Author: Bryan Cockfield

1750 Articles

Mushrooms As Computer Memory

October 28, 2025 by 35 Comments

Fungi make up a massive, interconnected part of Earth’s ecosystems, yet they’re vastly underrepresented in research and public consciousness compared to plants and animals. That may change in the future though, as a group of researchers at The Ohio State University have found a way to use fungi as organic memristors — hinting at a possible future where fungal networks help power our computing devices.

A memristor is a passive electronic component whose resistance changes based on the voltage and current that has passed through it, which means it can effectively remember past electrical states even when power is removed. To create these circuit components with fungus, the researchers grew shiitake and button mushroom mycelium for these tests, dehydrated their samples for a number of days, and then attached electrodes to the samples. After misting them briefly to restore conductivity, the samples were exposed to various electrical wave forms at a range of voltages to determine how effective they were at performing the duties of a memristor. At one volt these systems were the most consistent, and they were even programmed to act like RAM where they achieved a frequency of almost 6 kHz and an accuracy of 90%.

In their paper, the research group notes a number of advantages to building fungal-based components like these, namely that they are much more environmentally friendly and don’t require the rare earth metals that typical circuit components do. They’re also easier to grow than other types of neural organoids, require less power, weigh less, and shiitake specifically is notable for its radiation resistance as well. Some work needs to be done to decrease the size required, and with time perhaps we’ll see more fungi-based electrical components like these.

HRV Gets Home Automation Upgrades

October 26, 2025 by 5 Comments

In our modern semi-dystopia, it seems like most companies add automation features to their products to lock them down and get consumers to buy even more proprietary, locked-down components. The few things that are still user-upgradable are getting fewer and farther between, but there are still a few things that can be modified and improved to our own liking like this control panel for a heat recovery ventilator (HRV).

HRVs are systems that exchange fresh, outside air with stale, inside air while passing them both through a heat exchanger to keep from wasting energy. Many systems run continuously but they aren’t always needed, so some automation is beneficial. This upgrade from [vincentmakes] improves the default display for a Zehnder Comfoair Q350 HRV with a color display as well as adding it in to a home automation system, letting a user control fan speeds remotely as well as alerting the user when it’s time for filter replacements and providing up-to-date information from all the sensors in the HRV.

The project builds on a previous project which adapted an ESP32 to interact with the CAN bus used on these devices. With these upgrades the user can forgo the $300 proprietary upgrade that would be needed to get the same functionality otherwise. It’s also fully open-source so all that’s needed is to flash the firmware, replace the display, and enjoy the fresh air. There’s other modern HVAC equipment that can benefit from new controllers and a bit of automation as well.

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Tiny UPS Keeps WiFi Online

October 24, 2025 by 29 Comments

For any mission-critical computer system, it’s a good idea to think about how the system will handle power outages. At the very least it’s a good idea to give the computer enough time to gracefully shut down if the power outage will last for an indefinite time. But for extremely critical infrastructure, like our home Wi-Fi, we might consider a more long-term battery backup that can let us get through the longest of power outages.

Part of why this project from [Next Builder] works so well is that most off-the-shelf routers don’t actually use that much energy. Keeping that and a modem online when the power is out only requires a few lithium batteries. To that end, three lithium ion cells are arranged in series to provide the router with between 9 and 12 volts, complete with a battery management system (BMS) to ensure they aren’t over- or under-charged and that they are balanced. The router plugs directly into a barrel jack, eliminating any switching losses from having to use an inverter during battery operation.

While [Next Builder] is a student who lives in an area with frequent interruptions to the electricity supply, this does a good job of keeping him online. If you’re planning for worse or longer outages, a design like this is easily adapted for more batteries provided the correct BMS is used to keep the cells safely charged and regulated. You can also adapt much larger UPS systems to power more of your home’s electrical system, provided you can find enough batteries.

Automatically Serving Up Canned Cat Food

October 23, 2025 by 18 Comments

If there’s any one benefit to having a cat as a pet instead of a dog, it’s that they’re a bit more independent and able to care for themselves for many days without human intervention. The only thing that’s really needed is a way to make sure they get food and water at regular intervals, but there are plenty of off-the-shelf options for these tasks. Assuming your cat can be fed dry food, that is. [Ben Heck]’s cat has a health problem that requires a special canned wet food, and since there aren’t automatic feeders for this he built his own cat-feeding robot.

Unlike dry food that can dispense a measured amount from a hopper full of food, the wet food needs to be opened and dispensed every day. To accomplish this, his robot has a mechanism that slowly slides a wedge under the pull tab on the can, punctures the can with it, and then pulls it back to remove the lid. From there the food is ejected from the feeder down a ramp to a waiting (and sometimes startled) cat. The cans are loaded into 3D-printed cartridges and then stacked into the machine on top of each other, so the machine can dispense food cans until it runs out. This design has space for six cans.

