Upgrading RAM On A Honda Infotainment System

February 10, 2025 by 5 Comments

Car infotainment systems somehow have become a staple in today’s automobiles, yet when it comes down to it they have all the elegance of a locked-down Android tablet. In the case of the Honda infotainment system that [dosdude1] got from a friend’s 2016/2017-era Honda Accord, it pretty much is just that. Powered by a dual-core Cortex-A15 SoC, it features a blazin’ 1 GB of RAM, 2 GB of storage and runs Android 4.2.2. It’s also well-known for crashing a lot, which is speculated to be caused by Out-of-RAM events, which is what the RAM upgrade is supposed to test.

After tearing down the unit and extracting the main board with the (Renesas) SoC and RAM, the SoC was identified as being an automotive part dating back to 2012. The 1 GB of RAM was split across two Micron-branded packages, leaving one of the memory channels on the SoC unused and not broken out. This left removing the original RAM chips to check what options the existing pads provided, specifically potential support for twin-die chips, but also address line 15 (A15). Unfortunately only the A15 line turned out to be connected.

This left double capacity (1 GB) chips as the sole option, meaning a total of 2 GB of RAM. After installation the infotainment system booted up, but only showed 1 GB installed. Cue hunting down the right RAM config bootstrap resistor, updating the boot flags and updating the firmware to work around the LINEOWarp hibernation image that retained the 1 GB configuration. Ultimately the upgrade seems to work, but until the unit is reinstalled in the car and tested it’s hard to say whether it fixes the stability issues.

Thanks to [Dylan] for the tip.

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Make Custom Shirts With A 3D Print, Just Add Bleach

February 10, 2025 by 38 Comments

Bleach is a handy way to mark fabrics, and it turns out that combining bleach with a 3D-printed design is an awfully quick-working and effective way to stamp a design onto a shirt.

Plain PLA stamp with bleach gives a slightly distressed look to this design.

While conceptually simple, the details make the difference. Spraying bleach onto the stamp surface helps get even coverage, and having the stamp facing “up” and lowering the shirt onto the stamp helps prevent bleach from running where it shouldn’t. Prompt application of hot air with a heat gun (followed by neutralizing or flushing any remaining bleach by rinsing in plenty of cold water) helps keep the edges of the design clean and sharp.

We wondered if combining techniques with some of the tips on how to 3D print ink stamps would yield even better results. For instance, we notice the PLA stamp (used to make the design in the images here) produces sharp lines with a slightly “eroded” look overall. This is very much like the result of inking with a stamp printed in PLA. With a stamp printed in flex filament, inking gives much more even results, and we suspect the same might be true for bleach.

Of course, don’t forget that it’s possible to 3D print directly onto fabric if you want your designs to be a little more controlled (and possibly in multiple colors). Or, try silkscreening. Who knew there were so many options for putting designs onto shirts? If you try it out and learn anything, let us know by sending in a tip!

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Illustrated Kristina with an IBM Model M keyboard floating between her hands.

Keebin’ With Kristina: The One With The SEGA Pico Keyboard

February 10, 2025 by 3 Comments

It’s been a minute since I featured a tiny keyboard, and that’s okay. But if you want to get your feet wet in the DIY keyboarding community, making a little macro pad like [Arnov Sharma]’s Paste Pal is a great place to start.

A macro pad with five switches and a small OLED display.
Image by [Arnov Sharma] via Hackaday.IO
This is a follow-up to his original Paste Pal, which only had two buttons for copy and paste plus an OLED display. This updated version does three more things thanks to a total of five blue (!) switches. The selected command shows up on the screen so you know what you’ve done.

Right now, [Arnov] has the Paste Pal set up to do Copy, Paste, Enter, Scroll Up, and Scroll Down, but changing the assignments is as easy as updating a few lines of code.

Paste Pal Mk. II is at heart a Seeed Xiao SAMD21, which in this case is programmed in Arduino. If you want to make things easier on yourself, you could program it in CircuitPython instead, although [Arnov] includes the Arduino code in his excellent build guide.

