DIy Arduino FM radio enclosure with the lid off, showing the electronics inside

DIY Arduino Due TEA5767 FM Radio

October 8, 2022 by Dave Walker 10 Comments

Older hackers will remember that a crystal set radio receiver was often one of the first projects attempted. Times have changed, but there’s still something magical about gathering invisible signals from the air and listening to the radio on a homemade receiver. [mircemk] has brought the idea right up to date by building an FM radio with an OLED display, controlled with a rotary encoder.

The design is fairly straightforward, based as it is on another project that [mircemk] found on another site, but the build looks very slick and would take pride of place on any hacker’s workbench. An Arduino Due forms the heart of the project, controlling a TEA5767 module, an SH1106 128×64 pixel OLED display and a rotary encoder. The sound signal is passed through an LM4811 headphone amplifier for private listening, and a PAM8403 Class D audio amplifier for the built-in loudspeaker. The enclosure is made from PVC panels, and accented with colored adhesive tape for style.

It’s easier than ever before to quickly put together projects like this by connecting pre-built modules and downloading code from the Internet, but that doesn’t mean it’s not a worthwhile way to improve your skills and make some useful devices like this one. There are so many resources available to us these days and standing on the shoulders of giants has always been a great way to see farther.

We’ve shown some other radio projects using Arduinos and the TEA5767 IC in the past, such as this one on a tidy custom PCB, and this one built into an old radio case.

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Hackaday Podcast 187: The Sound Of Gleeful Gerbils, The Song Of The Hard Drive, And A Lipstick Pickup Lullaby

September 30, 2022 by Kristina Panos 2 Comments

This week, Editor-in-Chief Elliot Williams and Assignments Editor Kristina Panos gushed about NASA’s live obliteration of minor planet Dimorphos using a probe outfitted with a camera. Spoiler alert: the probe reaches its rock-dappled rocky target just fine, and the final transmitted image has a decidedly human tinge.

Kristina brought the mystery sound again this week, much to Elliot’s sonic delight. Did he get it? Did he figure it out? Well, no. The important thing is one of you is bound to get it.

We kick off the hacks with a really neat 3D printed linkage that acts as an elevator for a marble run, and then we discuss a mid-century hack that helps you decide whether it’s time to emerge from the fallout shelter using the contents of your typical 1950s pockets. We spent a few minutes comparing our recent radiation exposure levels — Kristina wins with about a dozen x-rays so far this year, but no full-body CT scans. Then we talk guitars for a bit, remember a forgotten CPU from TI, and spend a few cycles talking about a tone-wheel organ that sounds like a chorus of gleeful gerbils.

Finally, we talk toner transfer for 3D prints, argue in defense of small teams versus large committees, and get all tangled up in cursive.

Direct download.

Check out the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

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The 1337 PNG Hashquine

September 28, 2022 by Jonathan Bennett 7 Comments

A hashquine is a fun way to show off your crypto-tricks — It’s a file that contains its own hash. In some file types it’s trivial, you just pick the hash to hit, and then put random data in a comment or other invisible field till you get a collision. A Python script that prints its own hash would be easy. But not every file type is so easy. Take PNG for instance. these files are split into chunks of data, and each chunk is both CRC-32 and adler32 checksummed. Make one change, and everything changes, in three places at once. Good luck finding that collision. So how exactly did [David Buchanan] generate that beautiful PNG, which does in fact md5sum to the value in the image? Very cleverly.

Thankfully [David] shared some of his tricks, and they’re pretty neat. The technique he details is a meet-in-the-middle hack, where 36 pairs of MD5 collision blocks are found, with the understanding that these 36 blocks will get added to the file. For each block, either A or B of the pair will get plugged in at that location, and the md5sum won’t change. It’s a total of 2^36 possible combinations of these blocks, which is more computation than was practical for this particular hack. The solution is to pre-compute the results of every possible combination of the first 18 blocks, and store the results in a lookup table. The second half of the collisions are run backwards from a target CRC value, and the result checked against the lookup table. Find a hit, and you just found a series of blocks that matches both your target md5sum and CRC32 results.

Thanks to [Julian] for the tip! And as he described it, this hack is one that gets more impressive the more you think about it. Enjoy!

