Build a $35 400 MHz Logic Analyzer

Build A 400 MHz Logic Analyzer For $35

June 12, 2025 by 15 Comments

What do you do when you’re a starving student and you need a 400 MHz logic analyzer for your digital circuit investigations? As [nanofix] shows in a recent video, you find one that’s available as an open hardware project and build it yourself.

The project, aptly named LogicAnalyzer was developed by [Dr. Gusman] a few years back, and has actually graced these pages in the past. In the video below, [nanofix] concentrates on the mechanics of actually putting the board together with a focus on soldering. The back of the build is the Raspberry Pi Pico 2 and the TXU0104 level shifters.

If you’d like to follow along at home, all the build instructions and design files are  available on GitHub. For your convenience the Gerber files have been shared at PCBWay

Of course we have heaps of material here at Hackaday covering logic analyzers. If you’re interested in budget options check out $13 Scope And Logic Analyzer Hits 18 Msps or how to build one using a ZX Spectrum! If you’re just getting started with logic analyzers (or if you’re not sure why you should) check out Logic Analyzers: Tapping Into Raspberry Pi Secrets.

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Simple Open Source Photobioreactor

June 12, 2025 by 11 Comments

[Bhuvanmakes] says that he has the simplest open source photobioreactor. Is it? Since it is the only photobioreactor we are aware of, we’ll assume that it is. According to the post, other designs are either difficult to recreate since they require PC boards, sensors, and significant coding.

This project uses no microcontroller, so it has no coding. It also has no sensors. The device is essentially an acrylic tube with an air pump and some LEDs.

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COTS Components Combine To DIY Solar Power Station

June 12, 2025 by 19 Comments

They’re marketed as “Solar Generators” or “Solar Power Stations” but what they are is a nice box with a battery, charge controller, and inverter inside. [DoItYourselfDad] on Youtube decided that since all of those parts are available separately, he could put one together himself.

The project is a nice simple job for a weekend afternoon. (He claims 2 hours.) Because it’s all COTS components, it just a matter of wiring everything together, and sticking into a box.  [DoItYourselfDad] walks his viewers through this process very clearly, including installing a shunt to monitor the battery. (This is the kind of video you could send to your brother-in-law in good conscience.)

Strictly speaking, he didn’t need the shunt, since his fancy LiFePo pack from TimeUSB has one built in with Bluetooth connectivity. Having a dedicated screen is nice, though, as is the ability to charge from wall power or solar, via the two different charge controllers [DoItYourselfDad] includes. If it were our power station, we’d be sure to put in a DC-DC converter for USB-PD functionality, but his use case must be different as he has a 120 V inverter as the only output. That’s the nice thing about doing it yourself, though: you can include all the features you want, and none that you don’t.

We’re not totally sure about his claim that the clear cargo box was chosen because he was inspired by late-90s Macintosh computers, but it’s a perfectly usable case, and the build quality is probably as good as the cheapest options on TEMU.

This project is simple, but it does the job. Have you made a more sophisticated battery box, or other more-impressive project? Don’t cast shade on [DoItYourselfDad]: cast light on your work by letting us know about it!. Continue reading “COTS Components Combine To DIY Solar Power Station” →

The Billionth Repository On GitHub Is Really Shitty

June 12, 2025 by 40 Comments

What’s the GitHub repository you have created that you think is of most note? Which one do you think of as your magnum opus, the one that you will be remembered by? Was it the CAD files and schematics of a device for ending world hunger, or perhaps it was software designed to end poverty? Spare a thought for [AasishPokhrel] then, for his latest repository is one that he’ll be remembered by for all the wrong reasons. The poor guy created a repository with a scatalogical name, no doubt to store random things, but had the misfortune to inadvertently create the billionth repository on GitHub.

At the time of writing, the 💩 repository sadly contains no commits. But he seems to have won an unexpectedly valuable piece of Internet real estate judging by the attention it’s received, and if we were him we’d be scrambling to fill it with whatever wisdom we wanted the world to see. A peek at his other repos suggests he’s busy learning JavaScript, and we wish him luck in that endeavor.

We think everyone will at some time or another have let loose some code into the wild perhaps with a comment they later regret, or a silly name that later comes back to haunt them. We know we have. So enjoy a giggle at his expense, but don’t give him a hard time. After all, this much entertainment should be rewarded.

