Reviving An Electron Microscope With Arduino

April 7, 2018 by Tom Nardi 20 Comments

We don’t know about you, but when our friends ask us if we want to help them fix something, they’re usually talking about their computer, phone, or car. So far it’s never been about helping them rebuild an old electron microscope. But that’s exactly the request [Benjamin Blundell] got when a friend from a local hackerspace asked if he could take a look at a vintage Cambridge Stereoscan 200 they had found abandoned in a shed. Clearly we’re hanging out with the wrong group of people.

As you might imagine, the microscope was in desperate need of some love after spending time in considerably less than ideal conditions. While some of the hackerspace members started tackling the hardware side of the machine, [Benjamin] was tasked with finding a way to recover the contents of the scope’s ROM. While he’s still working on verification, the dumps he’s made so far of the various ROMs living inside the Stereoscan 200 have been promising and he believes he’s on the right track.

The microscope uses a mix of Texas Instruments 25L32 and 2516 chips, which [Benjamin] had to carefully pry out after making sure to document everything so he knew what went where. A few of the chips weren’t keen on being pulled from their home of 30-odd years, so there were a few broken pins, but on the whole the operation was a success.

Each chip was placed in a breadboard and wired up to an Arduino Mega, as it has enough digital pins to connect without needing a shift register. With the wiring fairly straightforward, [Benjamin] just needed to write up some code to read the contents of the chip, which he has graciously provided anyone else who might be working on a similar project. At this point he hasn’t found anything identifiable in his ROM dumps to prove that they’ve been made successfully, all he really knows right now is that he has something. At least it’s a start.

More and more of these older electron microscopes are getting a second lease on life thanks to dedicated hackers in their home labs. Makes you wonder if there’s ever going to be a piece of hardware the hacker community won’t bend to their will.

Magic 8 Ball Business Card Will Answer All Your Questions

April 5, 2018 by Lewin Day 14 Comments

The PCB business card has long been a staple amongst the freelance EE set. It’s a way to show potential clients that you can do the job, as well as leave a great first impression. Some are simple blinkenlights devices, others have contact information on USB storage. We reckon that [Seamus] has really hit it out of the park with this one, though.

That’s right- this business card riffs on the classic Magic 8-ball toy. Ask a question, shake the card, and it’ll light an LED with the corresponding answer to your query. Use it as a desk toy, or break deadlocks in meetings by looking to the card for the correct course of action.

It’s a very tasteful build, showing off [Seamus]’s minimalist chops – consisting of just a decade counter, a tilt sensor, and some LEDs. When the card is shaken, the tilt sensor outputs a series of pulses to the clock line of the decade counter, whose outputs are the 8 LEDs. When the tilt sensor settles, it lands on the final answer.

We think it’s a great card, which shows off both fundamental technical skills as well as a certain flair and creativity which can be key to landing exciting projects. It doesn’t hurt that it’s good fun, to boot. For another take on the Magic 8-ball, check out this build that can give you a Yes/No answer on demand.

3D Print A Thinner Car Key

April 4, 2018 by Lewin Day 30 Comments

Almost all modern cars come with keyless entry, some even come with keyless start. Of course, the price you pay for this technology is a bulky plastic keyfob that is an absolute pain to remove from your pockets, and generally spoils the lines of your carefully chosen outfit. [Jeremy] decided enough was enough.

The project begins with a careful disassembly of the original key. This is important to avoid damaging the PCB inside, particularly if there are any delicate wire links between different sections of the keyfob. With the piece disassembled, it was then time to start designing a replacement encasement to hasten escapement while pacing the pavement.

The 3D printer really is the perfect tool for the job here, and [Jeremy] employs it well. With this being a proximity-based keyfob, the buttons are only necessary if you want to operate the locks at a distance. They simply took up too much vertical space, so they had to go. In the end, with a redesigned housing for the PCB, and while retaining the backup mechanical key, the new fob is just 11mm, down from 18mm – a nearly 40% saving in thickness!

It’s a tidy way to clean up your pockets and make life easier. We’ve seen similar work before, too.

Pepper Mill Locks Your Door

April 2, 2018 by Lewin Day 17 Comments

Pepper! If you’ve ever tried to grind it, you’ve probably noticed it takes a bit of elbow grease. It’s actually possible to source electric pepper mills to grind it for you, in fact. It just so happens that [MarioM66] had one to hand, and a door lock that needed automating.

