The Crawlspace Crawler

This crawlspace crawler FPV robot is a fairly simple build. [Jeff G] bought a boxy chassis kit with frame, motors, and wheels, mounted lights and camera, and we get to see it in action (video, embedded below).

As always, the details are where it’s at, and his overview covers most of the high points. [Jeff] went for relatively slow 60 RPM motors so that he’d have plenty of grunt. The FPV setup is particularly simple – he bought a cheap Flysky i6 transmitter and receiver, and an Eachine TX05 all-in-one camera and transmitter. An interesting choice was a USB UVC video receiver so he can watch the footage on a computer, tablet, or a cell phone, which means he didn’t have to shell out for expensive FPV goggles. We also love the sticks-and-zip-ties used as feelers, letting him know when he’s about to get stuck, but that also serve as a visual frame for the camera.

The FPV Contest just came to an end, and we’ll be announcing the winners soon! If you find any inspiration there for your own project, [Jeff]’s simple basis here should get you started on the right track.

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Fool A Drone With A Fixed Battery

Lithium-ion and lithium-polymer rechargeable batteries have given us previously impossible heights of electronics power and miniaturization, but there’s a downside they have brought along with them. When a battery pack has to contain electronics for balancing cells, it’s very easy for a manufacturer to include extra functions such as locking down the battery. Repair a battery, replace cells, or use a third-party battery, and it won’t work. [Zolly] has this with a DJI Mavic Mini pack, and shares with us a method for bypassing it.

The pack talks to the multi-rotor with a serial line, and the hack involves interrupting that line at the opportune moment to stop it telling its host that things are amiss. Which is a good start — but we can’t help hacing some misgivings around the rest of the work. Disconnecting the balance line between the two cells and fooling the Battery Management System (BMS) with a resistive divider seems to us like a recipe of disaster, as does bypassing the protection MOSFETs with a piece of wire. It may work, and in theory the cells can be charged safely with an external balance charger, but we’re not sure we’d like to have a pack thus modified lying around the shop.

It does serve as a reminder that BMS boards can sometimes infuriatingly lock their owners out. We once encountered this with a second-generation iBook battery that came back to life after a BMS reset, but it’s still not something to go into unwarily. Read our guide to battery packs and BMS boards to know more.

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The Problem With Passwords

By now it’s probable that most readers will have heard about LastPass’s “Security Incident“, in which users’ password vaults were lifted from their servers. We’re told that the vaults are encrypted such that they’re of little use to anyone without futuristic computing power and a lot of time, but the damage is still done and I for one am glad that I wasn’t a subscriber to their service. But perhaps the debacle serves a very good purpose for all of us, in that it affords a much-needed opportunity for a look at the way we do passwords. Continue reading “The Problem With Passwords”

Veteran Polaroid Camera Lives Again, With Film Conversion

Browsing the thrift stores will net an amazing array of old cameras for dirt cheap prices, meaning that a film enthusiast can have plenty of fun without wasting money they could spend on the film itself. Unfortunately many of the more interesting cameras are those which use film long out of production, leaving the photographer with a need to improvise using a more modern film that’s still in production.

[Nicholas Morganti] has just such a camera, a Polaroid Big Shot, a 1970s instant camera designed for portrait work, for which the Polaroid 100 film packs are sadly a distant memory. Leave it on the shelf? Not likely, he’s adapted it to work with Fuji Instax 210, a readily available and cheap instant film.

Polaroid 100 and Instax 210 are almost the same size, but are not close enough for a direct fit. An Instax cartridge can be persuaded to fit into the Big Shot, but it’s a tight fit that puts strain on the aged Polaroid hinges. Even then the Polaroid rollers and photo ejection system are very different from those in the Fuji, so it involved a workflow in which the cartridge had to be unloaded in a darkroom between shots and processed through a real Fuji camera for the final picture.

His eventual solution takes a less camera-straining tack, still requiring a darkroom but taking an individual unexposed frame from an Instax pack and placing it in the Big Shot on an adapter plate. The result is a usable if a little cumbersome workflow for vintage Polaroid pictures, something plenty of instant photography enthusiasts will be thankful for. If you’re one of them, you might like to read our look at the process.

