Low-voltage DC power electronics are an exciting field right now. Easy access to 18650 battery cells and an abundance of used Li-Ion cells from laptops, phones, etc. has opened the door for hackers building their own battery packs from these cheap cells. A big issue has been the actual construction of a pack that can handle your individual power needs. If you’re just assembling a pack to drive a small LED, you can probably get by with spring contacts. When you need to power an e-bike or other high power application, you need a different solution. A spot welder that costs $1000 is probably the best tool, but out of most hackers’ budget. A better solution is needed.
Enter [Micah Toll] and his Vruzend battery connectors, whose Kickstarter campaign has exceded its goal several times over. These connectors snap onto the ends of standard 18650 cells, and slot together to form a custom-sized battery pack. Threaded rods extend from each plastic cap to enable connection to a bus bar with just a single nut. The way that you connect each 18650 cell determines the battery pack’s voltage and current capability. There are a couple of versions of the connector available through the campaign, and the latest version 2.0 should allow some tremendously powerful battery pack designs. The key upgrade is that it now features corrosion-resistant, high-power nickel-plated copper busbars allowing current up to 20A continuous. A side benefit of these caps instead of welded tabs is that you can easily swap out battery cells if one fails or degrades over time. Continue reading “Assemble Your Own Modular Li-Ion Batteries”→
Simple tools are great, but sometimes it is most convenient to just use something easy, and since it gets the work done, you don’t try out some of the other features. Tinkercad is a great example of that kind of program. It is actually quite powerful, but many people just use it in the simplest way possible. [Chuck] noticed a video about making a 3D-printed hinge using Tinkercad and in that video [Nerys] manually placed a bunch of hinges using cut and paste along with the arrow keys for positioning. While it worked, it wasn’t the most elegant way to do it, so [Chuck] made a video showing how to do it parametrically. You can see that video below, along with the original hinge video.
There are really two major techniques [Chuck] shows. First, he adds the necessary pieces to create the hinges to the Tinkercad toolbox. That makes it really simple to add them to any of your future designs. Second, he uses a combination of numeric parameters and duplication to quickly and precisely place the hinge components across another object — in this case a Batman logo.
Over the last few months, the folks over at the SupplyFrame Design Lab, home to Hackaday meetups, the Hackaday Superconference, and far, far too many interesting tools, have been spending their time visiting workshops and hackerspaces to see how they tick. Staff Designer of the Design Lab, [Majenta Strongheart], recently took a trip down the road to Caltech to check out their hackerspace. Actually, it’s a rapid prototyping lab, but a rose by any other name…
The prototyping lab at Caltech exists for a few reasons. The first, and most important, are the graduate students. This is a research facility, after all, and with research comes the need to make stuff. Whether that’s parts for biomechanical fixtures, seismology experiments, or parts for a radio telescope, there’s always going to be a need to make mechanical parts. The rapid prototyping lab is also available to undergraduates. Many of the courses at Caltech allow students to build robots. For example, when the DesignLab staff was filming, the students in Mechanical Engineering 72 were taking part in Tank Wars, a robot competition. Here, students built little rovers built to climb over obstacles and traverse terrain.
As far as tech goes, this is a real shop. There are vintage knee mills, manual lathes, but also fancy CNC lathes, Tormach mills, and laser cutters galore. The amount of tooling in this lab has slowly accumulated over decades, and it shows. Right next to the bright white Tormach, you’ll find drill presses that are just that shade of industrial green. It’s a wonderful space, and we’re happy the faculty and students at Caltech allowed us to take a look.
Electric vehicles are fertile ground for innovation because the availability of suitable motors, controllers, and power sources makes experimentation accessible even to hobbyists. Even so, [John Dingley] has been working on such vehicles since about 2009, and his latest self-balancing electric unicycle really raises the bar by multiple notches. It sports a monstrous 3000 Watt brushless hub motor intended for an electric motorcycle, and [John] was able to add numerous touches such as voice feedback and 1950’s styling using surplus aircraft and motorcycle parts. To steer, the frame changes shape slightly with help of the handlebars to allow the driver’s center of gravity to shift towards one or the other outer rims of the wheel. In a test drive at a deserted beach, [John] tells us that the bike never went above 20% power; the device’s limitations are entirely by personal courage. Watch the video of the test, embedded below.
If [Nixie]’s setup looks familiar, it might be because we featured his plasma experiments a few days ago. He was a little cagey then about his goal, but he’s come clean with his desire to make his own FETs (a project that is his 2018 Hackaday Prize entry). Doing so will require not only creating stable plasmas, but also the ability to move substrates around inside the vacuum chamber. Taking inspiration from the slender and maneuverable instruments surgeons use for laparoscopic procedures, [Nixie] is working on a miniature arm that will work inside his vacuum chamber. The video below is a 3D-printed proof-of-concept model in action, and shows how the arm’s segments will be controlled by cables. What’s really interesting is that the control cables will not penetrate the vacuum chamber — they’ll be moved right through the glass wall using magnets.
Occasionally you run across a product that you just know is simply too good to be true. You might not know why, but you’ve got a hunch that what the bombastic phrasing on the package is telling you just doesn’t quite align with reality. That’s the feeling I got recently when I spotted the “LED intellibulb Battery Backup” bulb by Feit Electric. For around $12 USD at Home Depot, the box promises the purchaser will “Never be in the dark again”, and that the bulb will continue to work normally for up to 3.5 hours when the power is out. If I could repurpose that to make a tiny UPS for a microcontroller project of my own, it could be even more useful.
Now an LED light bulb with a battery in the base isn’t exactly rocket science, we can understand the product conceptually at a glance. But as they say, the devil is in the details. The box claims the bulb consumes 8.5 watts, but a battery with enough capacity to run such a load for 3.5 hours would be far too large to fit inside of a light bulb. Obviously there’s more to the story.
On the side of the box, in the smallest font used on the whole package, we get our clue. The bulb drops down to 200 lumens when in battery backup mode, or roughly as bright as a cheap LED flashlight. Now things are starting to come together. Without even opening the device, we can be fairly sure it will contain two separate arrays of LEDs: one low set for battery, and a brighter set to run when the bulb has AC power.
Still, I tend to be of the opinion that anything less than $20 or so is worth cracking open to see what makes it tick. Even if the product itself is underwhelming, there’s a chance the internal components could be useful or interesting. With that in mind, let’s see what’s inside a battery backup light bulb, and what we might be able to do with it.
For most people, a Post-It note or dry-erase board suffices to ensure that household consumables are replenished when they’re used up. But hackers aren’t like most people, so this surplus barcode scanner turned kitchen inventory manager comes as little surprise. After all, if something is worth doing, it’s worth overdoing.
[Brian Carrigan]’s project began with a chance discovery of an old barcode scanner in his local scrap store. Questions as to why we can never find bargains like a $500 scanner for six bucks aside, [Brian] took the scanner home for a bit of reverse engineering. He knew it used RS-232 but it had been unceremoniously ripped from its connectors, so identifying pins took some detective work. With power and data worked out and the scanner talking to a Raspberry Pi, [Brian] set about integrating it into Wunderlist, a cloud-based list management app. Now when someone eats the last Twinkie, a quick scan of the package looks up the product name via an API call to the UPC database and posts it to Wunderlist. And we’ll bet the red laser beams bouncing around the kitchen make a great nightlight too.