Hacked Auxiliary Port For A Car Stereo

hacked-auxiliary-port-car-stereo
We’re not sure if [Apachem25] is just lucky, or if installing Auxiliary ports on most car stereos is this easy. The dealership wanted $95 to put one in, but he managed to add a 3.5mm audio-in port to his car stereo for just a couple of bucks.

The connector on the back of his head unit is a 2×4 set of pins recessed in a protective plastic ring. It turns out that the audio connector cable for a PC CD-ROM drive has a 1×4 socket that is perfect for this. [Apachem25] simply clipped one of those cables in half and used both ends to interface with the Aux port. He found the pin-out for his particular model on the Internet. He needed a specific resistance value between two of the pins to get the deck to let him use the input. All that he needed was a quick bit of soldering. The left, right, and ground are brought around the side and soldered to an audio jack he added in the face plate of the unit.

If you’re still rockin’ the cassette deck our favorite automotive Bluetooth solution is still this one for a classic Beetle.

[via Reddit]

DisplayPort: Tapping The Altmode

Really, the most modern implementation of DisplayPort is the USB-C DisplayPort altmode, synonymous with “video over USB-C”, and we’d miss out if I were to skip it. Incidentally, our last two articles about talking USB-PD have given a few people a cool new toy to play with – people have commented on the articles, reached out to me for debugging help, and I’ve even seen people build the FUSB302B into their projects! Hot on the heels of that achievement, let’s reach further and conquer one more USB-C feature – one that isn’t yet openly available for us to hack on, even though it deserves to be.

For our long-time readers, it’s no surprise to see mundane capabilities denied to hackers. By now, we all know that many laptops and phones let you get a DisplayPort connection out of a USB-C port. Given that the USB-C specifications are openly available, and we’ve previously implemented a PD sink using those specifications, you’d expect that we could do DisplayPort with the same ease. Yet, the DisplayPort altmode specification is behind a VESA membership paywall, with a hefty pricetag – a practice of theirs that has been widely criticized, counter to their purpose as a standards organization and having resulted in some of their standards failing.

Not to worry, however – we can easily find an assortment of PDFs giving a high-level overview and some details of the DisplayPort altmode, and here’s my favorite! I also have a device running MicroPython with a FUSB302 chip connected, and a few DisplayPort altmode devices of mine that I can disassemble. This, turns out, is more than enough for us to reverse-engineer our way into an open-source DisplayPort altmode library!

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The Folly Of Adding An Auxiliary Audio Input To A Hyundai Sonata

Why auxiliary audio inputs haven’t been standard on automotive head units for decades is beyond us. But you can bet that if you’re looking at a low-priced sedan you’ll need to buy an entire upgrade package just to get an audio jack on the dash. [Jon W’s] Hyundai Sonata didn’t have that bells-and-whistles upgrade so he decided to pop his stereo out and add his own aux port.

A big portion of this hack is just getting the head unit out of the dash. This is made difficult on purpose as an anti-theft feature, but [Jon’s] judicious use of a butter knife seemed to do the trick. He lost some small bits along the way which were recovered with a Shish Kebab skewer with double-stick tape on the end.

With the head unit out, he opened the case and plied his professional Electrical Engineering skills to adding the input. Well, he meant to, but it turns out there’s no magic bullet here. The setup inside the unit offered no easy way to solder up an input that would work. Having done all of the disassembly he wasn’t going to let it go to waste. [Jon] grabbed a nice FM transmitter setup. He wired it up inside the dash and mounted the interface parts in the glove box as seen here.

It’s nice to know we’re not the only ones who sometimes fail at achieving our seemingly simple hacking goals. At least [Jon] was able to rally and end up with the functionality he was looking for.

Auxiliary Battery Pack For Field Operations

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Ham operator [Ken – wa4mnt] wrote us to share a small project that he uses nearly every time he goes out in the field. His portable sealed lead acid battery pack (PDF) always ensures that he has a 12v power source at his fingertips, both for fun as well as in emergency situations.

The battery pack is pretty simple, and includes a 12v, 17ah battery strapped into a light aluminum chassis which he fabricated. The battery is secured with zip ties, so it can easily be swapped out or replaced without much fuss. The frame also sports a tiltable 4w, 17.5v solar panel that keeps the battery topped off and ready to go at all times. He stuck a voltmeter to the top of the battery to keep an eye on things, and he employs a 10A fuse to make sure he doesn’t fry any sensitive radio components should something go wrong.

The battery pack is pretty compact when you think about it, and we imagine it would be great to have on hand for a wide array of outdoor activities. Even if you’re not into Ham field operations, it’s hard to argue with its usefulness during power outages.

[Ken] doesn’t appear to have any published plans for the chassis or the electronic portion of the pack, but we’re pretty sure he would share if asked.

Using A Cellphone LCD As Auxiliary Linux Display

[Neil] is driving this Siemens A60 LCD using a parallel port on his Linux box. He likes this module because it has an integrated LED back-light, controller IC, and the pads are large enough for a human to solder. He notes that the screen runs on 2.9V, which matches the forward voltage of the LEDs used as back-lights. This means it is possible to use one f the LEDs as a shunt to drop  incoming voltage down to a safe level for the controller. In fact, that’s what he did. The data lines are connected to the parallel port along with some current limiting resistors. The LEDs are connected with resistor calculated for maximum brightness, with the output from the LED used as the source voltage for the LCD controller chip.Whether you want to use one of these screens with a PC or something else, the code that [Neil] worked out should provide the information necessary to do so.

The Nokia cellphone LCD post inspired [Neil] to send in a tip about this project. If you’ve got well documented hacks that you’re just sitting on why not let us know about them?

Building A Gas-Powered Pressure Washer

While you can always buy the tools you need, there’s something to be said for the satisfaction gained when you pick up a tool you built yourself. [Workshop From Scratch] has built a following out of building his own gear, the latest of which involved putting together a gas-powered pressure washer.

The key to the build was to keep things completely self-contained. All the consumables – water, soap, and wax – are kept onboard the washer to avoid having to run hoses and so on. A small gas engine is the heart of the build, hooked up to a high-pressure water pump. It even comes complete with a starter motor, making it a certified luxury garden tool. It’s also hooked up to two tanks holding cleaning solutions for car washing purposes, which feed into the pump via an auxiliary port for mixing. It’s all assembled on a custom steel frame welded together from rectangular hollow sections.

It’s a build that demonstrates how you can use your skills to build tools that suit your workflow, rather than just putting up with whatever is available off-the-shelf. We’ve seen his work before, too – building other tools like this motorised plasma cutter. Video after the break.

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Hackaday Prize Entry: Tongue Vision

Visually impaired people know something the rest of us often overlooks: we actually don’t see with our eyes, but with our brains. For his Hackaday Prize entry, [Ray Lynch] is building a tongue vision system, that will help blind people to see through one of the human brain’s auxiliary ports: the taste buds.

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