Dreamcast Homebrew Gets Boost From SD Card Cache

While it might have been a commercial failure compared to contemporary consoles, the Sega Dreamcast still enjoys an active homebrew scene more than twenty years after its release. Partly it’s due to the fact that you can burn playable Dreamcast discs on standard CD-Rs, but fans of the system will also point out that the machine was clearly ahead of its time in many respects, affording it a bit of extra goodwill in the community.

That same community happens to be buzzing right now with news that well-known Dreamcast hacker [Ian Micheal] has figured out how to cache data to an SD card via the console’s serial port. At roughly 600 KB/s the interface is too slow to use it as swap space for expanding the system’s paltry 16 MB of memory, but it’s more than fast enough to load game assets which otherwise would have had to be loaded into RAM.

A third-party Dreamcast SD adapter.

In the video below, [Ian] shows off his new technique with a port of DOOM running at 640×480. He’s already seeing an improvement to framerates, and thinks further optimizations should allow for a solid 30 FPS, but that’s not really the most exciting part. With the ability to load an essentially unlimited amount of data from the SD card while the game is running, this opens the possibility of running mods which wouldn’t have been possible otherwise. It should also allow for niceties like saving screenshots or game progress to the SD card for easy retrieval.

[Ian] says he’ll be bringing the same technique to his Dreamcast ports of Quake and Hexen in the near future, and plans on posting some code to GitHub that demonstrates reading and writing to FAT32 cards so other developers can get in on the fun. The downside is that you obviously need to have an SD card adapter plugged into your console to make use of this technique, which not everyone will have. Luckily they’re fairly cheap right now, but we wouldn’t be surprised if the prices start climbing. If you don’t have one already, now’s probably the time to get one.

To be clear, this technique is completely separate from replacing the Dreamcast’s optical drive with an SD card, which itself is a very popular modification that’s helped keep Sega’s last home console kicking far longer than anyone could have imagined.

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Old Textbooks Galore

This collection of public domain books proclaims to not be about survival, but for survivors. It is a extensive collection of text books, manuals, etc., in over 150 categories from Accounting to Woodworking. Because of the copyright duration laws, most are around one hundred years old.

You might not want to have your appendix removed by someone who has only learned surgery from reading Dr John Sluss’s 1908 tome, “Emergency Surgery for the General Practitioner, with 584 illustrations, some of which are printed in colors“. But some knowledge is timeless. And much is of historical interest as well, helping us get a better appreciation of what bodies of knowledge people had in the beginning of the last century. There are books on farming, forging and casting, steam engines, clockmaking, telegraph and telephone, and even back issues of Scientific American and 73 magazines, just to name a few.

Here’s a random sampling of a few illustrations from electronics-related books.

High speed electrons from “Inside the Vacuum Tube” by John F. Rider, 1945, a relatively modern book from this collection. This book alone is worth downloading just to see the excellent illustrations. Mr Rider wrote so many technical books that he formed his own publishing company.

Using triangles from “Mechanical Drawing, Prepared for the Students of the Massachusetts Institute of Technology” by Linus Faunce, 1898.

The Weidemann system of wiring lamps, from “Electric-Wiring, Diagrams and Switchboards” by Newton Harrison E.E., published in 1906, complete with “one hundred and five illustrations showing the principles and technics of the art of wiring”. This system employed equal lengths of wires between each lamp in a (failed) attempt to make the voltage drop the same for each bulb.

Do you have any timeless reference or text books you like to use? Let us know down below in the comments. And thanks to [David Gustafik] for the tip.

Hacking A Solar Inverter RF Interface

One of the main advantages of cheap wireless modules is that they get used in consumer electronics, so if you know what’s being used you can build your own compatible hardware. While investigating the RF interface used in a series of cheap “smart” solar inverters [Aaron Christophel], created an Arduino library to receive inverter telemetry using a $2 RF module. See the demonstration after the break.

[Aaron] bought the inverter and ~40 euro USB “Data Box” that allows the user to wirelessly monitor the status of the inverter. Upon opening the two units, he found that they used LC12S 2.4Ghz modules, which create a wireless UART link. With a bit of reverse engineering, he was able to figure out the settings for the RF modules and the serial commands required to request the status of the inverter. He doesn’t delve into the possible security implications, but there doesn’t appear to be any form of encryption in the link. It should be possible for anyone with a module to sniff the messages, extract the ID of the inverter, and hijack the link. Just knowing the status of the inverter shouldn’t be all that dangerous, but he doesn’t mention what other commands can be sent to the module. Any others could have more severe implications.

Sniffing the wireless signal flashing through the air around us is a regular topic here on Hackaday. From testing the security of WiFi networks with an ESP32 to monitoring SpaceX launches with an SDR, the possibilities are infinite.

