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31 Articles

FM Radio From Scratch Using An Arduino

December 4, 2020 by 50 Comments

Building radio receivers from scratch is still a popular project since it can be done largely with off-the-shelf discrete components and a wire long enough for the bands that the radio will receive. That’s good enough for AM radio, anyway, but you’ll need to try this DIY FM receiver if you want to listen to something more culturally relevant.

Receiving frequency-modulated radio waves is typically more difficult than their amplitude-modulated cousins because the circuitry necessary to demodulate an FM signal needs a frequency-to-voltage conversion that isn’t necessary with AM. For this build, [hesam.moshiri] uses a TEA5767 FM chip because of its ability to communicate over I2C. He also integrated a 3W amplifier into this build, and everything is controlled by an Arduino including a small LCD screen which displays the current tuned frequency. With the addition of a small 5V power supply, it’s a tidy and compact build as well.

While the FM receiver in this project wasn’t built from scratch like some AM receivers we’ve seen, it’s still an interesting build because of the small size, I2C capability, and also because all of the circuit schematics are available for all of the components in the build. For those reasons, it could be a great gateway project into more complex FM builds.

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STM32 Gets Up Close And Personal With Mandelbrot

October 25, 2020 by 12 Comments

The Mandelbrot set is a curious mathematical oddity that, while interesting in its own right, is also a useful tool for benchmarking various types of computers. Its constant computing requirement when zooming in and out on the function, combined with the fact that it can be zoomed indefinitely, means that it takes some quality hardware and software to display it properly. [Thanassis] has made this a pet project of his, running Mandelbrot set visualizations in different ways on many different hardware platforms.

This particular one is based on an STM32 board called the Blue Pill, which [Thanassis] chose because he hadn’t yet done a continuous Mandelbrot zoom on a microcontroller yet. The display is handled by a tiny 16K IPS color screen, and some clever memory tricks had to come into play in order to get smooth video output since the STM has only 20 kB available. The integer multiplication is also tricky on a platform this small while keeping the continuous zoom function, so it’s limited to fixed point multiplication.

Even with the limitations of the platform, he is still able to achieve nearly double-digit FPS rates with this one. If you want to play around with graphics like this on an STM platform, [Thanassis] has released all of the source code on his GitHub page, but if you’d like to see more Mandelbrot manipulation you can check out one of his older projects where he built a similar project on an FPGA.

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LIDAR Built On Familiar Platform

April 11, 2020 by 7 Comments

Moore’s law may have reached its physical limit for transistor density, but plenty of other technologies are still on that familiar path of getting smaller and smaller as time passes. It looks like LIDAR is no exception to this trend either. This project from [Owen] shows a fully-functional LIDAR system for about $20 and built almost entirely on top of an ESP32.

The build uses a Time-Of-Flight IR laser range sensor controlled by the ESP32, and the sensor is much smaller than even the ESP32’s footprint so it takes up very little extra space. To get it to function as a LIDAR system instead of just a simple rangefinder it does need a motor in order to rotate itself to see its entire space. Besides its small form factor and low cost, it also has a handy user interface that can run anywhere an HTML5 browser can run, making the use of the system easy and straightforward as well. All of the code is available on the project’s GitHub page.

We wouldn’t expect a system like this to be driving an autonomous car anytime soon, it’s update rate is far too slow, but its intent for small robots and even as an educational demo for learning LIDAR is second to none. If you do need a little more power in a LIDAR system but still don’t want to break the bank, we featured this impressive setup a few weeks ago.

Tiny ESP32 Fits Inside USB-A Connector

September 28, 2019 by 24 Comments

The ESP32 was introduced a few years ago as an inexpensive way to outfit various microcontrollers with WiFi or Bluetooth. Since then it has been experimented with and developed on, thanks to its similarities to the ESP8266 and the ability to easily program it. Watching the development of this small chip has truly been fascinating as it continues to grow. Or, in this case, shrink.

The latest development in the ESP32 world comes from [femtoduino] who, as the name suggests, makes very small things. This one is a complete ESP32 which fits inside a USB-A connector. The brains of the projects is the ESP32-D2WD which is a dual core chip with 2 Mb of memory, making it more than capable. In fact, a big part of this project was [femtoduino]’s modifications to MicroPython in order to allow it to run on this chipset. For that alone, it’s cool.

