Precision Pantograph Probes PCBs

October 4, 2017 by Brian McEvoy 26 Comments

Electronic components are getting smaller and for most of us, our eyesight is getting worse. When [Kurt] started using a microscope to get a better view of his work, he realized he needed another tool to give his hands the same kind of precision. That tool didn’t exist so he built it.

The PantoProbe is a pantograph mechanism meant to guide a probe for reaching the tiny pads of his SMT components. He reports that he has no longer has any trouble differentiating pins 0.5 mm apart which is the diameter of the graphite sticks in our favorite mechanical pencils.

[Kurt] has already expanded his machine’s capability to include a holder for a high-frequency probe and even pulleys for a pick-and-place variation. There’s no mention of dual-wielding PantoProbes as micro-helping-hands but the versatility we’ve seen suggests that it is only a matter of time.

Four bar linkages are capable of some incredible feats and they’re found all around us. Enjoy one of [Kurt]’s other custom PCBs in his Plexitube Owl Clock, or let him show you to make 3D objects with a laser engraver.

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Over-Engineered Mailbox Flag Machined Using Under-Engineered Mini-Lathe

October 3, 2017 by Anool Mahidharia 55 Comments

[Tim Nummy] used his cheap, Chinese, bench mini-lathe to make a non-terrible mailbox flag holder (YouTube video, embedded below). Tim posts videos on his channel about garage hobby projects, many of which are built using his mini-lathe, often based on suggestions from his followers. One such suggestion was to do something about his terrible mailbox flag – we’re guessing he receives a lot of old-school fan mail.

He starts off by planning the build around 1 ¼ inch aluminum bar stock, a 688 bearing, three neodymium magnets and some screws. The rest of it is a “think and plan as you go along” project, but essentially, the new holder is in three pieces. An inner piece goes inside the mail box and holds the assembly to the mail box. The middle piece holds the two magnets which act as end-stops or limits for the flags raised and lowered positions. The final, outer piece holds the flag itself, and the bearing which allows it to rotate freely.

This part also has the third magnet embedded in it to work with the other two magnets for the limits. The use of magnets is cool, but a ball catch with two detents would have worked just as well. It’s a great simple project to follow for those who want to wet their feet on lathe work. [Tim] has also posted links to all of the tools and equipment seen in the video, so check that out if anything catches your fancy.

But workshop veterans will almost certainly cringe at several places along the video. The main one that caught our eye is obviously the shaky lathe itself. It could do with a heavier workbench, proper leveling, foundation bolts or anti-vibration mounts. And from the looks of it, the tail stock isn’t any rock steady too. Although the lathe is variable speed, the chuck rpm is set too high for aluminum, and the lack of cutting fluid makes it even more troublesome. Using oil, or even some cutting fluid, while tapping would have been wise too.

We’re not sure if it’s the shaky foundation or poor feed control, but the step cut for mounting the bearing is over-sized by a whole lot more and requires a big goop of retaining compound to glue the bearing in place. But the end result works quite well, including the magnetic catches – a complex solution for a simple problem.

We’re sure our keen-eyed readers will likely spot some more issues in [Tim]’s methods, so go at it in the comments below, but please make sure to rein in the snark and keep your feedback positive.

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World’s Largest Telescope Stopped By LED

October 3, 2017 by Michael Uttmark 75 Comments

Earlier this year a simple indicator LED brought the Keck 1 telescope, a 370 tons mass, to a halting stop. How exactly did an LED do this? Simple: it did nothing.

As it so happens, [Andrew Cooper] was just about the leave the summit of Mauna Kea (in Hawaii) when his radio instructed him otherwise: there was an issue. Upon returning, [Andrew] was met by a room of scientists and summit supervisors. “Yeah, this was not good, why are they all looking at me? Oh, h%#*!” The rotor wasn’t moving the telescope, and “no rotator equals no science data.” After being briefed on the problem, [Andrew] got to work. Was it a mechanical issue? No: manual mode worked quite fine, also indicating that the amplifiers and limit switches are functional as well.

Jumping from chip to chip, [Andrew] came across an odd voltage: 9.36V. In the CMOS [Andrew] was investigating, this voltage should have High (15V) or Low (0v) and nowhere in between. Judging by the 9.36V [Andrew] decided to replace the driving IC. One DS3632 later, nothing had changed. Well, maybe is one of the loads pulling the line low? With only two choices, [Andrew] eliminated that possibility quickly. Likely feeling as if he was running out of proverbial rope, [Andrew] remembered something important: “the DS3236 driving this circuit is an open collector output, it needs a pull-up to go high.”

Reviewing the schematic, [Andrew] identified the DS3236’s pull-up: an LED and its current limiting resistor. While the carbon composition resistor was “armageddon proof,” [Andrew] was suspicious of the LED. “Nick, can you get me a 5k resistor from the lab?” Hold the resistor on the pins of the chip and the amplifiers immediately enabled.

[Andrew] summarizes things quite well: “yes… One of the world’s largest telescopes, 370 tons of steel and glass, was brought to a halt because of a bad indicator LED”. It stopped things by doing nothing, or rather, by not turning on.

