And spoiler alert: the Milwaukee driver that [AvE] tested actually lived up to the marketing. Continue reading “High Tech, Low Cost Digital Torque Meter” →