Dirt Cheap Motor Balancing And Vibration Analysis

March 7, 2015 by Kristina Panos 7 Comments

Ever the enterprising hacker and discerning tool aficionado, [Chris] knows the importance of “feel”. As a general rule, cheap tools will shake in your hand because the motors are not well-balanced. He wanted a way to quantify said feel on the cheap, and made a video describing how he was able to determine the damping of a drill using a few items most people have lying around: an earbud, a neodymium magnet, scrap steel, and Audacity.

He’s affixed the body of the drill to a cantilevered piece of scrap steel secured in a vise. The neodymium magnet stuck to the steel interrupts the magnetic field in the earbud, which is held in place with a third hand tool. [Chris] taped the drill’s trigger down and controls its speed a variac. First, [Chris] finds the natural frequency of the system using Audacity’s plot spectrum, and then gets the drill to run at the same speed to induce wobbling at different nodes. As he explains, one need not even use software to show the vibration nodes—a laser attached to the system and aimed at a phosphorescent target will plot the sine wave.

Just for fun, he severely unbalances the drill to find the frequencies at which the system will shake itself apart. Check it out after the break.

Continue reading “Dirt Cheap Motor Balancing And Vibration Analysis” →

A Functional Sonic Screw Driver (Well, Kind Of)

March 6, 2015 by James Hobson 14 Comments

[Jerome Kelty] just finished building this awesome data-logging Sonic Screwdriver with his 6-year-old son [Sam]. The Halloween previous, [Jerome’s] older son had dressed up as the Doctor, which had inspired [Sam] to make his own Sonic Screwdriver — however he declared that his screwdriver needed to actually work!

They sat down together and decided what it needed to be able to do. [Sam] has a pair of hermit crabs, so they thought it would be handy to be able to measure the temperature and the humidity of their habitat. It needed a flashlight for obvious 6-year old reasons, and it had to make the right sound effect when you used it too!

[Jerome’s] first thought was to 3D print it, but was met with a resounding no: “It needs to be metal!”

So out came the sketchpad and they started designing it to be cut on the lathe, using a combination of aluminum, brass and wood.

Many weekends later [Sam] and his dad finished the body of the screwdriver and started work on the electronics. To keep it simple they used an Arduino Pro Mini 5V with a Sparkfun OpenLog to record all the data — and a handful of sensors of course!

After modifying the body a few times they finally got all the electronic guts to fit inside the screw driver. It features an SD card you can remove to see the OpenLog data, but as a “cool factor” [Jerome] also programmed in the temperature sensor to output to the RGB LED, so little [Sam] can point at things to determine how warm or cold they are.

Continue reading “A Functional Sonic Screw Driver (Well, Kind Of)” →

DIY Thermal Insert Press

March 6, 2015 by Ethan Zonca 38 Comments

You might not know what a threaded insert is, but chances are you’ve seen one before. Threaded inserts are small metal (typically brass) inserts that are pressed into plastic to give a strong point of attachment for bolts and screws. These inserts are a huge step up from screwing or bolting directly into tapped plastic holes since the brass threads are very strong compared to the plastic. The only major downside to these inserts is that the press to install them is incredibly expensive. Thankfully, [Alex Rich] came up with a cheap solution: a modified soldering iron mounted to an Arbor press.

Commercial threaded insert presses typically use ultrasonic welding or heat welding to fuse inserts with plastic. [Alex] chose the simple route and went with heat welding, which (as you might imagine) is way simpler than ultrasonic welding. To provide the heat, [Alex] mounted a 100W Weller soldering iron to the press, which he says handles the impact with no problem. Unfortunately the copper tips of the Weller just wouldn’t hold up to the impact, so [Alex] made his own tips out of some brass he turned on a lathe.

If, like most people, you don’t have the capability of making injection-molded cases, let alone an Arbor press on hand, you’re not out of luck! Using this same technique people have successfully added thermal inserts to 3d-printed parts using a soldering iron and much smaller DIY presses. Have any ideas on how you could use thermal inserts in your 3d prints? Let us know in the comments.

Introducing The Solder Sucker 9000

March 3, 2015 by James Hobson 73 Comments

Using a regular plunger style solder sucker is tedious at best, and usually not that effective. If you’re trying to salvage components off a PCB, sometimes it can take longer than it’s worth to do — short of reflowing the entire board that is! But what if you had something to desolder individual components faster?

