New Part Day: Two Millimeter Addressable LEDs

July 10, 2019 by Brian Benchoff 57 Comments

The WS2812, or “Neopixels”, or whatever you want to call them, are the standard when it comes to adding blinky to anything. These chips are individually addressable RGB LEDs, which you’ve seen in many LED strips and a thousand other products. These LEDs are rather big compared to normal, dumb LEDs, measuring 5 mm on each side. Here are WS2812s packed into a 2 mm x 2 mm square package. It’s the smallest and brightest blinky that works the same as the WS2812s you know and love.

This is the latest product from Worldsemi. We’ve heard of these before, but damned if we could find a supplier or even a price. Now they’re on AliExpress, at a price of $8 USD per 100, shipping not included.

Electrically, these appear to have the same properties of the normal, 5050-size WS2812 LEDs. Apply power and ground to two pins, send data in on one pin, and connect the next LED in the strand to the remaining pin. Yes, it requires a bit of work to turn this into a display, but microcontrollers are very fast now and have plenty of RAM. Attach a BeagleBone and you’ll be able to drive as many as your glowing heart desires.

If you’re wondering what the coolest project imaginable for these LEDs is, here’s the math: the largest (common) PCB panel for your random board house is 16 by 22 inches. Assuming a 3 mm pixel pitch, that means the largest PCB display you can make with these LEDs is 135 by 186 pixels, call it 120 by 180 just to make things easy. That’s 21,600 LEDs, at a cost of about $2,000. I would not recommend reflowing these, and assuming soldering a LED every thirty seconds, it will take about a month to solder them all by hand. There’s your project, now get to it.

Using Super-Efficient Solar Cells To Keep Your Electric Car’s Battery Topped Up

July 10, 2019 by Maya Posch 96 Comments

Who hasn’t thought of sticking a couple of solar panels onto an electric car’s roof to keep its battery at 100% charge while it’s parked out in the sun? While usually deemed impossible due to the large number and weight of PV solar cells required to get the necessary amount of energy, this hasn’t kept Toyota’s engineers from covering one of their Prius cars with 34+% efficient solar cells.

Some may remember the solar roof option which Toyota previously offered years ago. That system produced a mere 50 W and was only used for things like running the AC fans, indirectly extending the battery charge. In 2016 Toyota brought back this system, in a much improved version. This upped the power output to 180 W, allowing it to power all secondary electronics in the Prius, even allowing it to add a few extra kilometers (roughly 6.1 km/day) to the Prius’ range if one were so inclined.

This newest prototype pretty much goes for broke, reminding us of the cars used in the World Solar Challenge, such as the Dutch Stella and Stella Lux positive-energy solar cars by the team at the University of Eindhoven. Who coincidentally have done a spin-off, setting up a company to produce the Lightyear One, which at least on paper sounds amazing, and potentially may never have to plug it in.

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Robot Harvesting Machine Is Tip Of The Agri-Tech Iceberg

July 9, 2019 by Pat Whetman 24 Comments

Harvesting delicate fruit and vegetables with robots is hard, and increasingly us humans no longer want to do these jobs. The pressure to find engineering solutions is intense and more and more machines of different shapes and sizes have recently been emerging in an attempt to alleviate the problem. Additionally, each crop is often quite different from one another and so, for example, a strawberry picking machine can not be used for harvesting lettuce.

A team from Cambridge university, UK, recently published the details of their lettuce picking machine, written in a nice easy-to-read style and packed full of useful practical information. Well worth a read!

The machine uses YOLO3 detection and classification networks to get localisation coordinates of the crop and then check if it’s ready for harvest, or diseased. A standard UR10 robotic arm then positions the harvesting mechanism over the lettuce, getting force feedback through the arm joints to detect when it hits the ground. A pneumatically actuated cutting blade then attempts to cut the lettuce at exactly the right height below the lettuce head in order to satisfy the very exacting requirements of the supermarkets.

Rather strangely, the main control hardware is just a standard laptop which handles 2 consumer grade USB cameras with overall combined detection and classification speeds of about 0.212 seconds. The software is ROS (Robot Operating System) with custom nodes written in Python by members of the team.

Although the machine is slow and under-powered, we were very impressed with the fact that it seemed to work quite well. This particular project has been ongoing for several years now and the machine rebuilt 16 times! These types of machines are currently (2019) very much in their infancy and we can expect to see many more attempts at cracking these difficult engineering tasks in the next few years.

We’ve covered some solutions before, including: Weedinator, an autonomous farming ‘bot, MoAgriS, an indoor farming rig, a laser-firing fish-lice remover, an Aussie farming robot, and of course the latest and greatest from FarmBot.

Video after the break:

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The Theremin Gets A Voice

July 9, 2019 by Inderpreet Singh 10 Comments

Every once in a while, we come across a project that adds a ridiculously good twist on an existing design. This is exactly what [Xiao Xiao] and the team at LAM research group at the Institut d’Alembert in Paris have done. Their project T-VOKS is a singing and Speaking Theremin that is sure to drive everyone in the office crazy. (YouTube link, embedded below for your viewing pleasure.)

For the uninitiated, the Theremin is an electronic music instrument that does not require physical contact. Instead, it uses two antennas to sense the distance of the operators hands and uses that to modulate the pitch and volume of the output audio. From music concerts to movie background music to even scaring the neighbours, this instrument can do it all.

