Repairing A Vintage Sharp MemoWriter

As you may know, we’re rather big fans of building things here at Hackaday. But we’re also quite partial to repairing things which might otherwise end up in a landfill. Especially when those things happen to be interesting pieces of vintage hardware. So the work [ekriirke] put in to get this early 1980’s era Sharp MemoWriter EL-7000 back up and running is definitely right up our alley.

There were a number of issues with the MemoWriter that needed addressing before all was said and done, but none more serious than the NiCd batteries popping inside the case. Battery leakage is a failure mode that most of us have probably seen more than a few times, but it never makes it any less painful to see that green corrosion spreading over the internals like a virus. When [ekriirke] cracked open this gadget he was greeted with a particularly bad case, with a large chunk of the PCB traces eaten away.

The corrosion was removed with oxalic acid, which dropped the nastiness factor considerably, but didn’t do much to get the calculator back in working order. For that, [ekriirke] reconnected each damaged trace using a piece of wire; he even followed the original traces as closely as possible so the final result looked a little neater. Once everything was electrically solid again, he covered the whole repair with a layer of nail polish to adhere the wires and add a protective coating. Nail polish might not have been our first choice for a sealer, and likely not that particular shade even if it was, but sometimes you’ve got to use what you have on hand.

After years of disuse the ribbon cartridge was predictably dry, so [ekriirke] rejuvenated it with the fluid from a permanent marker applied to the internal sponge. He also made some modifications to the battery compartment so he could insert rechargeable Ni-MH AA batteries rather than building a dedicated pack. There’s no battery door in the enclosure, so removing the batteries will require opening the calculator up, but at least he has the ability to remove the batteries before putting the device in storage. Should help avoid a repeat of what happened the first time.

If you’re a fan of a good restoration, we’ve got plenty to keep you entertained. From bringing a destroyed Atari back from the dead to giving some cherished children’s toys a new lease on life, fixing old stuff can be just as engrossing as building it from scratch.

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A Tiny Sharp MZ-80K That Really Works!

If you were a computer enthusiast in the late 1970s and early 1980s, one of your objects of desire may well have been a Sharp MZ-80K. This was an all-in-one machine from the Japanese electronics giant, and like Commodore’s PET line it included a CRT monitor, full alphanumeric keyboard and cassette tape drive in a smart console.

[Yasushi Enari] is a modeller of miniatures, and while at high school back in 1981 he made a perfect 1/5 scale model of an MZ-80K as an art project. Fast-forward to 2017, and with the help of a Raspberry Pi Zero, a miniature LCD composite video screen, and a Li-Po battery, he’s turned his 1981 model into a functioning computer.

Sadly he was not able to make his tiny 1981 plastic keyboard work, so an external Bluetooth unit is required to perform that function. And he makes no mention of running an MZ-80K emulator on the little machine, either. But the result is a work of art, and an odd collaboration between his adult and teenage self, something we are guessing most readers would be proud to own.

This isn’t the first tiny replica computer we’ve shown you, an Odroid W went into making this tiny Powermac from an American Girl doll’s toy computer.

Thanks [RC2014] for the tip.

How To Sharpen Your Woodworking Tools On A Budget

Wood may seem like a soft, weak material if you’re used to working with steel, but to do good work, you’ll quickly learn you need your tools sharp. Buying and maintaining a good set of tools can be expensive for the home gamer, so [shopbuilt] put together an Instructable on how to sharpen your woodworking tools on a budget.

The trick is to use sandpaper. It’s a good quality abrasive material and is readily available. You’ll want a selection of different grits – low grits to get started, higher grits when finishing. The reason this is cheaper is that you can get a selection of 5-10 different sandpapers for under $20. Getting even a couple of decent sharpening stones wouldn’t be possible at that price. In the long run, they’ll last longer but this is a budget option we’re talking about.

