An Instant Camera Using E-Paper As Film

February 10, 2023 by Jenny List 16 Comments

The original Polaroid cameras were a huge hit not just for their instant delivery, but for the convenient size of the permanent images they delivered. It’s something that digital cameras haven’t been able to replicate, which drew [Cameron] to produce a modern alternative. In the place of the chemical film of the original, it uses a removable e-paper display in a frame. The image is stored in the pixels of the e-paper, which can be kept as a digital version of the photograph until reattached and replaced with another freshly taken picture.

At its heart is an ESP32 with a camera, and the “film” is a Waveshare NFC e-paper module. The device is 3D printed, and manages a very creditable early-1970s aesthetic redolent of the more upmarket Polaroids of the day. Using it is as simple as pressing the button and deciding whether you like what’s on the screen. You can see it in action in the video below the break.

We like his project for its aesthetics, as well as for the very idea of using e-paper as a medium. There’s also something to be said for not having to put a Polaroid print in a clip under your armpit while it develops. Meanwhile if you do hanker for the real thing, it’s a subject we’ve looked at in the past.

Continue reading “An Instant Camera Using E-Paper As Film” →

Reverse Engineering British Rail Tickets

February 9, 2023 by Jenny List 21 Comments

There was a time when to take a British rail journey was to receive a ticket barely changed since Victorian times — a small cardboard rectangle printed with the destination through which the inspector on the train would punch a hole. In recent decades these were replaced by credit-card-sized thin card, and now increasingly with scanable 2D codes from an app. These caught the attention of [eta], and she set about reverse engineering their operation.

The codes themselves are Aztec barcodes, similar to a QR code but with a single central fiducial mark. At first glance they resemble the codes used by non-UK ticketing systems, but she soon found out that they don’t follow the same standard. There followed a lengthy but fascinating trail of investigation, involving app decompilation of a dodgy copy of the ticket inspector app to find public keys, and then some work with a more reputably sourced app from another ticketing company.

Along the way it revealed a surprising amount of traveler data that maybe shouldn’t be in the public domain, and raises the question as to why the ticketing standard remains proprietary. It’s well worth a read.

If you’d like more UK rail ticket hacking, it formed the subject of a talk at EMF 2022.

Ask Hackaday: The Ten Dollar Digital Mixing Desk?

February 6, 2023 by Jenny List 110 Comments

There comes a point in every engineer’s life at which they need a mixing desk, and for me that point is now. But the marketplace for a cheap small mixer just ain’t what it used to be. Where once there were bedroom musicians with a four-track cassette recorder if they were lucky, now everything’s on the computer. Lay down as many tracks as you like, edit and post-process them digitally without much need for a physical mixer, isn’t it great to be living in the future!

This means that those bedroom musicians no longer need cheap mixers, so the models I was looking for have disappeared. In their place are models aimed at podcasters and DJs. If I want a bunch of silly digital effects or a two-channel desk with a crossfader I can fill my boots, but for a conventional mixer I have to look somewhat upmarket. Around the three figure mark are several models, but I am both a cheapskate and an engineer. Surely I can come up with an alternative. Continue reading “Ask Hackaday: The Ten Dollar Digital Mixing Desk?” →

End Of An Automation Era As Twitter Closes Its Doors To Free API Access

February 3, 2023 by Jenny List 40 Comments

Over the last few months since Elon Musk bought Twitter there has been a lot of comment and reaction, but not much with relevance to Hackaday readers. Today though that has changed, with an announcement from the company that as of February 9th they will end their free API tier. It’s of relevance here because Twitter has become one of those glue items for connected projects and has appeared in many featured works on this site. A week’s notice of a service termination is exceptionally short, so expect to see a lot of the Twitter bots you follow disappearing.

Twitter bot owners have the option of paying to continue with Twitter, or rebuilding their service to use a Mastodon instance such as botsin.space. If the fediverse is new to you, then the web is not short of tutorials on how to do this.

