Behold The WT-220: A ‘Clever’ VT-220 Terminal

December 20, 2018 by Donald Papp 27 Comments

[John Whittington] failed to win a bid for an old VT-220 serial terminal on eBay, so he decided to make his own version and improve it along the way. The result is the Whitterm-220 (or WT-220) which has at its core a Raspberry Pi and is therefore capable of more than just acting as a ‘dumb’ serial terminal.

Rear of the WT-220 with paint-filled laser engraving and all necessary connectors.

The enclosure is made from stacked panels of laser-cut plywood with an acrylic plate on the back for labels and connectors, where [John] worked paint into the label engravings before peeling off the acrylic’s protective film. By applying paint after laser-engraving but before peeling off the film, it acts as a fill and really makes the text pop.

Near the front, one layer of clear acrylic among the plywood layers acts as a light guide and serves as a power indicator, also doing double duty as TX/RX activity lights. When power is on, that layer glows, serving as an attractive indicator that doesn’t interfere with looking at the screen. When data is sent or received, a simple buffer circuit tied to the serial lines lights up LEDs to show TX or RX activity, with the ability to enable or disable this functionality by toggling a GPIO pin. A video overview is embedded below, where you can see the unit in action.

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Young Entrepreneurs Learn What Really Goes Into Making A Product

December 15, 2018 by Donald Papp 7 Comments

Just to be clear, the primary goal of the Papas Inventeurs (Inventor Dads) was to have the kids make something, have fun, and learn. In that light, they enjoyed a huge success. Four children designed, made, and sold laser-cut napkin rings from a booth at the Ottawa Maker Faire as a fun learning process (English translation, original link in French.) [pepelepoisson] documented the entire thing from beginning to end with plenty of photos. Things started at proof of concept, then design brainstorming, prototyping, manufacture, booth design, and finally sales. While adults were involved, every step was done by the kids themselves.

It all began when the kids were taken to a local fab lab at the École Polytechnique and made some laser-cut napkin holders from plywood for personal use. Later, they decided to design, manufacture, and sell them at the Ottawa Maker Faire. Money for the plywood came from piggy banks, 23 different designs made the cut, and a total of 103 rings were made. A display board and signs made from reclaimed materials rounded out the whole set.

In the end, about 20% of people who visited and showed interest made a purchase, and 60 of the 103 pieces were sold for a profit of $126. Of course, the whole process also involved about 100 hours of combined work between the kids and parents and use of a laser cutter, so it’s not exactly a recipe for easy wealth. But it was an incredibly enriching experience, at least figuratively, for everyone involved.

Possibly the biggest takeaway was the way manufacturing involved much more than just pressing “GO” on a laser cutter. Some pieces needed sanding after laser cutting, and each piece got two coats of varnish. If you missed it, [Bob Baddeley] showed how labor, and not materials, ends up being the most expensive part of a product.

Video Shows Power Isn’t Everything In Laser Engraving

October 11, 2018 by Donald Papp 22 Comments

When it comes to power tools, generally speaking more watts is better. But as laser maestro [Martin Raynsford] shows, watts aren’t everything. He shares a brief video showing his older 100 W laser being handily outperformed by a newer 30 W machine. Shouldn’t the higher power laser be able to do the same job in less time? One might think so, but wattage isn’t everything. The 30 W laser engraves and cuts a wooden tile in just under half the time it takes the 100 W machine to do the same job, and with a nicer end result, to boot.

Why such a difference? Part of the answer to that question lies in that the newer machine has better motion control and can handle higher speeds, but the rest is due to the tubes themselves. The older 100 W machine uses a DC-excited (big glass water-cooled tube) CO2 laser, and the newer 30 W machine uses an RF-excited laser that looks a bit like a big metal heat sink instead of oversized lab glassware. Both tubes output what is essentially the same beam, but the RF tube is overall capable of a more refined, more stable, and more finely focused point than that of the glass tube. Since engraving uses only a small fraction of even the 30 W laser’s power, the finer control that the RF laser has over the low end of the power scale results in a much higher quality engraving.

Embedded below is a short video showing both machines engraving and cutting the same tile, side by side. You may wish to consider watching this one full screen, to better see the fine details.

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Tracktorino Shields You From Poor Interfaces

April 21, 2018 by Brian McEvoy 8 Comments

On-screen controls in a digital audio workstation expand the power of a DJ or musician, but they are not intuitive for everyone. The tactility of buttons, knobs, sliders and real-world controls feels nothing like using a mouse, trackpad, or even a touchscreen. Unfortunately, devices meant to put control into a DJs hands can be unavailable due to location or cost. [Gustavo Silveira] took charge of the situation so he could help other DJs and musicians take control of their workstations with a customized MIDI interface for Traktor DJ software.

MIDI is a widely used serial protocol which has evolved from a DIN connector to USB, and now it is also wireless. This means that the Traktorino is not locked to Traktor despite the namesake. On the Hackaday.io page, there’s even a list of other workstations it will work with, but since many workstations, all the good ones anyway, accept MIDI hardware like this, the real list is a lot longer.

The custom circuit board is actually a shield. Using an Arduino UNO, the current poster child of the Arduino world, opens up the accessibility for many people who don’t know specialized software. A vector drawing for a lasercut enclosure is also included. This means that even the labeling on the buttons are not locked into English language.

Here’s another project which combined laser cutting and MIDI to make some very clever buttons or turn your DIN MIDI connector into USB.

