SOICbite: A Program/Debug Connector For An SOIC Test Clip

June 13, 2019 by Ted Yapo 40 Comments

The problem is well-known: programming and debug headers consume valuable board space and the connectors cost money. Especially troublesome are the ubiquitous 100-mil pin headers, not because they’re expensive, but because they’re huge, especially along the z-axis. If you’re building miniature devices, these things can take up a ridiculous amount of space. With some clever thinking, [Simon Merrett] has found a way to re-use something many of us already have — an SOIC-8 test clip — to connect to a special footprint on the PCB without requiring another connector. He calls the system SOICbite.

The SOIC clip attaches to a footprint consisting of eight pads, four on each side of the PCB, plus five non-plated-through holes, which serve to anchor the clip in place. The idea of mating a PCB footprint directly with a removable connector isn’t entirely new — Tag Connect has been doing this for a while, but the connectors are expensive and single-sourced. On the other hand, SOIC test clips of varying quality are available from a number of vendors, including dirt-cheap deals on your favorite websites. The one disadvantage we can see is that the SOICbite footprint must be at the edge of the PCB to properly mate with the clip. The savings in space and cost may well make up for this, however.

[Simon] has made his KiCAD footprint available in a GitHub repo, and has offered to host footprints for any other CAD package there as well. So, fire up your preferred tool and draw one up for him to get these things widely adopted, because we think this is a great idea.

For the commercial alternative, check out our coverage of Tag Connect back in 2014.

Captivating ESP32 Camera Hack

June 10, 2019 by Inderpreet Singh 16 Comments

You can never have enough DIY devices at home, so when you look at an ESP32 module that comes with the camera, you automatically start getting ideas. [Daniel Padilla] wanted a way to deploy DIY camera modules without the hassle of configuring them so he made one that looks like an access point and starts streaming as soon as you connect to it.[GitHub]

The code he provides allows the ESP32 to appear as an Open Access Point which you can connect to from a PC or smartphone. The awesome sauce here is that the ESP32 resolves all DNS requests to a redirect in a similar manner to what happens when someone connects to an open Wi-Fi access point in a mall, Instead of a captive portal page that asks the user to authenticate or accept terms and conditions, [Daniel Padilla]’s code instead redirects to the streaming page et voila! Instant camera stream, and it is that simple.

We love this project because it is an elegant way to solve a problem, and it also teaches newbies about captive portals and their implementation. We covered a cheap ESP32 Webcam in the past and this project also comes with code for you to get started. We would love to see what you come up with next.

This Clapperboard Prints Movie Posters

June 10, 2019 by Rich Hawkes 3 Comments

The clapperboard is a device used in video to synchronize audio and video. Its role in movies is well known and its use goes back in one form or another to the 1920s. [Gocivici] is a big movie fan and created a clapperboard that is able to print out posters of recently announced movies when the clapper is clapped.

The poster is not a big, full color job, but rather a black and white one, roughly the size of a movie ticket. [Gocivici] keeps his movie tickets in a journal and wanted to be able to keep small posters in there along with them. A thermal printer is used to print the poster along with the title, the release date, and some information about the movie. In addition to the printer, the hardware involved is a Raspberry Pi, a switch, and an LED. The clapperboard itself is 3d printed and then painted. A bit of metal is used to keep the clappers apart and give a bit of resistance when pressing them together. A nice touch is a metal front, so you can use magnets to keep your posters on the board.

[Gocivici] has detailed build instructions up along with a video (available after the break) showing the printer in action. The 3d models are available as well as the code used to create the posters after grabbing data from TMDb. If you need your clapperboard to be as accurate as possible, take a look at this atomic clock clapperboard.

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Repurposed Plastic Protects PCBs

June 6, 2019 by Brian McEvoy 28 Comments

An errant wire snipping across the wrong electrical pins spells the release of your magic smoke. Even if you are lucky, stray parts are the root of boundless malfunctions from disruptive to deadly. [TheRainHarvester] shares his trick for covering an Arduino Nano with some scrap plastic most of us have sitting in the recycling bin. The video is also after the break. He calls this potting, but we would argue it is a custom-made cover.

The hack is to cut a bit of plastic from food container lids, often HDPE or plastic #2. Trim a piece of it a tad larger than your unprotected board, and find a way to hold it in place so you can blast it with a heat gun. When we try this at one of our Hackaday remote labs and apply a dab of hot glue between the board and some green plastic it works well. The video suggests a metal jig which would be logical when making more than one. YouTube commenter and tip submitter [Keith o] suggests a vacuum former for a tighter fit, and we wouldn’t mind seeing custom window cutouts for access to critical board segments such as DIP switches or trimmers.

We understand why shorted wires are a problem, especially when you daisy-chain three power supplies as happened in one of [TheRainHarvester]’s previous videos.

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Tokyo Mechanical Keyboard Meetup Knocks Our Clacks Off

June 5, 2019 by Kerry Scharfglass 7 Comments

Just a few days ago, on the other side of the planet from this author, there was a mechanical keyboard meetup in Tokyo. Fortunately through the magic of the Internet we can all enjoy the impressive collection of devices people brought, and boy were there some interesting specimens. There were certainly the inevitable collections of strange artisan keycaps, unusual handmade switches, and keycap sets only available in one group buy five years ago in Nicaragua. But among the bright colors were some truly unique custom designs the likes of which we haven’t see before. A single source is hard to credit, you could check the hashtag #tokyomk6 on Twitter, or [obra]’s thread of photos, or this great blog post (video walkthroughs and photos included) from [romly].