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Riding Mower Repair Uncovers Miniature Culprit

Most people would be pretty upset it the lawn mower they spent $4,000 USD on had a major failure within the first year of owning it. But for [xxbiohazrdxx], it was an excuse to take a peek under the hood and figure out what brought down this state-of-the-art piece of landscaping gear.

It should be said that, at least technically, the Husqvarna TS 348XD in question was still working. It’s just that [xxbiohazrdxx] noticed the locking differential, which is key to maintaining traction on hilly terrain, didn’t seem to be doing anything when the switch was pressed. Since manually moving the engagement lever on the transmission locked up the differential as expected, the culprit was likely in the electronics.

Testing the dead actuator.

As [xxbiohazrdxx] explains, the switch on the dash is connected to a linear actuator that moves the lever on the transmission. The wiring and switch tested fine with a multimeter, but when the actuator was hooked up to a bench power supply, it didn’t move. Even more telling, it wasn’t drawing any power. Definitely not a good sign. Installing a new actuator would have solved the problem, but it was an expensive part that would take time to arrive.

Repairing the dead actuator seemed worth a shot at least, so [xxbiohazrdxx] cracked it open. The PCB looked good, and there were no obviously toasted components. But when one of the internal microswitches used to limit the travel of the actuator was found to be jammed in, everything started to make sense. With the switch locked in the closed position, the actuator believed it was already fully extended and wouldn’t move. After opening the switch itself and bending the contacts back into their appropriate position, everything worked as expected.

A tiny piece of bent metal kept this $4,000 machine from operating correctly.

As interesting as this step-by-step repair process was, what struck us the most is [xxbiohazrdxx]’s determination to fix rather than replace. At several points it would have been much easier to just swap out a broken part for a new one, but instead, the suspect part was carefully examined and coaxed back to life with the tools and materials on-hand.

While there’s plenty of folks who wouldn’t mind taking a few days off from lawn work while they wait for their replacement parts to arrive, not everyone can afford the luxury. Expedient repairs are critical when your livelihood depends on your equipment, which is why manufacturers making it harder and more expensive for farmers to fix their tractors has become such a major issue in right to repair battles all over the globe.

Home Automation Controller Uses Chalk

Responding to the Rethink Displays challenge of the 2021 Hackaday Prize contest, freelance design engineer [Rick Pannen] brings a retro look to his DIY home automation controller. You could be forgiven for not even realizing it is a controller at first glance. [Rick] built this using a magnetic chalk board and installed all the control electronics on the back. The main processor is a Raspberry Pi 400 running Raspian with IOBroker and Node-Red. Panel lettering and graphics are done free-hand with, you guessed it, chalk.

The controls on this panel are an eclectic hodgepodge of meters, switches, and sensors that [Rick] scored on eBay or scavenged from friends. We are curious about the simple-looking rotary dial that sends a pulse train based on the number set on the dial — this seems to have all the functionality of an old phone’s rotary dial without any of the fun.

But [Rick]’s design allows for easy changes — dare we say, it encourages them — so maybe we’ll see a salvaged rotary dial added in future revisions. Also note the indoor lighting ON/OFF switch that must be a real joy to operate. We wonder, is there any way the controls could be magnetized and moved freely around the board without permanently attaching them? Maybe an idea for version 4 or 5.

This design has a lot of possibilities, and we look forward to any upgrades or derivative versions of this unique home automation controller. Let us know in the comments below if you have any suggestions for expanding upon this idea.

ShakeAlert Promises Earthquake Early Warning Of About 10 Seconds

Earthquakes are highly destructive when they strike, and unlike many other natural disasters, they often hit with minimal warning. Unlike hurricanes and floods, and even volcanoes to an extent, earthquakes can be very difficult to predict. However, in recent decades, warning networks have proliferated around the world, aiming to protect affected communities from the worst outcomes in the event of a large tremor.

ShakeAlert is the name of the earthquake monitoring project run by the United States Geological Survey, which has just announced that it now offers early warning services to the entire west coast of the United States. Let’s take a look at how earthquake monitoring works, how that feeds into early warnings, and how this can make a difference in the case of a major quake.

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Hackaday Podcast 121: Crazy Bikes, DIY Flip Dots, EV Mountain Climbing, And Trippy Tripterons

Hackaday editors Mike Szczys and Elliot Williams discuss a great week of hardware hacks. Two delightful mechanical hacks focus on bicycles: one that puts a differential on the front fork, and the other a flywheel between the knees. Elliot was finally impressed by something involving AI — a machine-learning guitar pedal. You’ve heard of a delta bot? The tripteron is similar but with a single rail for the three arms. After a look at flip dots, tiny robots, and solar air planes we close the show geeking out about racing electric vehicles up a hill and stories of the hardware that has made closed captions possible.

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Direct download (55 MB or so.)

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