We feel that Twitter will be a poorer place without some of the creative, funny, or interesting bots which have enriched our lives over the years, and we hope that the spam bots don’t remain by paying for API access. We can’t help feeling that this is a misguided step though, because when content is the hook to bring in the users who are the product, throwing out an entire category of content seems short-sighted. We’re not so sure about it as a move towards profitability either, because the payback from a successful social media company is never profit but influence. In short: social media companies don’t make money but the conversation itself, and that can sometimes be worth more than money if you can avoid making a mess of it.

If the bots from our field depart for Mastodon, we look forward to seeing whether the new platform offers any new possibilities. Meanwhile if your projects don’t Toot yet, find out how an ESP32 can do it.

Header: D J Shin, CC BY-SA 3.0.

Now ChatGPT Can Make Breakfast For Me

February 2, 2023 by Jenny List 62 Comments

The world is abuzz with tales of the ChatGPT AI chatbot, and how it can do everything, except perhaps make the tea. It seems it can write code, which is pretty cool, so if it can’t make the tea as such, can it make the things I need to make some tea? I woke up this morning, and after lying in bed checking Hackaday I wandered downstairs to find some breakfast. But disaster! Some burglars had broken in and stolen all my kitchen utensils! All I have is my 3D printer and laptop, which curiously have little value to thieves compared to a set of slightly chipped crockery. What am I to do!

Never Come Between A Hackaday Writer And Her Breakfast!

OK Jenny, think rationally. They’ve taken the kettle, but I’ve got OpenSCAD and ChatGPT. Those dastardly miscreants won’t come between me and my breakfast, I’m made of sterner stuff! Into the prompt goes the following query:

Continue reading “Now ChatGPT Can Make Breakfast For Me” →

Cheap Kitchen Scale Learns To Speak JSON With ESP32

February 2, 2023 by Jenny List 5 Comments

Smart kitchen appliances are expensive, and more often than not, your usage data goes to whichever company operates the inevitable cloud service. Meanwhile the cheap ones contain substantially the same components without the smarts, so surely a hardware hacker can add a microcontroller to a cheap appliance for a bit of smart home technology without the privacy issues? It’s something [Liore] has done with an Amazon Basics kitchen scale, removing the electronics and wiring up an ESP32 to the load cell instead.

The Wheatstone bridge load cell circuit generates a tiny voltage difference that’s far too small for an ESP32 to measure, so in between the pair is an Avia Semiconductor HX711 strain gauge amplifier module. In addition, there’s a small OLED screen and the two buttons used in the Amazon scale are wired in too, providing the the kitchen scale functionality you’d expect.

Naturally the ESP32 brings along with it WiFi networking capabilities, which [Liore] has taken full advantage of here. By navigating a web browser to its IP address, you’ll receive the scale’s current reading in JSON format. This should make it easy to integrate with other systems, from Home Assistant to OctoPrint. We can see that there is plenty of scope for further enhancements for those prepared to write a little code.

Of course, this isn’t the first enhanced scale we’ve brought you, here’s one with Bluetooth. We’ve also seen hackers dispense with the kitchen-safe trappings and build the load cell directly into their own contraptions.

A Reverse Polish Calculator For Your Keychain

January 31, 2023 by Jenny List 24 Comments

As the smartphone has eaten ever more of the gatgets with which we once surrounded ourselves, it’s with some sadness that we note the calculator becoming a less common sight. It’s with pleasure then that we bring you [Nekopla]’s keychain calculator, not least because it’s a little more than a conventional model. This is a calculator which uses Reverse Polish Notation, or RPN.

A full write-up in Japanese (Google Translate link) carries an impressive level of detail about the project, but in short, it takes an Arduino Pro Micro, an array of keys, and an OLED display, and packages them on a couple of fiberglass prototyping boards in a sandwich between laser-cut Perspex front and rear panels.

The RPN notation is what makes it especially interesting,a system in which where you might be used to writing 2+2= to get 4, in RPN you would write 2 2 + . It allows the use of much simpler code with a stack-based architecture than that used in a conventional calculator. It’s a system that’s usually the preserve of some pretty exclusive machines, so it’s great to see on something with more of the toy about it.

If RPN interests you, then you might like to read our look at the subject, and even feast your eyes on the teardown of a vintage 1975 Sinclair RPN calculator.