Speaking of [romly], one of their designs stands out as particularly unusual. There are a few things to note here. One is the very conspicuous surface profile of the (clearly totally custom) keycaps themselves. Instead of flat or cylindrical or spherical, these are round. Round like the outside of a log. If we didn’t know better it might look like the entire thing was sculpted or extruded as a single unit. And just below the deck are the perpendicular thumb clusters. Frankly we aren’t sure how to refer to this design feature. The switches are mounted at right angles facing inward so the user places a thumb inside it in a style reminiscent of the DataHand. It’s quite interesting, and we’d be love to know more about what specific functionality it provides.

Another interesting entrant is this keyboard with unusually staggered switches and hexagonal caps (check out the individual markings!). Very broadly there are two typical keyboard layout styles; the diagonal columns of QWERTY (derived from a typewriter in the 1800’s) or the non slanted columns of an “ortholinear” or matrix style layout. By those metrics this is something like an ortholinear keyboard in that its switches overlap their neighbors by half, but the edge to edge close packed caps imply that it might be something else. We’d be very interested to know how typing on this beast would be!

There were so many more awesome designs present at the meetup that this would never end if we tried to document them all. Take a look through the posts and call out anything else too excellent to go unnoticed!

Thanks [obra] for Tweeting about this so we could discover it.

C.H.I.P. Or Z.O.M.B.I.E? We Can’t Decide

June 4, 2019 by Jenny List 58 Comments

Imagine for a moment that you are back in 2015. Radio Shack are going to the wall, Heathkit returning from the dead, and Arduino spliting into two warring Arduinos. And someone has announced a tiny Linux-capable microprocessor board called the C.H.I.P. that will cost only $9. We all thought that last one was pretty cool at the time, didn’t we. Then Heathkit’s new products turned out to be pretty lacklustre, the warring Arduinos merged, and the C.H.I.P? The consensus was that $9 was a tall order for that BoM at the time, and then the Raspberry Pi people gave away a free Pi Zero on the front of a magazine before selling it for £5 ($6.30). It didn’t matter that the C.H.I.P. had a nifty all-in-one screen and keyboard combo called the Pocket C.H.I.P. which was a significant object of desire, the venture lasted for three years before finally hitting the rocks last year.

Now the C.H.I.P. is back, in a crowdfunding campaign fronted by one of its original engineers. It’s been renamed the Popcorn, and it comes in three variants. The Original Popcorn is a compatible C.H.I.P. by any other name, while the Super Popcorn is a much higher-spec machine that comes in quad and octacore variants with AmiLogic SoCs. All three have 32 GB eMMC on board, and the specs are suitably impressive but not out of the ordinary for a 2019 single board computer. Prices are $49, $69, and $89, which takes away that optimistic $9 price tag that made the original so attractive. There is no Pocket C.H.I.P. which is a shame because for us that was the only reason to buy a C.H.I.P, but there is a companion board called the Stovetop that provides Raspberry Pi-style desktop and display interfaces.

We wish them well, but it’s difficult to escape the conclusion that the hardware world has moved on and the window of opportunity has closed. It’s not that these boards are not good ones, more that they now join a plethora of others which come a lot closer to the low price of the original. Still, there remains a C.H.I.P. community still out there, so perhaps that will save the day for them.

We interviewed the C.H.I.P.’s creators back in 2015, and marked its passing last year.

Thanks [Rose] for the tip.

Tearing Apart Pulse Transformer Switches

June 3, 2019 by Brian Benchoff 29 Comments

If you like mechanical keyboards, you like switches. Historically, switches were weird, with strange capacitive rubber dome switches in Topre boards, buckling springs in the IBM Model M, and beamsprings in earlier IBM keyboards. This teardown of an HP signal generator has the weirdest keyboard switches ever. They’re being called pulse transformer switches, but they are the strangest, weirdest, and most complicated keyboard switch we’ve ever seen

Mechanically, these keys are mounted on a 1×5 plastic frame with a plunger that presses down on a (brass?) photoetched plate. Mechanically, this is effectively a metal dome keyboard that simply presses a springy bit of metal against a contact on a printed circuit board. That’s the mechanical explanation, the electrical theory of operation is much, much weirder.

Electrically, this keyboard consists of a printed circuit board with two coils underneath each key. The circuit is wired up so two keys are ‘read’ at the same time with a pulse from a multiplexer. This pulse induces a current in the ‘sense’ coil of two individual keys which is sent to a comparator. If both keys are not pressed, the comparator sees a positive and a negative voltage which cancels out, meaning no keys are pressed. If one key is pressed, the metal dome shorts out the transformer underneath the keyboard, meaning only one voltage is seen by the comparator, and that key is registered as being pressed.

This is some crazy keyboard circuitry, and I do not say that lightly. There are ‘acoustic’ keyboards out there which consist of a row of keys striking a metal bar with an acoustic transducer on each end. By measuring the time it takes for the sound of a keypress to reach either end of the metal bar, a keypress can be registered. This is weird and expensive to build, and it’s still simpler than a pulse transformer switch. Check out the video below.

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