Syringes Put The Squeeze On This Mini Drill Press

July 5, 2020 by Tom Nardi 19 Comments

If you’re making your own PCBs for through-hole projects at home, getting the board etched is only half the battle; you’ve still got to drill all those little holes. It’s a tedious process, and if you’ve got a lot of them, doing them freehand with a drill just isn’t going to cut it. Which is why [Ruchir Chauhan] built this tiny 3D printed drill press.

This design is actually interesting for a number of reasons. The fact that it’s primarily 3D printed is a big one, though of course it’s not the first time we’ve seen that. We also like the minimal part count and low-cost, which is sure to appeal to those looking to produce PCBs on a budget. But the most impressive feature has to the hydraulic system [Ruchir] has come up with to actually do the drilling.

Rather than pulling an arm to lower the bit towards the work piece, a system utilizing four syringes, some water, and a bit of tubing is used to pull the tool down. This might seem extravagant, but if you’ve got a lot of holes to drill, this design is really going to save your arms. This method should also give you more consistent and accurate results, as you won’t be putting any torque on the structure as you would with a manually operated press.

[Ruchir] doesn’t offer much in the way of instructions on the project’s Hackaday.io page, but once you print out all of the provided STLs and get your syringes ready to go, the rest should be fairly self explanatory. Personally we might have added a smooth steel rod in there to make sure the movement is nice and straight, but we can see the appeal of doing it with a printed part to keep things cheap.

Looking for more ideas? If you’re after something a bit larger we might suggest this one made from PVC pipes, and this 3D printed desktop press would look good on anyone’s bench. Just don’t blame us if your arms get tired.

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AVR Multi-Tool Learns The Latest Tricks

July 2, 2020 by Tom Nardi 9 Comments

Like many of us who fiddle with microcontrollers, [Mike] and [Brian] often found themselves using an ISP programmer and a USB-to-serial adapter. But when they started working on the latest generation of ATtiny chips, they found themselves in need of a Unified Program, and Debug Interface (UPDI) programmer as well. So they decided to wrap all three functions into one handy open hardware gadget.

They call their creation the AVR General Purpose Programmer, or AVRgpp for short. It runs on an ATmega328P with a Pro Mini bootloader, which means that the programmer itself is fully compatible with the Arduino IDE. USB-to-serial capability is provided by a CH330N, and a MC14053 digital switch IC is used to select between talking to the AVRgpp’s onboard MCU or the target device.

A 128 x 32 I2C OLED and two push buttons are used to select the device’s current mode, and there’s a physical switch to select between 5 V or 3.3 V power for the target. There’s also a ST662 12 V regulator, as UPDI targets occasionally need a high voltage pulse to switch into programming mode. Everything is packaged up in a pocket-sized laser cut enclosure that you can easily toss in your bag.

[Mike] and [Brian] say they are considering putting the AVRgpp into small scale production if there’s enough interest, so let them know if you’d like to get one without having to build it yourself.

Build A Lathe Like It’s 1777

June 29, 2020 by Tom Nardi 22 Comments

We’ve seen quite a few scratch built lathes here at Hackaday, but none quite like the handcrafted pole lathe put together by [Jon Townsend] and his band of Merry Men as part of their effort to build a period-accurate 18th century log cabin homestead. With the exception of a few metal spikes here and there, everything is made out of lumber harvested from the forest around them.

The lathe is designed to be a permanent structure on the homestead, with two poles driven into the ground to serve as legs. Two rails, made of a split log, are then mounted between them. The movable components of the lathe, known as “puppets” in the parlance of the day, are cut so they fit tightly between the rails but can still be moved back and forth depending on the size of the work piece. With two metal spikes serving as a spindle, the log to be turned down is inserted between the puppets, and wedges are used to lock everything in place.

So that’s the easy part. But how do you spin it? The operator uses a foot pedal attached to a piece of rope that’s been wound around the log and attached to a slender pole cantilevered out over the lathe. By adjusting the length and angle of this pole, the user can set the amount of force it takes to depress the pedal. When the pedal is pushed down the log will spin one way, and when the pole pulls the pedal back up, it will spin the other.

Since the tools only cut in one direction, the user has to keep letting the pressure off when the log spins back around. The fact that the work piece isn’t continuously rotating in the same direction makes this very slow going, but of course, everything was just a bit slower back in the 18th century.

So now that we’ve seen lathes made from wood, intricately cut slabs of stone, and a grab bag of junkyard parts, there’s only one question left. Why do you still not have one?

