Keeping A Mazda’s Radio On After The Engine Shuts Off

November 22, 2023 by 51 Comments

Have you ever pulled into a car park with your favorite song blaring, only to lament the fact that the music cut out when you stopped the engine? Some modern cars are smart enough to keep the radio on until you open the door. [ssh16] decided to hack that very functionality into their Mazda MX-5.

The device uses a microcontroller to read the CAN bus of the vehicle. The microcontroller also has the ability to keep the vehicle’s ACC (accessory) relay energized at will. Thus, when the engine is turned off, the microcontroller keeps the ACC relay on, maintaining power to the stereo and infotainment system. Then, after ten minutes, or when it receives a CAN message that the driver’s door has been opened, it cuts power to the relay, shutting the accessories off. It’s a simple build, but one that [ssh16] executed cleanly. By putting the microcontroller on a neat PCB with a harness that can clip into the stock Mazda one, it’s possible to install the hack without needing to cut any wires. Plus, with a small modification, it was even possible to use the same hack with a Mazda CX-5.

Whether you’re jamming out to a cool song, or you just want to finish a phone call over Bluetooth, it’s a nifty feature to have in a vehicle. We’ve seen some other neat infotainment hacks before, too. Video after the break.

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A Brand-New Antique Radio

November 22, 2023 by 17 Comments

This beautiful little radio may look like an art deco relic from a hundred years ago, but it is actually from 2023. When [Craig Lindley] first saw this design on these very pages a few years ago, he just had to build one eventually. Turns out, all he had to do wait until he bought a laser cutter.

Built with hardware on hand, this radio runs on an ESP32 WROOM and uses an Adafruit VS1053 CODEC breakout. Song information is displayed on an SPI LCD display, and output comes via a 1/8″ jack. It can play songs streamed from Internet radio stations, [Craig]’s website, or directly from an SD card.

The lovely cabinet is made from 1/8″ Baltic birch, with a living hinge for a roof and sides. The amber shellac goes a long way toward establishing the antique aesthetic.

Not content with this cute radio, [Craig] went ahead and built a speaker system to go with it out of a pair of small, external laptop speakers. [Craig] says this project had a lot of ups and downs, but we are quite happy to see it come to fruition.

Do you have an antique radio you’d like to restore? Be sure to check out our guide.

The Ghost Detector 9000 Is A Fun Spirit-Chasing Game

November 21, 2023 by 1 Comment

Halloween may have come and gone for another year, but we’re still finding neat spooky projects lurking out on the Interwebs. Case in point, the Ghost Detector 9000 from [Jules].

Effectively, what you’re looking at here is a fun interactive ghost-detecting game. It consists of a Raspberry Pi Zero hooked up with an IMU sensor that can detect the rig’s movement and orientation. As the user moves the Ghost Detector 9000 around, it outputs lights and sound when it’s aimed at a so-called “ghost-signal”. The user then pulls the trigger to “capture” the ghost. The whole rig is built inside a flashlight which presented a useful form factor for modification.

For those eager to dive into the nitty-gritty, [Jules] has shared the project files on GitHub. There’s some nifty stuff going on, like Rust code that interfaces with I2C devices hooked up to the Pi, and a sensor-fusion algorithm to make the most out of the data from the 9-axis IMU.

It’s a fun build that probably taught [Jules] a great deal along the way, even if it’s a game at heart. If you prefer to shoot zombies instead of capture ghosts, we’ve seen a build that lets you go hunting with a laser crossbow, too.

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A brown, wooden picture frame with a white matte holds a slightly pixelated photo of gaming miniatures. It is sitting on a wooden table.

A Colorful Take On The E-Ink Photo Frame

November 21, 2023 by 7 Comments

Everyone loves sharing photos, and with most pictures being taken on smartphones now, digital frames are more convenient than finding a photo printer. [Wolfgang Ziegler] used an e-ink screen to create a colorful digital picture frame.

Starting with a seven color e-ink HAT he’d forgotten he had, a spare Pi Zero, and analog photo frame, he pieced the parts together into a pretty slick, sunlight readable photo frame. [Ziegler] details how he set up the frame to display new images using the Pimoroni inky library. He set a fifteen minute refresh interval since the color e-ink display takes 30 seconds to refresh to keep it from looking weird too often.