Obviously you can’t just sharpen something with sandpaper – [shopbuilt] suggests mounting the paper to the flattest surface you can find. The use of a tempered glass panel from a fridge shelf is, in our mind, an inspired choice here. 3D printer enthusiasts have been using similar techniques for heated beds for the best part of a decade now.

We love woodworking here at Hackaday, so get your feet wet with these woodworking basics for the hardware hacker.

Hackaday Links: April 3, 2016

April Fool’s Day was last Friday, and the Internet was garbage for a day. Our April Fool’s prank was amazing, and in a single day garnered more views than the Raspberry Pi 3 launch announcement from a month prior. There just might be a market here for Apple. Here’s a short roundup of some of the best electronics April Fool’s posts:

This, surprisingly, was not an April Fool’s post. [Dave Jones] has been looking to upgrade his workspace for a few years now. He’s finally found a place. It’s the old Altium office in Sydney. [Dave] worked at Altium before spinning up the EEVblog, so this really is his old stomping grounds. It’s 4000 square meters (43,000 square feet), and exactly 3950 square meters larger than his current lab. What is he going to do with all that space? He’s looking for suggestions, but I would suggest an awesome model train layout. A [Dave Haynie]-style tour would also be acceptable.

Yesterday was the unofficial geekhack / deskthority / r/mechanicalkeyboards SoCal Mechanical Keyboard meetup at Datamancer in Montclair, CA. I was there, got a Control key to replace the Caps Lock key on my Novatouch, and took a lot of pictures.

It’s a presidential election year in the US, and that means millions of people are going to make America great again by polluting their front yard with campaign signs. These campaign signs are usually made out of coroplast, a material that looks like corrugated cardboard, but is made out of dead dinosaurs instead of dead trees. Coroplast is a very interesting material, and [uminded] tipped us off to some guy that makes mini speedboats in this rather uncommon material.

There are some things you just shouldn’t do. Combining octocopters with chainsaws, for example. You shouldn’t do it, but someone will anyway, and YouTube exists. Here’s an octocopter with a chainsaw.

Foxconn is buying Sharp. Sharp has a rather large portfolio of LEDs and optoelectronics, but this deal is mostly for Sharp’s large contract manufacturing business.

Proximity Switch For Your Mains Devices

[Ivan’s] friend built a proximity sensor to switch his LED bench lighting off every time he walked away. The idea is pretty neat, so [Ivan] decided to implement it for mains devices by making this proximity switched outlet box.

A Sharp GP2D12 infrared distance sensor is the key to the system. It has an emitter and receiver that combine to give distance feedback base on how much of the light is reflected back to the detector. This is presented as a voltage curve which is monitored by an ATtiny85 (running the Arduino bootloader). It is small enough to fit inside the outlet box along with a tiny transformer and linear regulator to power to logic circuitry. The mains are switched with a relay using an NPN transistor to protect the chip’s I/O pins.

Check out the video after the break to see this in action. It should be a snap to add a count-down timer that gives you a bit more freedom to move around the workshop. With that in place this is a fantastic alternative to some other auto-shutoff techniques for your bench outlets.

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Up Your FPGA Game By Learning From This LCD Control Prototype

[Cesar] recently got a PSP display up and running with his FPGA development board. That’s a nice project, but what we really like is that he set aside a lot of time to show how it’s done every step of the way. This isn’t just a tutorial on that particular screen, but an overview of the skill set needed to get any piece of hardware working.

The screen itself is a Sharp LQ043T3DX02; a 480×272 TFT display with 16 million colors. Not bad for your project but when you start looking into the control scheme this isn’t going to be like using a Nokia screen with an Arduino. It takes twenty pins to control it; Red, green, and blue take sixteen pins, four pins are used for control, the rest are CK, DISP, Hsync, Vsync.

Wisely, [Cesar] designs his own interface board which includes the connector for the ribbon cable. It also has drivers for the screen’s backlight and supplies power to the device. With hardware setup complete he digs into the datasheets. We just love it that he details how to get the information you’re looking for out of this document, and shows his method of turning that first into a flow chart and then into code for the FPGA.