We love it when we get troubleshooting stories, and if you share our interest in problem-solving, check out this broken power supply troubleshooting or learn what could go wrong with I2C.

Edit: Keck 1 is one of the largest optical telescopes in the world. Thanks to [Josh] for noticing our error.

Hacking A Metallurgical Microscope

October 1, 2017 by John Baichtal 10 Comments

[Amen] wanted to inspect ICs on the PCBs for suitability for reuse, so he bought a metallurgical microscope that illuminates from above rather than below, since it normally looks at opaque things. It has a working distance of 0.5 mm and 10 mm, which isn’t a lot of room to solder.

The microscope didn’t come with a slide tray, so [amen] found a cheap one on eBay. Needing a connector block, he melted down some food trays into an ingot, which he then milled down into a block shape, drilled, and used to attach the slide tray to the microscope.

The thing came with a manual XY table, which the operator adjusts by turning knobs. It’s fine for most basic applications but it’s also a pain for more complicated projects, like tiling together a huge photo of a die. [amen]’s currently working on a powered XY based on a DVD drive’s stepper assemblies.

If you’re looking for more microscope projects, read up on the hacked inspection microscope and a Pi Zero ‘scope we previously published.

Teletype Machine Resurrected

September 29, 2017 by Rich Hawkes 10 Comments

A teleprinter is, at its heart, an automatic typewriter. It’s electrically controlled and has some smarts to be able to decode an incoming message and has something that will move the keys. These printers have been in use since the late 1800’s and [AethericLtd] have refurbished an old 1930’s design and given it a bit of steampunk flair.

As is common with older mechanical devices that have been sitting for extended periods of time, the first thing this machine needed was a bath. The machine was separated into its three main parts and soaked in a degreasing solvent. The keyboard was the dirtiest, so it got an overnight soak. Since little of the mechanism was electrical, most of it could be submerged which helped with the cleaning.

The next step in the restoration was lubrication. In order to do a proper job, the manuals (which were available online) were consulted and synthetic motor oil used for lubrication. Once all the hundreds of parts were oiled, [AethericLtd] started working on the wiring. The original wiring in this machine was called Deltabeston – a type of wire by General Electric which uses asbestos insulation. To play it safe, that wire was left alone. The selector magnet required only 4 volts to pull up, but 4 volts wasn’t enough to run the machine. The power supply used was a 120 VDC, 200 mA supply through a 2 KΩ, 10 W resistor.

Once everything was back together and working, [AethericLtd] could take machine out and show it off. The website describes not only the restoration process but also the setup, how to connect to the machine and how to communicate with the machine. Great work! If you are interested in these machines, there have been a few Teleprinter projects on the site before: this one has been modified to connect to a modern modem, and this one prints out tweets.

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OLED Hacked Power Bank

September 29, 2017 by Pedro Umbelino 20 Comments

In a feat of over-engineering, [Everett Bradford] hacked his power bank to add power monitor via an OLED display to show live current, voltage, temperature, and capacity information. The idea came when he learned about the INA219 chip. The INA219 is a current shunt and power monitor IC with an I²C or SMBUS compatible interface. The device is able to monitor both shunt voltage drop and bus supply voltage, with programmable conversion times and filtering. A programmable calibration value, combined with an internal multiplier, enables direct readouts of current in amperes. An additional multiplying register calculates power in watts.

With impressive miniaturization skills, [Everett] dissembles the Xiaomi Mi power bank and manages to add a custom power monitoring module and an OLED display. Not only that, he replaced the 4 LEDs that were the battery level indicators and actually consume more amps than his board plus the display. While active, the board consumes about 8mA. In sleep mode, it consumes less than 30µA.

The 32×64 OLED display and the custom-made circuit was assembled and tightly fitted into the original case. The power bank now gives readings of the battery charge level in a small graph, numeric current input/output, voltage and temperature. The seamless integration of the display into the power bank makes it look like something that could perfectly have come from a store. This is not your typical DIY power bank nor a gigantic 64 cells power bank. It is a precise and careful modification of an existing product, adding value, functionality, and dare I say it, style: an awesome hack!

We can see [Everett] process in the following video:

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Mini Drill Made From A Motor

September 28, 2017 by John Baichtal 58 Comments

We love this hacked-together mini drill by [BuenaTec] that uses a DC7.2V 10K-RPM motor with a 1/8” Dremel chuck added on. Power is supplied by a USB-A cable with the data wires cut off, with a switch controlling the voltage and a rectifier diode protecting the USB port or battery pack from back voltage from the motor.

The drill isn’t very powerful, only able to bore holes in PCBs, plastic, and similar soft materials. However, you could see how just a couple more components could make it even more robust — maybe a speed controller and voltage booster? Even so, we appreciate this bare-bones, ultra-low budget approach — only the barest essentials are included, with the components held together with hot glue and solder. Also, no one is allowed to complain about their soldering iron after viewing this video.

For more projects involving motors, read up on this brushless motor made from 3D-printed parts and this guide to hand-winding quadcopter motors.