Seeing as grinding pepper requires at least as much torque as turning an average key in an average lock, the electric pepper mill makes perfect sense to use as a lock actuator. This build actually uses the electric pepper mill to directly turn the key in the lock, courtesy of an adapter to couple the square output shaft to the key. The adapter was crafted out of a moldable plastic called MultiMorph. The pepper mill is being used for its high-torque motor & gearbox, which makes it absolutely perfect for this application.

The rest of the project leans heavily on the hacker’s go-to, an Arduino and some off-the-shelf gesture recognition modules. Now, it’s possible to lock and unlock the door at the press of a button or the wave of a hand! Video after the break.

It’s great to see run-of-the-mill objects hacked into useful parts for new projects. In the same vein, check out this car that lets you fistbump to unlock.

Continue reading “Pepper Mill Locks Your Door” →

Reverse Engineering Bottle Threads For Fun And Profit

April 1, 2018 by Kristina Panos 37 Comments

Recently, one of [Eric]’s clients asked him to design a bottle. Simple enough for a product designer, except that the client needed it to thread into a specific type of cap. And no, they don’t know the specs.

But that’s no problem, thought [Eric] as he turned on the exhaust fan and reached for the secret ingredient that would make casting the negative image of the threads a breeze. He mixed up the foul-smelling body filler with the requisite hardener and some lovely cyan toner powder and packed it into the cap with a tongue depressor. Then he capped off the cast by adding a small PVC collar to lengthen the cast so he has something to grab on to when it’s time to take it out.

Bondo does seem like a good choice for casting threads. You need something workable enough to twist out of there without breaking, but rigid enough that the small detail of the threads isn’t lost. For the release agent, [Eric] used Johnson’s Paste Wax. He notes from experience that it works particularly well with Bondo, and even seems to help it cure.

Once the Bondo hardened, [Eric] made sure it screwed in and out of the cap and then moved on to CAD modeling and 3D printing bottle prototypes until he was satisfied. We’ve got the video screwed in after the break to cap things off.

Did you know that you can also use toner powder to tint your epoxy resin? Just remember that it is particulate matter, and take precautions.

Continue reading “Reverse Engineering Bottle Threads For Fun And Profit” →

An 8-Bit ALU, Entirely From NAND Gates

March 31, 2018 by Jenny List 18 Comments

One of the things that every student of digital electronics learns, is that every single logic function can be made from a combination of NAND gates. But nobody is foolhardy enough to give it a try, after all that would require a truly huge number of gates!

Someone evidently forgot to tell [Notbookies], for he has made a complete 8-bit ALU using only 4011B quad NAND gates on a set of breadboards, and in doing so has created a minor masterpiece with his wiring. It’s inspired by a series of videos from [Ben Eater] describing the construction of a computer with the so-called SAP (Simple As Possible) architecture. The 48 4011B DIP packages sit upon 8 standard breadboards, with an extra one for a set of DIP switches and LEDs, and a set of power busbar breadboards up their sides. He leaves us with the advice borne of bitter experience: “Unless your goal is building a NAND-only computer, pick the best IC for the job“.

We have covered countless processors and processor components manufactured from discrete logic chips over the years, though this makes them no less impressive a feat. The NedoNAND has been a recent example, a modular PCB-based design. TTL and CMOS logic chips made their debut over 50 years ago so you might expect there to be nothing new from that direction, however we expect this to be well of projects that will keep flowing for may years more.

Via /r/electronics/.

Build Your Own Antenna For Outdoor Monitoring With LoRa

March 31, 2018 by Christopher Wang 15 Comments

LoRa and LPWANs (Low Power Wide Area Networks) are all the range (tee-hee!) in wireless these days. LoRa is a sub 1-GHz wireless technology using sophisticated signal processing and modulation techniques to achieve long-range communications.

With that simplified introduction, [Omkar Joglekar] designed his own LoRa node used for outdoor sensor monitoring based on the HopeRF RFM95 LoRa module. It’s housed in an IP68 weatherproof enclosure and features an antenna that was built from scratch using repurposed copper rods. He wrote up the complete build, materials, and description which makes it possible for others to try their hand at putting together their own complete LoRa node for outdoor monitoring applications.

Once it’s built, you can use this simple method to range test your nodes and if you get really good, you might be setting distance records like this.