A purple PCB with an OLED display and various chips

A Neat Little Tool To Reset The Fuses On Your ATtiny

April 16, 2022 by Robin Kearey 8 Comments

If you’re an experienced hacker, you’ve probably run into a problem at some point and thought “let’s make a tool to automate that”. A few hours later you’ve got your tool, but then realize that the amount of work you put into making the tool vastly exceeds what you would have needed to solve the original problem manually. That really doesn’t matter though: developing a fancy tool can be a rewarding experience that teaches you way more about the original problem than you would have learned otherwise. [sjm4306]’s ATtiny High Voltage Fuse Reset-er is a clever device that firmly falls into this category.

The problem it solves is familiar to anyone who’s ever worked with Atmel/Microchip’s ATtiny series of microcontrollers: set one of the configuration fuses incorrectly and you’re no longer able to reprogram your chip. Getting the ATtiny back to its original configuration requires a high-voltage programming step that involves pulling the reset pin to 12 V in what’s otherwise a 5 V system. You could simply grab a spare 12 V supply and hack together a level shifter with a few transistors, but where’s the fun in that?

[sjm4306]’s solution is built on a pretty purple PCB that contains an ATmega328, an OLED display, and sockets to accommodate various versions of the ATtiny series microcontrollers. To generate the required 12 V, one could simply use an off-the-shelf boost converter IC. But instead, he decided it would be interesting to make such a circuit out of discrete components and control it using the ATmega. After all, this chip already contains timers to generate PWM signals and an ADC to measure the converter’s output voltage, so all it took was to write some control logic in the form of a PID controller.

The end result, as you can see in the video embedded below, is a convenient little PCB that runs off a 5 V USB power supply and resets the fuses on your ATtiny at the push of a button. Sometimes, simple tools that do one thing well are all you need; however, if you’re looking for an all-in-one AVR programmer that also supports HV programming, check out this AVR Multi-Tool.

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RSS Printer Gives You The Hard Copy News You Desire

April 16, 2022 by Lewin Day 23 Comments

The days of yore saw telex machines and dot-matrix printers with continuous feed paper churning out data in hardcopy form in offices around the world. [Jan Derogee] wanted a bit of that old-school charm, and set about building a RSS news printer using a venerable old printer in his possession.

The build relies on an ESP8266, with the WiFi-enabled microcontroller readily capable of jumping online and querying RSS feeds for content. It scrapes the XML files for title, description, and publication date information, and formats this for output to the printer. The microcontroller then spits out the data over a Commodore serial interface to a Brother HR-5C printer. Unlike dot-matrix printers of its contemporary era, the HR-5C is a thermal printer. Once loaded up with a roll of the appropriate paper, it can print continuously without requiring any hard-to-source ink ribbons.

Armed with a continuous supply of wireless internet and 210 mm rolls of thermal printer paper, [Jan]’s system should provide news summaries to him for years to come. We’ve seen similar retro news ticker projects before, too. Video after the break.

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Can You Help Solve The Mystery Of This 1930s TV?

April 16, 2022 by Jenny List 23 Comments

84 years ago, a teenager built a TV set in a basement in Hammond, Indiana. The teen was a radio amateur, [John Anderson W9YEI], and since it was the late 1930s the set was a unique build — one of very few in existence built to catch one of the first experimental TV transmitters on air at the time, W9XZV in Chicago. We know about it because of its mention in a 1973 talk radio show, and because that gave a tantalizing description it’s caught the interest of [Bill Meara, N2CQR]. He’s tracking down whatever details he can find through a series of blog posts, and though he’s found a lot of fascinating stuff about early TV sets he’s making a plea for more. Any TV set in the late ’30s was worthy of note, so is there anyone else out there who has a story about this one?

The set itself was described as an aluminium chassis with a tiny 1″ CRT, something which for a 1930s experimenter would have been an expensive and exotic part. He’s found details of a contemporary set published in a magazine, and looking at its circuit diagram we were immediately struck by how relatively simple the circuit of an electrostatically-deflected TV is. Its tuned radio frequency (TRF) radio front end is definitely archaic, but something that probably made some sense in 1939 when there was only a single channel to be received. We hope that [Bill] manages to turn up more information.

We’ve covered some early TV work here not so long ago, but if you fancy a go yourself it’s not yet too late to join the party.

IoT Pool Monitor Helps You Keep It Crystal Clear

April 16, 2022 by Lewin Day 5 Comments

Having a pool is great, but it also requires significant monitoring and maintenance to keep it crystal clear and clean. The OPNpool controller from [Coert Vonk] aims to help in this task, integrating neatly into the smart home ecosystem of today.

OPNpool runs on an ESP32, and is capable of monitoring pool controllers, pumps, and chlorinators, as well as working with thermostats and other hardware to control the state of the pool. This allows the system to do useful things like run high-powered pumps when electricity is cheapest, or to find the best timing to run heating circuits. The controller relies on MQTT messaging and can integrate with Home Assistant for those that prefer to run their own cloud-independent smart home systems.

With WiFi onboard the ESP32, there’s no need for a hardwired LAN connection, and the system can be administered remotely over the web. It’s also capable of talking with other hardware over RS-485 and bringing it under its own control. With OPNpool installed, monitoring pool conditions can be done from the leisure of one’s deck chair with a smartphone, rather than squinting and dark LCDs in equipment cabinets.

