Custom Jig Makes Short Work of Product Testing

When you build one-off projects for yourself, if it doesn’t work right the first time, it’s a nuisance. You go back to the bench, rework it, and move on with life. The equation changes considerably when you’re building things to sell to someone. Once you take money for your thing, you have to support it, and anything that goes out the door busted is money out of your pocket.

[Brian Lough] ran into this fact of life recently when the widget he sells on Tindie became popular enough that he landed an order for 100 units. Not willing to cut corners on testing but also not interested in spending days on the task, he built this automated test jig to handle the job for him. The widget in question is the “Power BLough-R”, a USB pass-through device that strips the 5-volt from the line while letting the data come through; it’s useful for preventing 3D-printers from being backfed when connected to Octoprint. The tester is very much a tactical build, with a Nano in a breakout board wired to a couple of USB connectors. When the widget is connected to the tester, a complete series of checks make sure that there are no wiring errors, and the results are logged to the serial console. [Brian] now has complete confidence that each unit works before going out the door, and what’s more, the tester shaved almost a minute off each manual test. Check in out in action in the video below.

We’ve featured quite a few of [Brian]’s projects before. You may remember his Tetris-themed YouTube subscriber counter, or his seven-segment shoelace display.

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This Creepy Skull Shows Time With Its Eyes

Sometimes you have an idea, and despite it not being the “right” time of year you put a creepy skull whose eyes tell the time and whose jaw clacks on the hour into a nice wooden box for your wife as a Christmas present. At least, if you’re reddit user [flyingalbatross1], you do!

The eyes are rotated using 360 degree servos, which makes rotating the eyes based on the time pretty easy. The servos are connected to rods that are epoxied to the spheres used as eyes. Some water slide iris decals are put on the eyes offset from center in order to point in the direction of the minutes/hours. An arduino with a real time clock module keeps track of the time and powers the servos.

Check out the video after the break:

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How To Time Drone Races Without Transponders

Drone racing is nifty as heck, and a need all races share is a way to track lap times. One way to do it is to use transponders attached to each racer, and use a receiver unit of some kind to clock them as they pass by. People have rolled their own transponder designs with some success, but the next step is ditching add-on transponders entirely, and that’s exactly what the Delta 5 Race Timer project does.

A sample Delta 5 Race Timer build (Source: ET Heli)

The open-sourced design has a clever approach. In drone racing, each aircraft is remotely piloted over a wireless video link. Since every drone in a race already requires a video transmitter and its own channel on which to broadcast, the idea is to use the video signal as the transponder. As a result, no external hardware needs to be added to the aircraft. The tradeoff is that using the video signal in this way is trickier than a purpose-made transponder, but the hardware to do it is economical, accessible, and the design is well documented on GitHub.

The hardware consists of RX508 RX5808 video receiver PCBs modified slightly to enable them to communicate over SPI. Each RX508 RX5808 is attached to its own Arduino, which takes care of low-level communications. The Arduinos are themselves connected to a Raspberry Pi over I2C, allowing the Pi high-level control over the receivers while it serves up a web-enabled user interface. As a bonus, the Pi can do much more than simply act as a fancy stopwatch. The races themselves can be entirely organized and run through the web interface. The system is useful enough that other projects using its framework have popped up, such as the RotorHazard project by [PropWashed] which uses the same hardware design.

While rolling one’s own transponders is a good solution for getting your race on, using the video transmission signal to avoid transponders entirely is super clever. The fact that it can be done with inexpensive, off the shelf hardware is just icing on the cake.

Pen Plotter From Salvaged Printer Parts

Like many of us, [Benjamin Poilve] was fascinated when he took apart a broken printer. He kept the parts, but unlike most of us, he did something with them, building a neat little plotter called the Liplo. Most pen plotters work by moving the pen on two axes, but [Benjamin] took a different approach, using the friction drive bars from the printer to move the paper on one axis, and a servo to move the pen on the other. He’s refined the design from its initial rough state to create a very refined final product that uses a combination of salvaged, 3D-printed, and CNC-milled parts.

