Digital Caliper Sacrificed For DRO Project

DIY Lathe DRO

In general, machining metal on a lathe or mill takes skill and patience as the accuracy of the cuts are important. To make those accurate cuts, it is important to know where the tool is located and how far it moves. For manual machines, the most basic method of determining position is by using graduated dials mounted on the hand cranks. Although these graduated dials can certainly be accurate, they may be difficult to see and they also require the operator to do math in their head on the fly with every full revolution of the dial. Another option would be a digital read out (DRO) which has an encoder mounted to the moving axes of the machine. This setup displays the exact position of the tool on an easy to read numeric display.

Professional DRO kits for mills and lathes can cost between a few hundred dollars to several thousand dollars.  [Robert] has a lathe, wanted a DRO but didn’t want to shell out serious cash to get it. He built his own for super cheap in an extremely resourceful way…. using a Harbor Freight Digital Caliper. A housing was first fabricated so that the added equipment would not hinder the axis travel of the lathe. The caliper was then cut to length, installed in the housing and the entire assembly was then mounted to the lathe.

DIY Lathe DROIt is totally reasonable to use the stock caliper display to read the positional information, however, even these cheap digital calipers have connections for the encoder output data, which can easily be read by a microcontroller. That means it is super simple to hook these low-cost digital calipers up to a display remotely located in a more convenient position.

 

Pick and Place Machines at Maker Faire

A few years ago, every booth at a Maker Faire had a 3D printer. It didn’t matter if 3D printing was only tangental to the business, or even if the printer worked. 3D printers have finally jumped the shark, and there’s going to be an awesome t-shirt to reflect this fact. This year there weren’t many 3D printers, leaving us asking ourselves what the new hotness is.

Pick and place machines. We couldn’t find many at the faire, and only Carbide Labs’ Pick and Paste machine was working on picking up small resistors and LEDs the entire faire. Carbide’s Pick and Paste machine is exactly what you would expect in a pick and place machine: it picks up components out of tapes and wells, orients them correctly, and plops them down on a board.

The killer feature for the Pick and Paste is its modular design. The toolhead is expandable, allowing anyone to add a second vacuum nozzle to double the rate parts are placed, or a solder paste dispenser. The guys didn’t have the paste dispenser working for the fair (leaded solder and kids don’t mix), but this machine is effectively a combination pick and place machine and solder paste dispenser, something that’s usually two machines on an assembly line.

Also at the faire was Tempo Automation. They’re in a pseudo-stealth mode right now, waiting until everything works perfectly until bringing their machine to the masses. It is, however, exceptionally fast and about a third of the price of a similar machine.

The only other pick and place machine at the faire was the Firepick Delta, one of the more popular projects on hackaday.io and one of fifty finalists for the Hackaday Prize. Unfortunately, the FirePick Delta was broken in shipping, and although [Neil] was sitting right next to the 3D printing guys, it would have taken all weekend to repair the machine.

CircuitMaker from Altium

Altium recently announced CircuitMaker, their entry into the free/low-cost PCB design tool market. They’re entering a big industry, with the likes of Eagle, KiCad, gEDA, and a host of other tool suites. We had a few minutes to talk with Max in the Altium booth at World Maker Faire, and even got a bit of time with the tool itself.

Hands on, it definitely has the look and feel of Altium Designer, right down to the familiar yellow and green boxes for schematic and sheet parts. Center stage was the 3D view, a feature which Altium has had in their software since the late 90’s.

CircuitMaker’s website is pushing the collaboration aspect of the software. Design choices can be reviewed and commented on in real-time. This also suggests that the data files will live in Altium’s own cloud storage system.

CircuitMaker is still in the pre-beta phase, but they’re looking for beta testers now, so head over to the site and sign up!

Making an Inductor Saturation Current Tester

inductor saturation tester

[Kalle] tipped us about a quick project he made over a couple of evenings: an inductor saturation current tester. All the components used for it were salvaged from a beefy telecom power supply, which allows the tester to run currents up to 100A during 30us in the inductors to be characterized.

