Clever Wedges That Will Increase Your PCB Assembly Yield

If there’s one thing that will bring down the yield of your PCB assembly, it’s your solder paste. Put too much on, and you’ll get bridged leads. If you don’t put enough on, that pad might not make good contact. [ScalarElectric] has an amazing trick that’s sure to astonish and astound. Just use wedges and you’ll get better yield with fine-pitched components.

The trick here is to define the cream/solder paste layer of each package as a wedge on each pad instead of the usual rectangle. This gives a few benefits, the largest being the increased gap between paste shapes. You’re also getting a reduction in the total amount of paste applied, and a subsequent improvement in yield. (Reportedly, we’d love to see some data on this.)

PCB design tools usually have a way to alter the size of the cream/solder paste layer of a design, and indeed one option is to simply shrink the size of the paste layer elements. The trick to the wedges is increasing the total distance between solderpaste blobs while keeping the total amount of solderpaste high. This technique can be used down to 0.5mm pitch parts, and everything works like a charm.

While this is a little outside of our wheelhouse here at Hackaday — it is, after all, a novel use of existing tools that is mostly applicable to electronic design and production. [Ed Note: Sarcasm.] You can check out a few pics of this technique in the slideshow below. If you test this technique out, be sure to let us know how it went!

This slideshow requires JavaScript.

Giving An Old Mac Spotify

The Macintosh SE/30 is the greatest computer ever made, and I’m not saying that just because I’m sitting on a cache of them, slowly selling them to computer collectors around the world. No, the SE/30 is so great because of how powerful it is, and how much it can be expanded. A case in point: here’s an SE/30 that’s a Spotify player. Oh, it does it over WiFi, too.

You might be asking yourself how a computer from 1989 (it’s late enough in the year that we can safely say this computer is thirty years old) can possibly play music over the Internet. While the SE/30 supported an astonishing 128 Megabytes of RAM, it’s still just a bit too slow to play MP3s or any modern audio codec. The 68030 CPU just wasn’t fast enough to play audio, to say nothing of streaming it over a network connection. The trick is that this SE/30 is simply a remote for Spotify Connect. You could theoretically get the Mac to speak, “Alexa, play Despacito” and get the same functionality, but that’s not fun, is it? You need to do it wirelessly.

This is a continuation of one of [ants] earlier hacks that basically put a WiFi to Ethernet bridge inside an SE/30. Tie that together with a Finder extension and you have System 7, with WiFi. That’s a connection to the Internet, but [ants] actual wrote an app to connect to a Spotify playlist, browse tracks, and display album art in beautiful 1-bit color. Writing the app involved dealing with OAuth, which means the MacPlayer isn’t entirely standalone; some of it must be done on a ‘modern’ device. This, along with porting a conversion utility that translates UTF-8 text encoding into something the Mac can understand ties everything together.

With all those pieces, the SE/30 becomes a handsome, functional piece of art. Apple is never going to release a computer like this again, and you’re not going to find a touchbar MacBook being used like this in thirty years time.

Seeing Like Bees With Ultraviolet Photography

When it comes to seeing in strange spectrums, David Prutchi is the guy you want to talk to. He’s taken pictures of rocks under long, medium and short UV light, he’s added thermal imaging to consumer cameras, and he’s made cameras see polarization. There’s a lot more to the world than what the rods and cones on your retina can see, and David is one of the best at revealing it. For this year’s talk at the Hackaday Superconference, David is talking about DIY Ultraviolet Photography. It’s how bees see, and it’s the bees knees.

Continue reading “Seeing Like Bees With Ultraviolet Photography”

That’s A Lisp Machine In Your Pocket

Computer languages have always advanced faster than computer hardware. Case in point: we’re just now getting CPU instructions for JavaScript floating point numbers. The 1970s and 80s wasn’t the garbage fire of JavaScript instructions in silicon, instead they were all about garbage collection. Lisp machines were CPUs designed to run Lisp efficiently. They were great, until the companies responsible realized you had to sell a product to stay in business. Combine an interesting architecture with rarity and historical interest, and you have a centerpiece of any retrocomputing enthusiasts collection. Yes, we all want a Lisp machine.

Now there’s an interesting project on CrowdSupply that will make that possible. It’s the MakerLisp Machine, a credit card-sized computer that runs bare-metal Lisp.

We first saw the MakerLisp Machine in its raw prototype form at VCF West last August, and it was in a very, very raw state. That was just a prototype, though, but the MakerLisp business card-sized computer still features the Zilog eZ80 running at 50MHz. The basic board includes a USB port for a serial connection and a microSD card slot for storage. It boots into a Lisp environment, and you don’t even have to use a NuBus card. We’re living in the future here.

Because this is a credit card-sized computer, there is of course an expansion board that breaks everything out, including the GPIOs. Being a Z80, you’re also going to get CP/M support, but the real story here is Lisp, in your pocket.

Can Magnets Replace The Spring In A Pogo Stick?