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Badland Brawler Lets Arduino Tackle Terrain

For an electronics person, building the mechanics of a robot — especially a robust robot — can be somewhat daunting. [Jithin] started with an off-the-shelf 4 wheel drive chassis to build an off-road Arduino robot he calls the Badland Brawler. The kit was a bit over $100, but as you can see in the video below, it is pretty substantial, with an enclosed frame and large mud tires.

The remaining parts include an Arduino, a battery, and a motor driver IC. The Arduino is one with WiFi (an MKR 1000, in fact) and there’s a phone app for controlling the robot.

Honestly, once you have the chassis taken care of, the rest is pretty easy. Of course, the phone app is a bit more effort, but you could replace it in a number of ways. Blynk, comes to mind, for example.

The motor drivers are easy to figure out. This would be a great platform for some sensors to allow for more autonomy. We liked how the frame had mount points for a lot of different boards and sensors and could hold everything, for the most part, inside. That’s probably a good idea for a robot which will be traversing rugged terrain.

If you do decide to roll your own app with Blynk, we’ve done it with a very different kind of robot. Four-wheel drive robots don’t have to be big, as we’ve seen in the past.

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Arduino and the Other Kind of Homebrew

Usually, when we are talking about homebrew around here, we mean building your own equipment. However, most other people probably mean brewing beer, something that’s become increasingly popular as one goes from microbreweries to home kitchen breweries. People have been making beer for centuries so you can imagine it doesn’t take sophisticated equipment, but a little automation can go a long way to making it easier. When [LeapingLamb] made a batch using only a cooler, a stock pot, and a propane burner, he knew he had to do something better. That’s how Brew|LOGIC was born.

There are many ways to make beer, but Brew|LOGIC focuses on a single vessel process and [LeapingLamb] mentions that the system is akin to a sous vide cooker, keeping the contents of the pot at a specific temperature.

Honestly, though, we think he’s selling himself a bit short. The system has a remote application for control and is well-constructed. This isn’t just a temperature controller thrown into a pot. There’s also a pump for recirculation.

The common stock pot gets some serious modifications to hold the heating element and temperature probe. It also gets some spring-loaded clamps to hold the lid down. Expect to do a lot of drilling.

The electronics uses an Arduino, a Bluetooth board, and some relays (including a solid state relay). The finished system can brew between 5 and 15 gallons of beer at a time. While the system seems pretty good to us, he did list some ideas he has for future expansion, including valves, sensors for water level and specific gravity, and some software changes.

After reading that the system was similar to a sous vide cooker, we wondered if you could use a standard one. Turns out, you can. If you want to make better beer without electronic hacking, there’s always the genetic kind.

Sorter Uses Cardboard to Organize Card Hoard

If you collect trading cards of any kind, you know that storage quickly becomes an issue. Just ask [theguymasamato]. He used to be really into trading cards, and got back into it when his kids caught the bug. Now he’s sitting on 10,000+ cards that are largely unorganized except for a few that made it into sleeve pages.  They tried to go through them by hand, but only ended up frustrated and overwhelmed. Then he found out about [Michael Portera]’s Pi-powered LEGO card sorter and got all fired up to build a three-part system that feeds cards in one by one, scans them, and sorts them into one of 22 meticulously-constructed cardboard boxes.

[theguymasamato]’s card sorter is the last stop for a card after the feeder has fed it in from the pile and the scanner has scanned it. The sorter lazy Susans around on a thrust bearing, which is driven by a 3D printed drive wheel attached to a stepper. The stepper is controlled with an Arduino.

Here’s where it gets crazy: the drive wheel and timing belt are made from the flutes of corrugated cardboard. As in, he used that wavy bit in the middle as gear teeth. Every one of those cardboard teeth is fortified with wood glue, a time-consuming process he vows to never repeat. Instead, [theguymasamato] recommends using shims to shore them up as he did in the card feeder. The whole thing was originally going to be made from cardboard. It proved to be too mushy to support the thrust bearing, so [theguymasamato] switched to MDF.

Right now, the sorter is homed via button press, but future plans for the device include an IR break beam switch. We’re excited for the scanner and can’t wait to see the whole system put together. While [theguymasamato] works on that, position yourself past the break to watch the build video.

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