Knowing the limits of an inductor is very convenient when designing Switch Mode Power Supplies (SMPS) as an inadequate choice may result in very poor performances under high loads. [Kalle]‘s tester simply consists in a N-Mosfet switching power through a load while a shunt allows current measurements. The saturation point is then found when the current going through the inductor suddenly peaks. As you can see from the picture above, 16 4700uF electrolytic caps are used to compensate for the sudden voltage drop when the Mosfet is activated. A video of the system in action is embedded after the break.

[Read more...]

A Folding Laser Cutter

Want a laser cutter, but don’t have the space for one? How about a portable machine to engrave and cut wood and plastics? A folding laser cutter solves these problems, and that’s exactly what Red Ant Lasers was showing off last weekend at Maker Faire.

Inside the team’s Origami laser cutter is a 40 Watt CO2 tube, shooting its beam along an entirely enclosed beam path. The beam travels through the body of the machine, out into the folding arm of the machine, and down to whatever material you’ve placed the Origami on. It’s a 40 Watt laser so it will cut plywood and plastics, and as shown in the video above, does a fine job at engraving plywood.

This is a Class 4 laser device operating without any safety glass, but from the short time I spent with the Red Ant team, this is a reasonably safe device. You will need safety glasses if you’re within five feet, but after that, everything (according to OSHA, I think) is safe and not dangerous. Either way, it’s a tool just like a table saw. You don’t see commentors on the Internet complaining about how a spinning metal blade is dangerous all the time, do you?

The Red Ant guys are currently running a Kickstarter for their project, with a complete unit going for $4200. It’s pricier than a lot of other lasers, but not being constrained by the size of a laser cutters enclosure does open up a few interesting possibilities. You could conceivably cut a 4×8 sheet of plywood with this thing, and exceptionally large engravings start looking easy when you have a portable laser cutter.

Cryogenic Machining: Custom Rubber Parts

Cryogenic Machining Custom Rubber Parts

Fashioning a custom, one-off rubber part for your project isn’t usually an option, but [Ben Krasnow] has an alternative to injection molding and casting: machining frozen rubber.

As [Ben] points out, you can’t exactly pop a sheet of rubber on your mill and CNC the needed shape; the bit will push the material around rather than cut it. Freezing the rubber first, however, allows you to carve into the now-hardened material.

His initial setup consisted of a sheet of aluminum with water drizzled on top, a square of neoprene placed on the water, and a steady stream of -60 to -80C alcohol flowing directly onto the rubber. The water underneath freezes, holding the neoprene in place. This proved problematic as the ice-clamp gives way before the milling is complete. [Ben] later adds some bolts to clamp the pieces down, allowing the milling process finish as planned.

A small plastic tray sits underneath this assembly to capture the alcohol as it runs off, feeding it back with some tubing. [Ben] recommends against a submersible aquarium pump—his initial choice—because the pump stopped working after a few minutes immersed in the chilly alcohol. An external, magnetically-driven pump solved the problem although it does require manual priming.

Stick around after the jump for the video and check out some of [Ben's] other projects, like his quest for the perfect cookie, or CT scanning a turkey.

[Read more...]

Low Cost Lab Frequency Reference

The internals of a home built 10 MHz frequency reference.

[Mark] wanted an accurate frequency reference for his electronics lab. He specified some requirements for the project, including portability, ability to work inside a building, and low cost. That ruled out GPS, cesium standard clocks, rubidium standard clocks, and left him looking for a low cost Oven Controlled Crystal Oscillator (OCXO).

The Low Cost 10 MHz Frequency Reference is based around a Morion OCXO. These Russian oscillators are available from eBay second hand at about $40 a pop. With a stability well within the requirements, [Mark] order a few.

The next step was to stick all the components in a box. The two OCXOs in the box need about 3 amps to heat up, which is provided by a 12 V PSU. For portability, a sealed lead acid battery was added. The front panel shows the supply voltages, switches between mains and battery supplies, and provides connectivity to the OCXOs.

Since OCXOs work by heating a crystal to a specific temperature, they can use quite a bit of power in the heating element. To increase battery life, a neoprene foam insulator was wrapped around the OCXOs.

For less than $100, this portable tool will aid in calibrating equipment or creating very accurate clocks.

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