Sentry Water Gun Relies On LIDAR

June 24, 2020 by Lewin Day 5 Comments

As we head into summer, Super Soakers and their ilk become de rigeur ways to cool off in the heat. Not content with chasing targets himself, [Marcel] instead built a sentry water gun to do his bidding.

The build is one that leverages typical 3D printer components to get the job done. A Minitronics 2.0 board is used to run the show, packing a 40 MHz SAMD21 microcontroller for plenty of grunt. It’s Arduino compatible too, making it easy to program. It’s combined with NEMA17 and NEMA23 steppers and an external driver board to slew the gun towards a target. Target detection is via a RPLIDAR A1, which detects the range of nearby objects. This data is used to calculate the pan angle and tilt required to hit the target with a stream of water, fired by a relay-controlled solenoid.

It’s a fun build that does a good job of soaking those playing by the pool. [Marcel] aims to do further work to improve performance by reducing backlash and increasing slew speed. Sentry guns are a forever popular build around these parts. Video after the break.

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What’s The Deal With Snap Packages?

June 24, 2020 by Tom Nardi 151 Comments

Who would have thought that software packaging software would cause such a hubbub? But such is the case with snap. Developed by Canonical as a faster and easier way to get the latest versions of software installed on Ubuntu systems, the software has ended up starting a fiery debate in the larger Linux community. For the more casual user, snap is just a way to get the software they want as quickly as possible. But for users concerned with the ideology of free and open source software, it’s seen a dangerous step towards the types of proprietary “walled gardens” that may have drove them to Linux in the first place.

Perhaps the most vocal opponent of snap, and certainly the one that’s got the most media attention, is Linux Mint. In a June 1st post on the distribution’s official blog, Mint founder Clement Lefebvre made it very clear that the Ubuntu spin-off does not approve of the new package format and wouldn’t include it on base installs. Further, he announced that Mint 20 would actively block users from installing the snap framework through the package manager. It can still be installed manually, but this move is seen as a way to prevent it from being added to the system without the user’s explicit consent.

The short version of Clement’s complaint is that the snap packager installs from a proprietary Canonical-specific source. If you want to distribute snaps, you have to set up an account with Canonical and host it there. While the underlying software is still open source, the snap packager breaks with long tradition of having the distribution of the software also being open and free. This undoubtedly makes the install simple for naive users, and easier to maintain for Canonical maintainers, but it also takes away freedom of choice and diversity of package sources.

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Tracked Robot Makes Sand Drawings

June 24, 2020 by Al Williams 6 Comments

[Ivan] seems to enjoy making 3D printed vehicles with tracks. His latest one uses 50 servo motors to draw patterns in the sand at the beach. You can see it work in the video below. Well, more accurately you can see it not work and then work as the first iteration didn’t go exactly as planned.

An Arduino Mega 2560 provides the brains and the whole unit weighs in at almost 31 pounds, including the batteries. We didn’t see Ivan’s design files, although it wouldn’t be hard to do your own take on the robot.

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Netbooks: The Next Generation — Chromebooks

June 24, 2020 by Jonathan Bennett 35 Comments

Netbooks are dead, long live the Chromebook. Lewin Day wrote up a proper trip down Netbook Nostalgia Lane earlier this month. That’s required reading, go check it out and come back. You’re back? Good. Today I’m making the case that the Chromebook is the rightful heir to the netbook crown, and to realize its potential I’ll show you how to wring every bit of Linuxy goodness out of your Chromebook.

I too was a netbook connoisseur, starting with an Asus Eee 901 way back in 2009. Since then, I’ve also been the proud owner of an Eee PC 1215B, which still sees occasional use. Only recently did I finally bite the bullet and replace it with an AMD based Dell laptop for work.

For the longest time, I’ve been intrigued by a good friend who went the Chromebook route. He uses a Samsung Chromebook Plus, and is constantly using it to SSH into his development machines. After reading Lewin’s article, I got the netbook bug again, and decided to see if a Chromebook would fill the niche. I ended up with the Acer Chromebook Tab 10, codename Scarlet. The price was right, and the tablet form factor is perfect for referencing PDFs.