With the holidays coming up, this might make a perfect gift for family that wants to see the latest from your travels without blasting it to the whole internet. We’ve covered a few different options from a lightweight ESP8266 build, to this one that can rotate, and even issues with some of the commercial options.

Building An Animated Turn Signal For The Mazda MX-5

November 21, 2023 by 37 Comments

Turn signals in most of the world are mandated to be a flashing orange light, distinct from other bulbs on a vehicle. However, there has been a trend in the modern era to go for fancier animated turn signals using great numbers of LEDs. [ssh16] decided to whip up a set of their own to suit their late-model Mazda MX-5.

Fully lit, the replacement is brighter than the original bulb by some margin.

While many builds go down the route of using addressable LEDs, [ssh16] instead went for garden variety OSRAM yellow LEDs in a 3×12 array, driven via a shift register. A small PIC microcontroller is then used to command the shift register to light the rows of LEDs in turn, generating the sequential lighting effect that sweeps from one side to the other. The LEDs are are installed on a 4″ board designed to install in place of the Mazda’s standard indicator bulb, with the animation spreading from the centerline of the vehicle out towards the direction of the turn.

It’s a fun build that modernizes the rear turn signals of the Mazda. We’ve seen some other neat turn signal builds before, too; it almost seems to be a trend amongst Mazda enthusiasts. Meanwhile, if you’ve built your own automotive lighting mods, don’t hesitate to send them in to the tipsline.

Simple CMOS Circuit Allows Power And Data Over Twisted-Pair Wiring

November 21, 2023 by 29 Comments

If you need to send data from sensors, there are plenty of options, including a bewildering selection of wireless methods. Trouble is, most of those protocols require a substantial stack of technology to make them work, and things aren’t much easier with wired sensors either. It doesn’t have to be that complicated, though, as this simple two-wire power-and-data interface demonstrates.

As with all things electronic, there are tradeoffs, which [0033mer] addresses in some detail in the video below. The basic setup for his use case is a PIC-based sensor — temperature, for this demo — that would be mounted in some remote location. The microcontroller needs to be powered, of course, and also needs to send a signal back to a central point to indicate whether the monitored location is within temperature specs. Both needs are accommodated by a single pair of wires and a tiny bit of additional circuitry. On one end of the twisted pair is a power supply and decoder circuit, which sends 9 volts up the line to power the PIC sensor. The decoder is based on a CD4538 dual monostable multivibrator, set up for an “on” time of one second. A trigger input is connected to the power side of the twisted pair going to the sensor, where a transistor connected to one of the PIC’s GPIO pins is set up to short the twisted pair together every half-second. Power to the PIC is maintained by a big electrolytic and a diode, to prevent back-feeding the controller. The steady 0.5-Hz stream of pulses from the sensor keeps resetting the timer on the control side. Once that stream stops, either through code or by an open or short condition on the twisted pair, the controller triggers an output to go high.

It’s a pretty clever system with very simple and flexible circuitry. [0033mer] says he’s used this over twisted-pair wires a couple of hundred feet long, which is pretty impressive. It’s limited to one bit of bandwidth, of course, but that might just be enough for the job. If it’s not, you might want to check out our primer on current-loop sensors, which are better suited for analog sensors but still share some of the fault-detection features.

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Computer Gear With — Um — Gears

November 21, 2023 by 10 Comments

Analog computers have been around in some form for a very long time. One very obvious place they were used was in military vehicles. While submarine fire computers and the Norden bombsight get all the press, [msylvain59] has a lesser-known example: an M13A1 ballistic computer from an M48 tank that he tears down for us in the video below.

The M48, known as a Patton, saw service from 1952 to 1987. Just looking at the mechanical linkage to the tank’s systems is impressive. But inside, it is clear this is a genuinely analog computer. The thing is built — quite literally — like a tank. What was the last computer you opened that needed a hammer? And inside, you’ll find gears, bearings, and a chain!

We don’t pretend to understand all the workings. These devices often used gears and synchros (or selsyns, if you prefer) to track the position of some external thing. But we are guessing there was a lot more to it than that. It’s probably an exciting process to see something like that designed from scratch.

We did think of the Norden when we saw this. Hard to imagine, but there were “general purpose” analog computers.

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