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Cat Plays The Silver Ball For Treats

February 8, 2018 by Kristina Panos 12 Comments

It’s pretty easy to train a dog to do things for treats. They’re eager to please. But a cat? Most cats have better things to do than learn tricks no matter how many treats are involved. But if you make an autonomous game out of learning a trick, they just might go for it.

That’s the idea behind Touchy Fishy, a pinball machine for cats. It’s the newest iteration of treat-dispensing machines that [Kim] made for his cat, MIDI. The previous version was shaped like a dog’s head with a joystick for a nose. MIDI was so adept at pulling the joystick toward herself that [Kim] decided to try a new design using a lever.

Humans like challenges, too, and [Kim] wanted to make something purely mechanical this time around. The final product is mostly springs and laser-cut acrylic. MIDI pulls the spring-loaded lever downward, launching a pinball upward in an arc. At the top of its trajectory is a spinner enclosed in a circle. When the pinball hits the spinner, it sweeps a treat toward an opening, and the treat falls down where MIDI can eat it. The best part? The spinner also returns the captive pinball to its starting point, so MIDI can play until [Kim] gets tired of dropping treats into the hole. Watch MIDI claw her way to the high score after the break.

Most of the cat-related projects we’ve seen were built to keep hungry cats from sitting on their owner’s chests at 3AM, demanding to be fed. Here’s one that goes a step further by putting the cat to work collecting wiffle balls which it uses to pay for small amounts of kibble.

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Problems That Plagued An Edible Marble Machine

November 18, 2017 by Donald Papp 12 Comments

Prolific creator [Martin Raynsford] recently created a plus-sized edible version of his laser-cut Marble Machine for a Cake International exhibit and competition; it seemed simple to do at first but had quite a few gotchas waiting, and required some clever problem-solving.

Gears are three layers, stacked and cemented with sugar glue, and coated with a hard edible shine.

The original idea was to assemble laser-cut gingerbread parts to make the machine. Gingerbread can be laser-cut quite well, and at first all seemed to be going perfectly well for [Martin]. However, after a few days the gingerbread was sagging badly. Fiddling with the recipe and the baking was to no avail, and it was clear [Martin] needed to find something other than gingerbread to work with. After experimenting, he settled on a modified sugar paste which kept its shape and dried hard enough to work with. (While appearing to stretch most people’s definition of “cake” past the breaking point, the category [Martin] entered in the competition allows it.) The parts were cut by hand using laser-cut wood parts as a guide, then finished in a food dehydrator overnight.

The next problem was how to create the large spiral which forms the main ramp. The answer was to laser-cut a custom support structure that supported the piece while it dried out, and doubled as a way to transport the piece safely. High stress points got extra layers cemented with sugar glue, and some parts were reinforced internally with strands of uncooked spaghetti. Everything was sealed with an edible shine, which [Martin] says acts as a kind of varnish for cakes. A video demonstration is embedded below. Continue reading “Problems That Plagued An Edible Marble Machine” →

Making The Best Plywood For Laser Cut Puzzles

October 22, 2017 by Donald Papp 19 Comments

Plywood laser-cuts fairly well but has drawbacks when used in serious production runs, as [Marie] explains in a blog post about a quest for the ultimate laser-cutting plywood. One of the things [Nervous System] makes and sells is generative jigsaw puzzles, and they shared their experience with the challenges in producing them. The biggest issue was the wood itself. They ended up getting a custom plywood made to fit their exact needs, a process that turned out neither as complex nor as unusual as it may sound.

An example of how a dense knot hidden in one of the plywood layers caused the laser to not cut all the way through.

Plywood is great because it’s readily available, but there are some drawbacks that cause problems when trying to do serious production of laser-cut plywood pieces. Laser cutting works best when the material being cut is consistent, but there can be areas of inconsistent density in plywood. If the laser encounters an unexpected knot somewhere in the wood, there is no way to slow down or to increase power to compensate. The result is a small area where the laser perhaps doesn’t quite make it through. A picture of an example from my workshop shows what this looks like.

When doing basic project work or prototyping, this kind of issue is inconvenient but usually some trimming and sanding will sort things out. When doing a production run for puzzles like [Nervous System] was doing, the issue is more serious:

A jigsaw puzzle with a large number of cuts in a relatively small area has a higher chance of running into any problem spots in the material. If they exist, the laser will probably encounter them.
Trouble spots in plywood can be on the inside layers, meaning they can’t be detected visually and are only discovered after they cause an incomplete cut.
Increasing laser power for the whole job is an incomplete solution, as excessive laser power tends to make the cuts uglier due to increased scorching and charring.
An inspection process becomes needed to check each puzzle piece for problems, which adds time and effort.
A puzzle that had even one piece that did not cut properly will probably be scrapped because rework is not practical. That material (and any time and money that went into getting the nice artwork onto it) becomes waste.

Plywood is great stuff and can look gorgeous, but [Marie] says they struggled with its issues for a long time and eventually realized they had gone as far as they could with off-the-shelf plywoods, even specialty ones. They knew exactly what they needed, and it was time for something custom-made to serve those specific needs.

Having your own plywood custom-made may sound a little extreme, but [Marie] assures us it’s not particularly difficult or unreasonable. They contacted a small manufacturer who specialized in custom aircraft plywoods and was able to provide their laser-cut plywood holy grail: a 3-ply sheet, with high quality basswood core with birch veneers, and a melamine-based glue. It cuts better than anything else they have used, and [Marie] says that after four years they had certainly tried just about everything.