Betteridge’s law of headlines states that any headline that ends in a question mark can be answered by the word ‘no’. It’s the case with articles asking if Millennials are responsible for all of the world’s ills, or if some technology is the future. So we come to this fascinating case of native content (amusing, veiled advertising) from a store that sells really, really powerful magnets. The title of the article asks if magnets can replace the spring in a pogo stick. The answer, of course, is no, but it does provide a fascinating look at linear versus exponential growth.

A pogo stick is simply a spring with a set of handles and footholds that is the subject of a great number of hilarious YouTube videos, at least one of which is impressive. The physics of a pogo stick is determined entirely by Hooke’s Law, and is a linear equation, not counting the strength of a spring and the yield point of steel, but this is a pogo stick we’re talking about. Magnets, on the other hand, obey the inverse square law. Is it possible to fit an exponential function to fit a linear function? No. No, it is not.

I refuse to believe this is the first use of the phrase, ‘immensely disappointing pogo stick’

But a lack of understanding of the basic forces of nature never stopped anyone, so the folks at K & J Magnetics made a really neat test. They printed out a 1/8th scale pogo stick, complete with a spring. It worked like any pogo stick would. Then they took out the spring and put a few magnets where the spring should go. How did that work? Well, it bottomed out and was an immensely disappointing pogo stick.

If a problem is worth solving, it’s worth solving wrongly, so more magnets were added. Mounting three magnets onto a pogo stick gave the same exponential force, but still not enough. Four, five, and six magnets were added to the model pogo stick, and while six magnets gave this model pogo enough force to be ‘bouncy’, there simply wasn’t enough space for the pogo stick to compress.

The takeaway from this experiment is extremely obvious in retrospect, but probably too subtle for a lot of people. There’s a difference between a linear relationship and and exponential relationship. There’s also a video, you can check that out below.

Continue reading “Can Magnets Replace The Spring In A Pogo Stick?”

A Deep Dive Into Low Power WiFi Microcontrollers

The Internet of Things is eating everything alive, and the world wants to know: how do you make a small, battery-powered, WiFi-enabled microcontroller device? This is a surprisingly difficult problem. WiFi is not optimized for low-power operations. It’s power-hungry, and there’s a lot of overhead. That said, there are microcontrollers out there with WiFi capability, but how do they hold up to running off of a battery for days, or weeks? That’s what [TvE] is exploring in a fantastic multi-part series of posts delving into low-power WiFi microcontrollers.

The idea for these experiments is set up in the first post in the series. Basically, the goal is to measure how long the ESP8266 and ESP32 will run on a battery, using various sleep modes. Both the ESP8266 and ESP32 have deep-sleep modes, a ‘sleep’ mode where the state is preserved, a ‘CPU only’ mode that turns the RF off, and various measures for sending and receiving a packet.

The takeaway from these experiments is that a battery-powered ESP8266 can’t be used for more than a week without a seriously beefy battery or a solar panel. Run times are much longer with an open network as compared to a secured network, and that security eats up a ton of power: connecting to a secure network every now and again means your ESP might only run for a day, instead of a week.

There is another option, though: the ESP32. While the ’32 is vastly more powerful and more capable than the ESP8266, it also has a few improved features that help with power consumption. Importantly, there’s a bug in the ESP8266 where it drops into modem sleep instead of light sleep about half the time. This error was fixed in the ESP32, but all that power does come at a cost. On the whole, if you’re concerned about security, the ESP32 is slightly better, simply because it does the ‘security’ part of connecting to a WiFi network faster. This is really a remarkable amount of testing that’s gone into this write-up, so if you’re developing something battery-powered with any ESP, it’s well worth the read.

Hackaday Links: December 16, 2018

Microsoft is really leaning into vaporwave these days. Microsoft is giving away knit Windows sweaters to social media influencers. Is it for an ugly sweater contest? Maybe, or maybe Microsoft is capitalizing on the mid-90s AESTHETIC. Recently, Apple got back in their 90s logo game with the release of a few ‘rainbow Apple’ t-shirts. The spirit of the 90s lives on in tech culture.

Have a Hackerspace? Frack is organizing the great Inter-hackerspaces Xmas goodies swap! Since your hackerspace is filled with weird ephemera and random crap, why not box it up and send it out to another hackerspace? You’ll probably get another random box of crap in return!

Just an observation looking for commentary, but is Thingiverse slow these days? It seems really, really, really slow these days.

The Blockchain makes it to the Apple II! By far, the most interesting thing in tech right now is the blockchain, with AI, at the edge. This will get your Merkle trees tinglin’ with some AI, and 5G is where it’s at. We’re back with cylinder computing this time, and this is the greatest achievement that will synthesize brand new paradigms. Of course, if it weren’t for millennials, we’d have it already.

There’s a new portable console out there, and it’s at the top of everyone’s Christmas lists. The SouljaGame Handheld is a rebrand of what’s available on AliExpress. What makes this one different? It has Soulja Boy’s name on it. If you couldn’t get your hands on the SouljaGame Handheld, don’t worry: Post Malone Crocs are available on eBay for about $300.