The MOS 7600 Video Game Chip Gives Up Its Secrets

September 7, 2022 by Jenny List 5 Comments

A good chip decapping and reverse engineering is always going to capture our interest, and when it comes from [Ken Shirriff] we know it’s going to be a particularly good one. This time he’s directed his attention to the MOS 7600 all-in-one video game chip (Nitter), a mostly forgotten device from the 6502 chipmaker which we featured a few weeks ago when it was the subject of a blogger’s curiosity. The question then was whether it contained a microprocessor or not and even whether it was another 6502 variant, and the answer revealed in the decapping answers that but will disappoint the 6502 camp.

On the chip is a mixture of analog and digital circuitry, with some elements of a more traditional game chip alongside a ROM, a PLA, and a serial CPU core. The PLA stores pixel data while the ROM stores the CPU code, and the CPU serves to perform calculations necessary to the games themselves. He hasn’t fully reverse-engineered either, but the two areas of the chip are mask-programmed to produce the different games with which the chip could be found.

So the answer to the original question is that there is a CPU on board, but it’s not a 6502 and the operation is a hybrid between dedicated game chip and CPU-controlled chip. What we find interesting is that this serial CPU core might have as we mused in the previous piece made the heart of a usable 1970s microcontroller, was this a missed opportunity on the part of MOS? We’ll never know, but at least another piece of early video game history has been uncovered.

The 7805 Is Dead! Long Live The 7805!

September 5, 2022 by Al Williams 70 Comments

The 78XX series of regulators are very handy to use. If you need, say, a 5V regulator, you grab a 7805, add a capacitor for stability, and send in enough voltage for the regulator to work with. Cheap and easy. However, the part is not without its faults.

A stock 7805 can’t convert 5.1V to 5V. You need to have a good bit more voltage coming in. But the more voltage you put in, the more the part is going to dump out as heat. So running from 9V is going to be cooler than running from 24V. All that heat isn’t very energy efficient on batteries, either. [Stefan] wanted to do better, so he made a drop-in replacement for these venerable regulators some time ago. But he’s recently made the board layouts available so you can build your own replacement, too.

The device accepts 4.5 to 16V, and you can select the output voltage using two resistors. You can draw up to 2A out of the regulator, which is more than you can say for a stock 7805.

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Custom Calculator Brings Us Back To The 70s

September 1, 2022 by Bryan Cockfield 7 Comments

There are certain design aesthetics from every era that manage to survive the fads of their time and live throughout history. Ancient Greek architecture is still drawn upon for design inspiration in modern buildings, the mid-century modern style from the 60s still inspires various designs of consumer goods, and the rounded, clean looking cars from the 90s are still highly desirable qualities in automotive design. For electronics, though, we like this 70s-inspired calculator that [Aaron] recently built.

The calculator hearkens back to the days of calculators like the HP-29C with its large buttons and dot-matrix display. [Aaron] built the case out of various woods with a screen angled towards the user, and it uses a LCD display similar to those found in antique calculators. The brain of the calculator is an Arduino which fits easily into the case, and [Aaron] also built the keyboard from scratch with Cherry MX-style mechanical keys soldered together into a custom shape.

The software to run the calculator is fairly straightforward, but we are most impressed with the woodworking, styling, and keyboard design in this build. [Aaron] is also still ironing out some bugs with the power supply as it uses a DC-DC converter to power the device from a single lithium battery. For those who are more fond of early 2000s graphing calculators instead, be sure to take a look at this graphing calculator arcade cabinet.

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YouTube Like It’s 1970s France With This Minitel-VCR Mashup

August 27, 2022 by Dan Maloney 10 Comments

When it’s not just sticking fake gears on things and calling it a day, the Steampunk look is pretty cool. Imagining technology in a world stuck with Victorian aesthetics is a neat idea, and one that translates to the look of other time periods — Fallout, anyone?

But what if you try to create a technological aesthetic based on a more recent and less celebrated time? That’s what [ghettobastler] has attempted with this somewhat bizarre Minitel-YouTube-VCR mash-up. Taking inspiration from a webcomic’s take on “Formicapunk,” modern tech based on the aesthetic of the wildly successful French videotex service of the 70s and 80s, the system uses a very cool Minitel 1B terminal and a Raspberry Pi 3.

With the help of a level-shifting circuit, the Mintel and the Pi talk over serial, allowing the terminal to be used as, well, a terminal for the Pi. Videos are downloaded from YouTube by the Pi, which sends the video to the VCR from its composite output, and controls the VCR with an IR LED that emulates the original remote. Come to think of it, just watch the video below — it’s probably easier than trying to describe it.

It’s weird, true, but we love the look of that Minitel terminal. Something about it just screams cyberdeck; if anyone has a spare one of these, get busy and put something together for our Cyberdeck Design Contest.

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