T-VOKS is a different take on the instrument, and it interfaces with a voice synthesizer to sing. There is an additional sensor that is used for the syllable sequencing, and the video below shows the gadget in operation. The icing on the cake is the instrument playing, or should that be singing in an actual concert. There is also a research paper detailing the operation on Dropbox[PDF] if you need the nitty-gritty.

We wonder how a TTS engine would work with this idea and hope to see some more projects like it in the future. Fore those looking to get started, have a look at the build guide for a DIY theremin.

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Space Age Bitcoin Mining On An Apollo AGC

July 9, 2019 by Dan Maloney 6 Comments

Imagine you’ve got an Apollo Guidance Computer, the machine that took men to the Moon 50 years ago. You’ve spent ages restoring it, and now it’s the only working AGC on the planet. It’s not as though you’re going to fly to the Moon with it, so what do you do with it? Easy – turn it into a perfectly awful Bitcoin mining rig.

The AGC that [Ken Shirriff] and others have been restoring barely resembles a modern computer. The AGC could only do about 40,000 operations per second, but raw speed was far less important than overall reliability and the abundant IO needed to run a crewed spacecraft. It was a spectacular success on the Apollo missions, but [Ken] wanted to know if turning it into a Bitcoin mining rig was possible.

[Ken] gives a great overview of how Bitcoin mining works, with one of the best explanations of the hashing algorithm we’ve seen. Getting that to run on the AGC was no mean feat, especially with limits imposed by the memory addressing scheme and the lack of machine instructions for manipulating words. He eventually got it working, though, clocking in at a screaming 10.3 seconds per Bitcoin hash. [Ken] estimates that the first coin will be successfully mined in a mere 400 zettaseconds, which is about a billion times older than the universe. With about 13 quadrillion years to the first ka-ching, you have plenty of time to watch a block mined in the video below; alas, it was an old block, so no coins were awarded to compensate the team for their efforts.

This isn’t the first time [Ken] has implemented a useless Bitcoin mine. The Xerox Alto mine was actually fast compared to the AGC, but it sure beats the IBM mainframe and punchcards.

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Liquid Damaged MacBook Saved With A Keen Eye

July 9, 2019 by Tom Nardi 20 Comments

Even among those of us with a penchant for repairing electronics, there are some failures which are generally considered too severe to come back from. A good example is liquid damage in a laptop; with so many components and complex circuits crammed into such a small area, making heads or tails of it once the corrosion sets in can be a real nightmare. Especially in the case of an older laptop, the conventional wisdom is to try and recover your files and then buy a new one.

But as we’ve come to learn, [Jason Gin] is not a man who often finds himself concerned with conventional wisdom. After finding an older MacBook with suspected liquid damage, he decided to see what it would take to restore it to working order. According to a note on the device, the screen was dead, the USB ports were fried, the battery didn’t take a charge, and it wouldn’t boot. No problem then, should be easy.

Upon opening up the circa-2012 laptop, [Jason] found the machine to be riddled with corrosion. We’re not just talking surface gunk either. After giving everything a good cleaning with isopropyl alcohol, the true extent of the damage became clear. Not only had traces on the PCB rotted away, but there were many components that were either damaged or missing altogether. Whatever spilled inside this poor Mac was clearly some nasty stuff.

[Jason] used OpenBoardView to pull up schematics and diagrams of the motherboard, and started the arduous task of visually comparing them to his damaged unit. In some areas, the corrosion was so bad he still had trouble locating the correct traces and pads. But with time and effort, he was able to start probing around and seeing what components had actually given up the ghost.

For the USB ports it ended up being a bad 10-microfarad ceramic capacitor, but for the LCD, he ended up having to replace the entire backlight driver IC. The prospect of working on this tiny BGA-25 device might have been enough for some to throw in the towel, but compared to the hand-soldered magnet wire repairs required elsewhere on the board, [Jason] says the installation of the new LP8550 chip was one of the easier aspects of the whole operation.

The write-up is a great read if you like a good repair success story, and we especially like the way he documented his diagnosis and resulting work on a per-system basis. It makes it much easier to understand just how many individual fires [Jason] had to put out. But if you’re more interested in feats of steady-handed soldering, check out his recent project to add a PCI-E slot to the Atomic Pi.

FlexLED Is A Unique Take On Persistence Of Vision

July 9, 2019 by Lewin Day 13 Comments

Many hackers have experimented with the persistence of vision effect. Whip around a bunch of LEDs, flash them at just the right times, and it’s possible to make images to appear to hang in the air. There’s plenty of ways to do this, whether by manually shaking the LEDs by hand, spinning them around, or even putting them on your bike wheels. [Carl Bugeja] went a different route, taking advantage of the possibilities created by flex PCBs.

[Carl]’s project goes by the name FlexLED. This aptly describes the build, which, in prototype form, mounts a single LED on the end of a flex PCB. The PCB itself has a pattern of traces creating a coil, which enable it to interact with magnetic fields more strongly. By passing the right current through the coil, the flexible PCB can be made to flap up and down, moving the LED on the end at a rapid rate. By then controlling the flashing of the LED, it’s possible to create a persistence of vision effect.

Currently fitted with only one LED, capable of 3 colors, the visual display of the FlexLED is somewhat limited. However, [Carl] reports the effect is more impressive in person than on camera, and is already working on plans to scale up the project to a multi-LED diplay.

POV technology can do some pretty impressive things – even volumetric displays are possible. If you’re working on something yourself, be sure to let us know. Video after the break.