Although there are many benefits to having pets of any sort, one of the fun side quests of pet ownership is building fun things for them to enjoy or to make caring for them easier. We even had an entire Hackaday contest based on this premise. And, if biological life forms aren’t your cup of tea, there are always virtual pets to care for as well.

Thanks to [Michael C] for the tip!

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Keep An Eye On Your Air-Cooled Engine

October 23, 2025 by 23 Comments

There was a time, long ago, when passenger vehicles used to be much simpler than they are today. There were many downsides of this era, safety chief among them, but there were some perks as well. They were in general cheaper to own and maintain, and plenty could be worked on with simple tools. There’s perhaps no easier car to work on than an air-cooled Volkswagen, either, but for all its simplicity there are a number of modern features owners add to help them with these antiques. [Pegor] has created his own custom engine head temperature monitor for these vehicles.

As one could imagine with an air-cooled engine, keeping an eye on the engine temperature is critical to ensuring their longevity but the original designs omitted this feature. There are some off-the-shelf aftermarket solutions but this custom version has a few extra features that others don’t. It’s based on a ATMega32u4 microcontroller and will work with any K-type thermocouple, and thanks to its open nature can use a wide array of displays. [Pegor] chose one to blend in with the rest of the instrumentation on this classic VW. The largest issue that needed to be sorted out was around grounding, but a DC-DC converter created an isolated power supply for the microcontroller, allowing the thermocouple to be bonded to the grounded engine without disrupting operation of the microcontroller.

The finished product looks excellent and does indeed blend in to the dashboard more than the off-the-shelf temperature monitor that was in use before. The only thing that is planned for future versions is a way to automatically dim the display when the headlights are on, as [Pegor] finds it a little bright at night. We also enjoy seeing anything that helps these antiques stay on the road more reliably as their modern descendants don’t have any of the charm or engineering of these classics.

Channel Surfing Nostalgia Machine

October 17, 2025 by 6 Comments

As any generation of people get older, they tend to look back fondly on their formative years when there was less responsibility and more wonder. Even if things have objectively improved, we often have a fondness for the past. Such is the case for cable television, where even though ads were everywhere and nothing was on-demand, we can see that something was lost from this era in the modern streaming ecosystem. [Ricardo] brought back the good parts of this golden era of cable TV with this small channel surfing television.

The project attempts to keep the good parts of this era while discarding things we certainly don’t miss. The ability to channel surf is still here, with a rotary encoder standing in for an antique television channel selector knob, but dealing with any telecommunications company is out, including those of the Internet variety. Instead it is a fully offline machine with the user able to curate their own channels and programming with a Flask application, and [Ricardo]’s includes his own collection of commercials from Argentina.

The hardware itself is fairly straightforward as well, with a Raspberry Pi doing the heavy lifting, paired with a small screen and enclosed in a retro-themed television case. It’s a clever throwback to a time where we might not know what we wanted to see but there was always something on. Builds like this are gaining popularity right now as well, and we’ve even seen them recreate the cable company’s preview channel as well.

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A New Golden Age Of Browser Games

October 17, 2025 by 20 Comments

Arguably, the golden age of browser gaming occurred in the 00s mostly revolving around Adobe Flash. This was an era with high creativity and a low barrier of entry, and also decentralized from gatekeeping app stores. Sadly, these times have passed us by as the security concerns around Flash led to its discontinuation and most casual gamers have migrated to the app store for their fix. But that doesn’t stop some from continuing to bring gaming to the browser, even if those games were never intended for it in the first place like this browser port of Celeste.

Celeste is an indie platformer where the player climbs a mysterious mountain while confronting her inner struggles. Originally meant for consoles and PC, a group of friends including [velzie], [bomberfish], and [Toshit] aka [r58Playz] took this as a challenge especially after seeing someone else’s half finished web port of this game. Most of the build revolves around WebAssembly (wasm) and around “cursed” .NET runtime hacks which also allow the port to run the community-made Everest mod loader. It uses a multithreaded and JIT compiling version of mono-wasm backported from .NET 10 to .NET 9 to maximize performance. The team actually first started by porting Terraria to the browser, and then moved on to this Celeste port from there.

The port of Celeste can be played here, and their port of Terraria is also available, although may not support a ton of Hackaday traffic so some patience is advised. There are also GitHub repositories for Celeste and Terraria as well.  With impressive ports of relatively modern games moving into the browser, perhaps we’re entering a new golden age of browser gaming; we’ve also seen things like Minecraft implemented in only HTML and CSS lately as well.