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Tiny Mouse Ring Uses Prox Sensors

February 10, 2025 by 11 Comments

A traditional computer mouse typically fits in the palm of your hand. However, with modern technology, there’s no need for mice to be so large, as demonstrated by [juskim]’s neat little mouse ring. Check it out in the video below.

The concept is simple—it’s a tiny mouse that sits neatly on the end of one of your fingers. You then get the slightly surreal experience of pointing on your computer just by moving a single finger instead of your whole hand.

The project uses a typical optical mouse sensor for movement, as you might expect. However, there are no conventional switches for the left and right mouse buttons. Instead, [juskim] realized a more compact design was possible by using proximity sensors instead. The sensors detect the presence of his fingers on either side of the ring mouse. When one of the fingers is lifted, the absence of the finger triggers a mouse click, either left or right, depending on the finger.

The build started with junk box parts, but hooking up an Arduino Pro Micro dev board and other modules proved too cumbersome to use effectively. Instead, the build relies on an ATTO board, a tiny PCB featuring the same ATmega32U4 microcontroller. Similarly, the build relies on tiny proximity sensors from STM to fit in the “ring” form factor. It’s all wrapped up in a 3D-printed enclosure that fits snugly on the user’s finger.

We’ve seen some other neat mouse rings before, too. Or, if you want something really different, grab some keychains and make a 6DOF mouse.

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How Magnetic Fonts Twisted Up Numbers And Saved Banking Forever

February 10, 2025 by 48 Comments

If you’ve ever looked at the bottom of a bank check, you probably glanced over some strangely formed numbers? If you’re a fan of science fiction or retro computers, you’ve probably spotted the same figures on any number of books from the 1980s. They’re mostly readable, but they’re chunky and thin in places you don’t expect.

Those oddball numerals didn’t come from just anywhere—they were a very carefully crafted invention to speed processing in the banking system. These special fonts were created to be readable both by humans and machines—us with our eyes, and the computers with magnetic sensors. Let’s explore the enigmatic characters built for Magnetic Ink Character Recognition (MICR). Continue reading “How Magnetic Fonts Twisted Up Numbers And Saved Banking Forever” →

Basically, It’s BASIC

February 10, 2025 by 36 Comments

The BASIC language may be considered old-hat here in 2025, and the days when a computer came as a matter of course with a BASIC interpreter are far behind us, but it can still provide many hours of challenge and fun. Even with our love of all things 8-bit, though, we’re still somewhat blown away by [Matthew Begg]’s BASIC interpreter written in 10 lines of BASIC. It’s an entry in the BASIC 10-liner competition, and it’s written to run on a Sinclair ZX Spectrum.

The listing can be viewed as a PNG file on the linked page. It is enough to cause even the most seasoned retrocomputer enthusiasts a headache because, as you might expect, it pushes the limits of the language and the Sinclair interpreter.  It implements Tiny Basic as a subset of the more full-featured BASICs, and he’s the first to admit it’s not fast by any means. He gives a line-by-line explanation, and yes, it’s about as far away from the simple Frogger clones we remember bashing in on our Sinclairs as it’s possible to get.

We love it that there are still boundaries to be pushed, even on machines over four decades old, and especially that this one exceeds what we thought was a pretty good knowledge of Sinclair BASIC. Does this language still have a place in the world? We always look forward to the BASIC 10-liner competition.

Header: background by Bill Bertram, CC BY-SA 2.5.

Flip Flops Make Great Soft Switches

February 10, 2025 by 46 Comments

Mechanical switches are pretty easy to understand—the contacts touch, the current flows, and Bob is, presumably, your uncle. But what about soft switches? Well, they’re not that difficult to understand either, as explained by [EDN].

You can build a touch switch quite easily with old-school chips.

The traditional softswitch takes input from a momentary single-pole pushbutton and lets you press to toggle power on and off. This operation is easy to achieve with a simple flip-flop constructed with old-school logic to create a “bistable” circuit. That means it will happily remain stable in one of two states unless you do something to make it switch.

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