This project is impressive for both reasons, both the size and the addition to the MicroPython libraries. If you need something really really tiny, for whatever reason, you might want to look into picking up one of these. Be careful though, and be sure to get the latest version of the SDK.

After The Con: Da Bomb Badge Post Mortem

September 2, 2019 by No comments

We’ve reported on the world of electronic badges here at Hackaday since their earliest origins in [Joe Grand]’s work for DEF CON 14 in 2006. In that time we’ve seen an astonishing variety of creations, covering everything from abstract artwork to pure functionality in a wearable device. But it’s not been quite so often that we’ve looked at the other side of the BadgeLife coin, so it’s fascinating to read [John Adams]’ account of the work that went into the production of this year’s 500-piece run of the Da Bomb DEF CON indie badge.

In it, [John] goes over scheduling worries, component sourcing issues, PCB assembly delays, and an in-depth look into the finances of such a project. In case anyone is tempted to look at Badgelife as the route to millions, it rapidly becomes apparent that simply not losing too much money is sometimes the best that can be hoped for. There were a few design problems, one of them being that the SAO I2C bus was shared with the LED controller, resulting in some SAOs compatibility issues. In particular the AND!XOR DOOM SAO had its EEPROM erased, creating something of a headache for the team.

A surprise comes in the distribution: obviously shipping is expensive, so you’d think badge pick-ups at the con would be straightforward alternative. Unfortunately, they became something of a millstone in practice, and organising them was a Herculean task. Astoundingly, some paying customers didn’t bother turn up for their badges. Which was especially infuriating since the team lost valuable conference time waiting for them.

Some of you are BadgeLife creators and will nod sagely at this. Still more of you will wish you were BadgeLife creators and find it a useful primer. For everyone else it’s a fascinating read, and maybe makes us appreciate our badges a bit more.

The images may have departed, but just to return to the origins of BadgeLife, here’s our coverage of that first [Joe Grand] badge.

Pop-Up Outlet Helps Make The Most Of A Tiny Shop

August 9, 2019 by 8 Comments

You’ve got to admire the steps some people take to squeeze a shop into a small space. Finding ways to pack in ever more tools and to work on bigger and bigger projects become ends to themselves for some, and the neat little tricks they find to do so can be really instructive.

Take this workbench pop-up outlet strip for example. The shop that [Woodshop Junkies] occupies appears to be a single-car garage, on the smallish size in the first place, that is almost entirely filled with a multipurpose workbench. It provides tons of storage underneath and a massive work surface on top, but working with small power tools means stretching extension cords across the already limited floor space and creating a tripping hazard. So he claimed a little space on the benchtop for a clever trap door concealing a small tray holding an outlet strip.

The tray rides on short drawer glides and, thanks to a small pneumatic spring, pops up when the door is unlatched. There was a little trouble with some slop in the glides causing the tray to jam, but that was taken care of with a simple roller bearing. The video below shows its construction and how it stays entirely out of the way until needed.

As cool as this build is, it’s just icing on the small shop cake when compared to the workbench. [Woodshop Junkies] has a complete playlist covering the build which is worth watching. And you might want to refer to our tiny shop roundup for more tips on getting a lot done in a little space.

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Many Uses For A Single Button

December 5, 2018 by 18 Comments

When building projects with a simple goal in mind, it’s not unheard of for us to add more and more switches, buttons, and complexity as the project goes through its initial prototyping stages. Feature creep like this tends to result in a tangled mess rather than a usable project. With enough focus, though, it’s possible to recognize when it’s happening and keep to the original plans. On the other hand, this single-button project with more than one use seems to be the opposite of feature creep. (YouTube, embedded below.)

[Danko]’s project has one goal: be as useful as possible while only using a single button and a tiny screen. Right now the small handheld device can be used as a stopwatch, a counter, and can even play a rudimentary version of flappy bird. It uses an Arduino Pro Mini, a 64×48 OLED screen running on I2C, and has a miniscule 100 mAh 3.7V battery to power everything. The video is worth watching if you’ve never worked with this small of a screen before, too.

Getting three functions out of a device with only one button is a pretty impressive feat, and if you can think of any other ways of getting more usefulness out of something like this be sure to leave it in the comments below. [Danko] is no stranger to simple projects with tiny screens, either. We recently featured his homebrew Arduino calculator that uses an even smaller screen.

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