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An Affordable Home Made Vacuum Chamber

June 29, 2020 by Jenny List 31 Comments

The term “vacuum” means many different things depending whether you are working on space equipment, scientific instruments, or even internal combustion engines. In our sphere it is so often used as a means to draw bubbles out of resin castings, for which it is a relatively easily achievable partial vacuum. It’s something [Fab] is using, in a vacuum chamber made from Plexiglass.

A simple Plexiglass box would collapse under the air pressure on its own, so to mitigate that it’s made from a piece of tube, and with an internal frame of aluminium extrusion with 3D printed joints to strengthen it from the inside. A pressure sensor allows regulation of the pump that drives the vacuum, and connections are made to the chamber using pneumatic hose connectors. It’s not immediately clear how it is sealed, whether there are nay gaskets or other sealant, or whether air pressure pushing the parts together provides enough of a seal.

We’ve featured a lot of vacuum chambers made for this purpose over the years, and we’d be interested to know what vacuum pump is being used here. If you’re curious too and want to build your own, perhaps you could try a fridge compressor.

Hantek 3-in-1 Instrument Reviewed

June 28, 2020 by Al Williams 22 Comments

What kid doesn’t want a Swiss Army knife? Maybe that was the idea behind Hantek’s 3-in-1 instrument that [Rui Santos] reviewed in a recent blog post. You can also watch the video version, below. The instrument is a combination oscilloscope, multimeter, and signal generator. The device is pretty inexpensive and comes in 40 MHz and 70 MHz versions. You can also get versions that drop the function generator if you want to save a little bit more.

The multimeter does 4000 counts and has the usual scales along with capacitance measurements. Rechargeable batteries make it portable, and the signal generator is capable up to 25 MHz. The scope is dual channel, but the sampling drops in half (125 megasamples per second) when using both channels.

The 2.8 inch color screen isn’t as big as your bench scope, but it’s good for a portable device. The review also mentions that there are few buttons so many operations require a lot of menu navigation, but — again — that’s a function of being small. Overall, [Rui] seemed to like the meter well enough. We’ve spent more on a good digital meter, so if this can do that function plus also give you a reasonable scope and signal generator, it seems like a fair deal.

This reminded us of a very polished version of the EM125 we took a look at a few years ago, although that didn’t have a color screen, a second channel, or a signal generator. Of course, signal generators are cheap enough if you want to keep it separate.

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Hinge Brings New Meaning To Flexible PCB

June 26, 2020 by Al Williams 9 Comments

It is not a secret that flexible PC boards can bend. But despite the substrate’s flexibility, you can’t really fold them completely over. That bothered [Carl] so he developed a hinge design so that he can fold a board completely in half. You can watch a video showing an example, FlexBox, below.

Normal boards can fold over, but the copper traces can’t tolerate a very tight bend radius. [Carl’s] trick is to make the folding part have no traces at all. Only a small bridge carries traces between the two halves and it is allowed to bend almost like an interconnecting cable.

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3D-Printed Tools Make Circuit Sculpture A Little Easier

June 24, 2020 by Dan Maloney 7 Comments

Having the tools needed to do a job is a powerful thing. Having the tools needed to make more tools for doing cool things is even better, though, and that’s where [Jiří Praus] took things with this 3D-printed jig for making his blooming tulip circuit sculpture.

If you haven’t seen [Jiří]’s tulip, check out our coverage from back when he first built it. The brass wire and tube mechanism and some clever linkages let a single servo open the Neopixel-adorned petals at a touch. But what started as a one-off romantic gesture for his wife on Valentine’s Day became something more, and what was a labor of love turned into just labor very quickly. [Jiří]’s solution, explained in the brief video below, is a 3D-printed jig that holds all the wires that form the tulip petals locked into position. The wire that defines the spine of the petal goes into a groove and gets held down with removable clips. The edge wires are held by rotating clips, and the veins of the petals just lay in place in grooves. The area around each joint is hollowed out so [Jiří] can solder easily without melting the plastic jig.

The best part comes at the end, when it’s time to release the completed petal. For that, a tool with pins that looks a little like a hedgehog is inserted from below, and pins that fit into each joint’s hole pop the finished petal off. We can see how this tool would greatly increase the production of his tulips, so if that’s his goal, he’s on track.

If you’re into circuit sculpture, you’re in the right place. Check out [Mohit Bhoite]’s Supercon talk on the subject, or some more of the tools [Jiří] has come up with to improve his art.

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