After getting fed up with his cheap plunger-based solder sucker, [electro1622] decided to try a different tactic. He reuses components from old PCBs all the time, so he tried something a bit unorthodox to remove them. Compressed air.

Now let’s just preface this with it will be messy, so you might want to set up a box to catch the removed solder. Simply use your iron of choice to heat up the solder globs holding back your components, and then blast it with compressed air out of a small nozzle. Way faster than a solder sucker.

Continue reading “Introducing The Solder Sucker 9000” →

Adam Savage’s First Order Of Retrievability Tool Boxes

February 28, 2015 by George Graves 28 Comments

Let’s face it, we’re all a bit obsessed with tools. Whether it’s an oscilloscope or a screwdriver, having just the right tool can be the difference between loving what you are doing, or dreading it. But oddly enough, not much is talked about tool organization. We tend to think that how you organize your tools is just as import as the tools themselves.

[Adam Savage] of Mythbusters fame might just be the king of tool organization. In this thread on the Replica Props Forum, [Adam] shares the design and construction of two sets of mobile tool boxes he built while working at Industrial Light and Magic. The idea is simple: First Order Retrievability. That is, you should never have to move one tool to get to another. That in turn affords the fastest, most efficient way of working.

The evolution of this idea started with medical bags (the kind doctors would use, back in the day when doctors still made house calls), but as [Adam’s] tool collection grew, the leather was no match for 50 pounds of tools. So, he stepped up to two aluminum tool boxes. Adding wheels and a scissor lift allowed for a moveable set, at just the right height, that are always in reach. Perfect for model making, where being able to move to different parts of a model, and taking your tools with you is key. If you’re looking for a list of what’s inside [Adam]’s box of wonder, here you go.

What are some of your favorite ways of organizing your tools? What tips or tricks do you have? Post a picture or description in the comments. I’m sure we all could learn a bit from one another.

DIY Through Hole Plating Like A Boss

February 25, 2015 by George Graves 67 Comments

We’ve seen plenty of professional looking, homemade PCBs over the years. But this is the first time we’ve seen such professional vias and through hole plating. Don’t let the green solder mask fool you. This is a homemade PCB.

[Kurt Skauen] started with your standard artwork, followed by etching. He then applied a solder mask that is UV curable. At this point, it’s nothing we haven’t seen done before. After drilling he then adds vias with wire. Again, we’ve seen that before as well. Where it gets interesting is his use of through hole plating rivets. We’ve heard of these micro-sized rivets in the past, but hadn’t seen their use documented as well as [Kurt] has.

Making such a professional looking board at home is practically an art form. One could argue that with today’s cheap, short run PCB fab houses, why bother with trying to do it yourself? Well, perhaps you need a professional looking board to show a client ASAP. Maybe you just hate waiting for your boards to arrive. Or maybe you do it just because you can. Either way, the results [Kurt] achieved are very impressive.

TwinTeeth: The Delta Bot PCB Factory

February 23, 2015 by Brian Benchoff 29 Comments

There are a few all-in-one CNC/milling/plotting/3D printing/engraving bots out there that claim to be mini factories for hobbyists, prototypers, and other homebrew creators. The latest is Diyouware’s TwinTeeth, a bot obviously inspired by a few 3D printers, but something that has a few interesting features we hope will propagate through the open hardware ecosystem.

The design of the TwinTeeth is an inverse delta bot, kinematically similar to a large number of 3D printers out there. Instead of suspending the tool from a trio of arms, the TwinTeeth puts the work surface on the arms and suspends the tool from the top of the machine. There are a few neat bonuses for this setup – all the tools, from a BluRay laser diode, a Dremel, solder paste dispenser, and a plastic extruder for 3D printing can be mounted in easy to mount adapters. The TwinTooth design uses three locking pins to keep each toolhead in place, and after a little bit of software setup this machine can quickly switch between its various functions.

One very interesting feature of this bot is the ability to mask off PCBs for chemical etching with a BluRay laser diode. This actually works pretty well, as evidenced by the teams earlier work with a purpose-built PCB masker machine. The only problem with this technique is that presensitized boards must be used. If that’s an issue, no problem, just use the Dremel attachment with a v-bit cutter.