[Stephen Carey] wanted to spruce up his car with sound reactive LEDs but couldn’t quite find the right project online. Instead, he wound up assembling a custom bass reactive LED display using an ESP32.
The entirety of the build is minimal, consisting of a GY-MAX4466 electret microphone module, a KY-040 encoder for some user control and an ESP32 attached to a Neopixel strip. The only additional electronic parts are some passive resistors to limit current on the data lines and a capacitor for power line noise suppression. [Stephen] uses various enclosures from Thingiverse for the microphone, rotary encoder and ESP32 box to make sure all the modules are protected and accessible.
The magic, of course, is in the software, with the CircuitPythyon ulab library used to do the heavy lifting of creating the spectrogram and frequency filtering. [Stephen] has made the code is available on GitHub for those wanting to take a closer look.
It wasn’t very long ago that sound reactive LEDs used to be a heavy lift, requiring optimized FFT libraries or specialized components to do the spectrogram. With faster and cheaper microcontroller boards, we’re seeing many great projects, like the sensory bridge or Raspberry Pi driven LED spectrogram, that can now take spectrograms and Fourier transform calculations as basic infrastructure to build on top of them. We’re happy to see [Stephen] leverage the ESP32’s speed and various circuit Python libraries to create a very cool LED car hack.
[Jeff Lau]’s Mitsubishi 3000GT comes with all the essential features you’d expect in a fancy sports car from 1993: pop-up headlights, movable spoilers, and a fully-functional telephone handset in the center console. The phone was fully functional until North America’s first-generation AMPS cellular network was shut down back in 2008, since then, it hasn’t done much but show “NO SVC” on the display. That is, until [Jeff] decided to build a Bluetooth adapter that lets it connect to a modern smartphone.
The easy solution would have been to simply connect the handset’s speaker and microphone to a standard Bluetooth headset, but that would have destroyed the 1990s aesthetic it had going on. So what [Jeff] did instead was construct a plug-in module that hooks up to the phone’s base station in the trunk and communicates directly with all the existing systems. That way, the phone works in exactly the same way it always did: the radio is automatically muted during calls, the buttons on the steering column work as expected, and you can even dial and store numbers using the buttons on the handset.
It took a lot of reverse-engineering to figure out the technical details of the DiamondTel Model 92 that came with the car as a factory option. [Jeff] helpfully documented all of his findings on the project’s GitHub page, making it easy for anyone with a similar system to implement their own upgrades. The main components of the upgrade kit are a BM62 Bluetooth module that connects to a modern phone, a PIC18F27Q43 microcontroller to implement the car phone’s interface and menus, and several analog chips to process the audio. All of these are mounted on a piece of prototype board and housed in a standard plastic enclosure that neatly fits on top of the existing equipment in the trunk.
While the hardware mod is a pretty neat job already, the real strength of this project is in the software. [Jeff] worked hard to implement all relevant features and mimic the original interface as much as possible, even using 1G phone test equipment to simulate incoming calls from the long-gone network. He also added menu features to enable Bluetooth pairing, use voice assistants, and even play games including versions of Snake and Tetris stripped down to match the handset display’s constraints.
More than three years have passed since Tesla announced its Cybertruck, and while not a one has been delivered, the first Tesla truck, Truckla, has kept on truckin’. [Simone Giertz] just posted an update of what Truckla has been up to since it was built.
[Giertz] and friend’s DIT (do-it-together) truck was something of an internet sensation when it was revealed several months before the official Tesla Cybertruck. As with many of our own projects, while it was technically done, it still had some rough edges that kept it from being truly finished, like a lack of proper waterproofing or a tailgate that didn’t fold.
Deciding enough was enough, [Giertz] brought Truckla to [Marcos Ramirez] and [Ross Huber] to fix the waterproofing and broken tailgate while she went to [Viam Labs] to build Chargla, an Open Source charging bot for Truckla. The charging bot uses a linear actuator on a rover platform to dock with the charging port and is guided by a computer vision system. Two Raspberry Pis power handle the processing for the operation. We’re anxious to see what’s next in [Giertz]’s quest of “picking up the broken promises of the car world.”
Dash cameras are handy as they provide a video recording of interactions on the road. However, their utility comes from the fact that they are always recording while driving. This always-on means power draw. [Kuzysk] took it upon himself to cut that power draw by a factor of almost 70x.
He found his existing dash cam from MiVue consumed 3.5mA in idle which works out to be a whole amp-hour every 12 days. The custom version takes just 50uA which means it will draw an amp-hour in two years. The brains of the chip are formed by an ATmega328 and an LM2596M, which is a simple step-down regulator. Interestingly, [Kuzysk] purchased clones and original chips and found that the cheaper clones had a lower switching frequency but a much lower power draw. Programming an Arduino bootloader onto the board is fairly straightforward and [Kuzysk] kindly provides his code. It can detect the ACC voltage that’s on when the engine is on and is powered by a permanent 12v connection to the battery.
The 3D printing revolution has transformed a lot of industries, but according to [Insider Business] the car industry still uses clay modeling to make life-sized replicas of new cars. The video below shows a fascinating glimpse of the process of taking foam and clay and making it look like a real car. Unlike the old days, they do use a milling machine to do some rough work on the model, but there’s still a surprising amount of manual work involved. Some of the older film clips in the video show how hard it was to do before the CNC machines.
The cost of these models isn’t cheap. They claim that some of the models have cost $650,000 to create. We assume most of that is in salaries. Some models take four years to complete and a ton of clay.
Many EVs can charge 80% of their battery in a matter of minutes, but for some applications range anxiety and charge time are still a concern. One possible solution is an embedded electrical rail in the road like the [eRoadArlanda] that Sweden unveiled in 2016.
Overhead electrical wires like those used in trolleys have been around since the 1800s, and there have been some tests with inductive coils in the roadway, but the 2 km [eRoadArlanda] takes the concept of the slot car to the next level. The top of the rail is grounded while the live conductor is kept well underground beneath the two parallel slots. Power is only delivered when a vehicle passes over the rail with a retractable contactor, reducing danger for pedestrians, animals, and other vehicles.
One of the big advantages of this technology being in the road bed is that both passenger and commercial vehicles could use it unlike an overhead wire system that would require some seriously tall pantographs for your family car. Testing over several Swedish winters shows that the system can shed snow and ice as well as rain and other road debris.
Unfortunately, the project’s website has gone dark, and the project manager didn’t respond when we reached out for comment. If there are any readers in Sweden with an update, let us know in the comments!
The design is simple. It relies on 3D printing a replacement bezel for the Mazda Miata’s stock round air vents. This bezel is designed to hold a NeoPixel ring from Adafruit. When built with the optional laser-cut diffuser, the parts have a near-stock look when the LEDs are turned off. It’s a classy, stealthy mod – exactly the sort of thing Miata owners need but never seem to have! (Author Note: don’t be mad, I was once one of you!)
With 24 addressable RGB LEDs, it’s possible to display all kinds of data by turning the LEDs on and off and varying the colors. For example, you could readily build a boost gauge that turns on more LEDs at higher boost pressure. It could then be set up to flash red in the event that you surpass safe thresholds. [ktanner] hasn’t specified any particular microcontroller for the setup — but just about any part you like can be used to drive NeoPixels, after all.