2022: As The Hardware World Turns

Well folks, we made it through another one. While it would be a stretch to call 2022 a good year for those of us in the hacking and making community, the light at the end of the tunnel does seem decidedly brighter now than it did this time 365 days ago. It might even be safe to show some legitimate optimism for the year ahead, but then again I was counting on my Tesla stocks to be a long-term investment, so what the hell do I know about predicting the future.

Eh, my kids probably weren’t going to college anyway.

Thankfully hindsight always affords us a bit of wisdom, deservedly or otherwise. Now that 2022 is officially in the rearview mirror, it’s a good time to look back on the highs (and lows) of the last twelve months. Good or bad, these are the stories that will stick out in our collective minds when we think back on this period of our lives.

Oh sure, some might wish they could take the Men in Black route and forget these last few years ever happened, but it doesn’t work that way. In fact, given the tumultuous times we’re currently living in, it seems more likely than not that at some point we’ll find ourselves having to explain the whole thing to some future generation as they stare up at us wide-eyed around a roaring fire. Though with the way this timeline is going, the source of said fire might be the smoldering remains of an overturned urban assault robot that you just destroyed.

So while it’s still fresh in our minds, and before 2023 has a chance to impose any new disasters on us, let’s take a trip back through some of the biggest stories and themes of the last year.

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The STEAM Connection Danielle Boyer and mentee Vinaya Gunasekar build robots

Wearable SkoBots Full Of STEAM And Vanishing Indigenous Languages

[Danielle Boyer] is Ojibwe: Sault Ste Marie Tribe and passionate about preserving vanishing indigenous languages. She’s invented a shoulder-worn talking companion, called a SkoBot, to teach STEAM to children through building robots programmed with indigenous language lessons and founded the STEAM Connection to give them away.

Through her Every Kid Gets a Robot program, more than 8,000 ESP32-based kits have been distributed to students. With a total cost of less than $20 USD, the 3D printed bots help democratize access to robotics. As many rural areas lack access to high-speed internet, they are designed to be controlled locally by the student’s phone.

During an interview on WBUR in Boston, [Danielle] recalled that one of her students once said that she was the first Native person they’d seen in robotics, and she inspired them to get into it. “That really made me emotional and inspired to see the power that us being ourselves has and being authentic to ourselves, to our community, I just think that’s such a beautiful thing.”

Learn more about the impactful and fun work [Danielle] is doing at the STEAM Connection that scored her an invite to the White House, see a preview in the GMA video after the break, and watch for her plant-based BioBotz coming later this year.

This isn’t the first time we’ve seen robots invade the classroom: from student-built “Battle Bots” to the modular 3D printed SimpleSumo project, these educational initiatives can help teach the basics of electronics and software development in a more engaging way than simply reading theory from a textbook.

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A Single Ended Vacuum Tube Amplifier With A Modern Twist

Despite the oldest solid state audio circuitry now qualifying for a pension and a bus pass where this is being written, the thermionic tube retains a foothold in the world of audio — cherished by enthusiasts for the warm sound it is claimed to impart. For  the electronics enthusiast a tube audio amplifier makes for an interesting and unusual project, and for that reason it’s one tackled by many. [Keri Szafir] is no exception, and she’s produced a stereo tube amp with a few modern features.

Electrically it’s a relatively conventional single-ended design using a double triode and a power pentode for each channel. It follows a so-called ultra-linear circuit, with a tap on the output transformer feeding one of the pentode’s grids. The modern features come via a switched Bluetooth input and a motorized volume control, something that would have never been found on such an amp when they were the cutting edge.

We have to admit a soft spot for this type of amp, and we particularly like this one for its very period construction style using cable lacing to keep the wiring under control. We more often see these amps using the cheaper integrated triode-pentode tubes which makes them especially easy to build, so the separate preamp is a little different. We’re not sure we’d have spent extra on the fancy E88cc tubes though. Continue reading “A Single Ended Vacuum Tube Amplifier With A Modern Twist”