Two Asus Netbooks and a ChromeOS tablet. — Behold, my netbook credentials.

The default ChromeOS experience isn’t terrible. You have the functionality of desktop Chrome, as well as the ability to run virtually any Android app. It’s a good start, but hardly the hacker’s playground that a Linux netbook once was. But we can still get our Linux on with this hardware. There are three separate approaches to making a Chromebook your own virtual hackspace: Crostini, Crouton, and full OS replacement.

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How To Retrofit A Pick And Place Machine For OpenPnP, In Detail

June 24, 2020 by Donald Papp 9 Comments

[Erich Styger] owns a Charmhigh CHM-T36VA pick and place machine, which he describes as well-built and a great value of hardware for the money. However, the software end is less impressive, with a proprietary controller that is functional but not great. The good news is that it is possible to retrofit the machine to use the OpenPnP framework, which is open-source and offers more features. Even better, [Erich] has already done and documented all the hard parts!

The CHM-T36VA has two heads, vision system, and uses drag feeders.

The conversion requires upgrading a few hardware parts such as the cameras, replacing the controller’s firmware, then installing and configuring OpenPnP (which runs on an attached PC.)

[Erich] does not recommend this conversion for anyone who is not very familiar with electronics, or has any worries about voiding warranties. Barring that, he suspects the conversion could be done in about a day or two’s worth of focused work. It took him two weeks, including time spent fine-tuning the first production job. He says the bulk of the time was spent on configuration, but he has shared his configuration on GitHub in the hopes that it will save a lot of time for anyone using the same hardware.

After populating some 300 boards and placing over 7000 parts, he’s very happy with the results. The machine places between 600 and 700 parts per hour, so speed might not be amazing but it’s perfectly serviceable. [Erich] finds that while the machine runs a little slower than it did with the original controller, it also runs much smoother and quieter overall. In return he gets what he truly wanted: a pick and place machine whose operation and configuration is entirely open and accessible. You can see it in action in the video, embedded below.

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Raspberry Pi Takes Control Of Ham Radio

June 24, 2020 by Al Williams 16 Comments

Today’s ham radio gear often has a facility for remote control, but they most often talk to a computer, not the operator. Hambone, on the other hand, acts like a ham radio robot, decoding TouchTone digits and taking action — for example, keying the radio and reading off the weather — in response to the commands received.

The code is in Python and uses numpy’s fast Fourier transform to identify digits. We’d be interested to test the performance of that compared to doing a Goertzel to specifically probe for the 8 digit tones: there are four row tones and four column tones. On the other hand, the FFT is handy and clearly works fast enough for this application.

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Boot-To-BASIC Box Packs A Killer Graphics Engine

June 23, 2020 by Lewin Day 58 Comments

In the early days of the home computer era, many machines would natively boot into a BASIC interpreter. This was a great way to teach programming to the masses. However on most platforms the graphics routines were incredibly slow, and this greatly limited what could be achieved. In 2020 such limitations are a thing of the past, with the Color Maximite 2. (Video, embedded below.)

The Color Maximite 2 is a computer based around the STM32H743IIT6 microcontroller, packing a Cortex-M7 32-bit RISC core with the Chrom-ART graphics accelerator. Running at 480MHz it’s got plenty of grunt, allowing it to deliver vibrant graphics to the screen reminiscent of the very best of the 16-bit console era. The Maximite 2 combines this chip alongside a BASIC interpreter complete with efficient graphics routines. This allows for the development of games with fast and smooth movement, with plenty of huge sprites and detailed backgrounds.

[cTrix] does a great job of demonstrating the machine, designed by [Geoff Graham] and [Peter Mather]. Putting the computer through its paces with a series of demos, it shows off the impressive visual and audio capabilities of the hardware. It serves as an excellent spiritual successor to BlitzBASIC from back in the Amiga days. Particularly enjoyable is seeing a BASIC interpreter that adds syntax highlighting – making parsing the code far easier on the eyes!

We’d love to see this become an off-the-shelf kit, as it’s clear the platform has a lot to offer the retro hobbyist. It’s certainly come a long way from the original Maximite of nearly a decade ago. Video after the break.

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