It’s a useful tool that could be just the ticket for the savvy, IoT-aware pool owner. We’ve seen other DIY pool controllers before, too. With summer just around the corner, it’s the perfect time to get hacking!

Easy, Extensible, Open

April 16, 2022 by Elliot Williams 16 Comments

I’m a huge DIY’er. I don’t like to buy things when I can build them myself. But honestly, that doesn’t always end up in the optimal allocation of my time, when viewed from a getting-stuff-done perspective. Sometimes, if you’ve got a bigger project in mind, the right way is the quick way, and the quick way is buying something that already works. But when that something is itself not hackable, you’d better be darn sure that it does what you need, and what you could reasonably expect to need in the future, out of the box. And that’s where extensibility comes in.

It’s rare to find products out there that are designed to be both easy to use for the newbie, but extensible for the advanced user. For one, it’s hard work to tick either one of these boxes alone, so it’s twice as hard to nail both. But my other sinking suspicion is that designers tend to have an end user in mind, and maybe only one end user, and that’s the problem. When designing for the newbie, convenience is king. Or if targeting the pro, you maximize flexibility, but perhaps at the expense of designed-in complexity.

There’s a way out, a cheat code, if you will. And that’s making the project open source. Go ahead and hide the complexity from the new user if you want — as long as the pro is able to dive into the schematics or the source code, she’ll figure out how to extend it herself. Openness frees the designers up to worry about making it easy to use, without compromising its flexibility.

I think that this blend of easy and extensible, through openness, is what fundamentally drove the success of Arduino. On the surface layer, there are libraries that just do what you want and drop-down menus with examples to access them. But when you needed to actually use the chip’s hardware peripherals directly, there was nothing stopping you. For the community at large, the fact that all of the code was openly available meant that extending the base was easy — and let’s not beat around the bush, the community’s libraries, tutorials, and example projects are the real reason for the success of the platform.

Look around you, and look out when you’re making that next non-DIY shortcut purchase. Is it easy to use? Can you make it do the things that it doesn’t yet do? Just two simple requirements, yet they seem to knock out so many products if you want both. Then look at those that are both simple and flexible — are they also open? At least in my little world, the answer is almost always “yes”.

Tiny Pneumatic Tool Made From A Single(-ish) Bolt

April 16, 2022 by Dan Maloney 17 Comments

We’ve noticed a couple of things about the “Widget from a Single Bolt” genre of metalworking videos. The first thing is that almost all of them need to use a freakishly large bolt, and many of them also rely on other materials to complete the build. And secondly, these builds all pretty much depend on a lathe to transform the bolt into the intended widget.

While this single-bolt pneumatic graving tool build is guilty on that first count, it somehow manages to avoid needing a lathe. Not that [AMbros Custom] wouldn’t have greatly benefited from a lathe to make this somewhat specialized and unusual tool a reality. A graving tool or graver is used during metal engraving, the art of making controlled cuts into flat metal surfaces to render complicated designs. A powered graver like this can make engraving faster and more precise than a traditional manual graver, which is typically powered by light taps with a special hammer.

The lathe-less build [AMbros] undertook was quite ambitious given the number of moving parts and the tight tolerances needed for a pneumatic tool. The real hero here is the hand drill pressed into service as an impromptu lathe; teamed with various tools from files to emery cloth to even a Dremel and an angle grinder, it did a respectable job turning down the various parts. The entire build is shown in the video below, and it’s worth a watch just to see what ingenuity can accomplish when coupled with sheer persistence.

Hats off to [AMbros] for sticking with what was admittedly a problematic build, and here’s hoping a lathe is in his future. With that, he may be able to pull off other impressive “single-bolt” builds, like this combination padlock. Or throw another bolt or two in and pull off this cryptex-like safe.

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Paper Tape Reader Self-calibrates, Speaks USB

April 16, 2022 by Donald Papp 22 Comments

Input devices consisting of optical readers for punched paper tape have been around since the earliest days of computing, so why stop now? [Jürgen]’s Paper Tape Reader project connects to any modern computer over USB, acting like a serial communications device. Thanks to the device’s automatic calibration, it works with a variety of paper materials. As for reading speed, it’s pretty much only limited to how fast one can pull tape through without damaging it.

Stacked 1.6 mm PCBs act as an enclosure, of sorts.

While [Jürgen]’s device uses LEDs and phototransistors to detect the presence or absence of punched holes, it doesn’t rely on hardware calibration. Instead, the device takes analog readings of each phototransistor, and uses software-adjusted thresholds to differentiate ones from zeros. This allows it to easily deal with a wide variety of tape types and colors, even working with translucent materials. Reading 500 characters per second isn’t a problem if the device has had a chance to calibrate.

Interested in making your own? The build section of the project has all the design files; it uses only through-hole components, and since the device is constructed from a stack of 1.6 mm thick PCBs, there’s no separate enclosure needed.

Paper tape and readers have a certain charm to them. Cyphercon 4.0 badges featured tape readers, and we’ve even seen the unusual approach of encoding an I²C byte stream directly onto tape.