Cat at the door

2025 Pet Hacks Contest: Cat At The Door

June 12, 2025 by 14 Comments

This Pet Hacks Contest entry from [Andrea] opens the door to a great collaboration of sensors to solve a problem. The Cat At The Door project’s name is a bit of a giveaway to its purpose, but this project has something for everyone, from radar to e-ink, LoRa to 3D printing. He wanted a sensor to watch the door his cats frequent and when one of his cats were detected have an alert sent to where he is in the house

There are several ways you can detect a cat, in this project [Andrea] went with mmWave radar, and this is ideal for sensing a cat as it allows the sensor to sit protected inside, it works day or night, and it doesn’t stop working should the cat stand still. In his project log he has a chapter going into what he did to dial in the settings on the LD2410C radar board.

How do you know if you’re detecting your cat, some other cat, a large squirrel, or a small child? It helps if you first give your cats a MAC address, in the form of a BLE tag. Once the radar detects presence of a suspected cat, the ESP32-S3 starts looking over Bluetooth, and if a known tag is found it will identify which cat or cats are outside waiting.

Once the known cat has been identified, it’s time to notify [Andrea] that his cat is waiting for his door opening abilities. To do this he selected an ESP32 board that includes a SX1262 LoRa module for communicating with the portable notification device. This battery powered device has a low power e-paper display showing you which cat, as well as an audio buzzer to help alert you.

To read more details about this project head over to the GitHub page to check out all the details. Including a very impressive 80 page step-by-step guide showing you step by step how to make your own. Also, be sure to check out the other entries into the 2025 Pet Hacks Contest.

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End Of An Era: NOAA’s Polar Sats Wind Down Operations

June 12, 2025 by 16 Comments

Since October 1978, the National Oceanic and Atmospheric Administration (NOAA) has operated its fleet of Polar-orbiting Operational Environmental Satellites (POES) — the data from which has been used for a wide array of environmental monitoring applications, from weather forecasting to the detection of forest fires and volcanic eruptions. But technology marches on, and considering that even the youngest member of the fleet has been in orbit for 16 years, NOAA has decided to retire the remaining operational POES satellites on June 16th.

NOAA Polar-orbiting Operational Environmental Satellite (POES)

Under normal circumstances, the retirement of weather satellites wouldn’t have a great impact on our community. But in this case, the satellites in question utilize the Automatic Picture Transmission (APT), Low-Rate Picture Transmission (LRPT), and High Resolution Picture Transmission (HRPT) protocols, all of which can be received by affordable software defined radios (SDRs) such as the RTL-SDR and easily decoded using free and open source software.

As such, many a radio hobbyist has pointed their DIY antennas at these particular satellites and pulled down stunning pictures of the Earth. It’s the kind of thing that’s impressive enough to get new folks interested in experimenting with radio, and losing it would be a big blow to the hobby.

Luckily, it’s not all bad news. While one of the NOAA satellites slated for retirement is already down for good, at least two remaining birds should be broadcasting publicly accessible imagery for the foreseeable future.

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Learning The Basics Of Astrophotography Editing

June 12, 2025 by 13 Comments

Astrophotography isn’t easy. Even with good equipment, simply snapping a picture of the night sky won’t produce anything particularly impressive. You’ll likely just get a black void with a few pinpricks of light for your troubles. It takes some editing magic to create stunning images of the cosmos, and luckily [Karl Perera] has a guide to help get you started.

The guide demonstrates a number of editing techniques specifically geared to bring the extremely dim lights of the stars into view, using Photoshop and additionally a free software tool called Siril specifically designed for astrophotograpy needs. The first step on an image is to “stretch” it, essentially expanding the histogram by increasing the image’s contrast. A second technique called curve adjustment performs a similar procedure for smaller parts of the image. A number of other processes are performed as well, which reduce noise, sharpen details, and make sure the image is polished.

While the guide does show some features of non-free software like Photoshop, it’s not too hard to extrapolate these tasks into free software like Gimp. It’s an excellent primer for bringing out the best of your astrophotography skills once the pictures have been captured, though. And although astrophotography itself might have a reputation as being incredibly expensive just to capture those pictures in the first place, it can be much more accessible by using this Pi-based setup as a starting point.

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