Train Speed Signaling Adapted For Car

September 11, 2024 by 33 Comments

One major flaw of designing societies around cars is the sheer amount of signage that drivers are expected to recognize, read, and react to. It’s a highly complex system that requires constant vigilance to a relatively boring task with high stakes, which is not something humans are particularly well adapted for. Modern GPS equipment can solve a few of these attention problems, with some able to at least show the current speed limit and perhaps an ongoing information feed of the current driving conditions., Trains, on the other hand, solved a lot of these problems long ago. [Philo] and [Tris], two train aficionados, were recently able to get an old speed indicator from a train and get it working in a similar way in their own car.

The speed indicator itself came from a train on the Red Line of the T, Boston’s subway system run by the Massachusetts Bay Transportation Authority (MBTA). Trains have a few unique ways of making sure they go the correct speed for whatever track they’re on as well as avoid colliding with other trains, and this speed indicator is part of that system. [Philo] and [Tris] found out through some reverse engineering that most of the parts were off-the-shelf components, and were able to repair a few things as well as eventually power everything up. With the help of an Arduino, an I/O expander, and some transistors to handle the 28V requirement for the speed indicator, the pair set off in their car to do some real-world testing.

This did take a few tries to get right, as there were some issues with the power supply as well as some bugs to work out in order to interface with the vehicle’s OBD-II port. They also tried to use GPS for approximating speed as well, and after a few runs around Boston they were successful in getting this speed indicator working as a speedometer for their car. It’s an impressive bit of reverse engineering as well as interfacing newer technology with old. For some other bits of train technology reproduced in the modern world you might also want to look at this recreation of a train whistle.

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Fast 3D Printing With A Polar, Four Quadrant Custom Machine

August 26, 2024 by 14 Comments

3D printing is all well and good for making low numbers of units, so long as they’re small enough to print in a reasonable time, but what if you want to go really big? Does a 35-hour print time sound like a fun time? Would it even make it that long? [Nathan] from Nathan Build Robots didn’t fancy the wait, so they embarked on a project to build a huge parallel 3D printer with four independent print heads. Well, kind of. Continue reading “Fast 3D Printing With A Polar, Four Quadrant Custom Machine” →

A Tiny Knob Keeps You In Control

August 11, 2024 by 35 Comments

There are many forms of human interface device beyond the ubiquitous keyboard and mouse, but when it comes to fine-tuning a linear setting such as a volume control there’s nothing quite like a knob. When it comes to peripherals it’s not the size that matters, as proven by  [Stefan Wagner] with the Tiny Knob. It’s a very small PCB with a rotary encoder and knob, an ATtiny85, a USB port, and not much else.

It uses the V-USB software implementation of USB HID, and should you have a need for a Tiny Knob of your own you can find all the files for it in a GitHub repository. There’s even a very professional-looking 3D-printed enclosure for the finishing touch. We like this project for its simplicity, and we think you might too.

Over the years we’ve brought you more than one knob, they appear to be a popular subject for experimentation. If you’re up for more, have a look at this one.

Mapping The Human Brain And Where This May Lead Us

May 23, 2024 by 31 Comments

In order to understand something, it helps to observe it up close and study its inner workings. This is no less true for the brain, whether it is the brain of a mouse, that of a whale, or the squishy brain inside our own skulls. It defines after all us as a person; containing our personality and all our desires and dreams. There are also many injuries, disorders and illnesses that affect the brain, many of which we understand as poorly as the basics of how memories are stored and thoughts are formed. Much of this is due to how complicated the brain is to study in a controlled fashion.

Recently a breakthrough was made in the form of a detailed map of the cells and synapses in a segment of a human brain sample. This collaboration between Harvard and Google resulted in the most detailed look at human brain tissue so far, contained in a mere 1.4 petabytes of data. Far from a full brain map, this particular effort involved only a cubic millimeter of the human temporal cortex, containing 57,000 cells, 230 millimeters of blood vessels and 150 million synapses.

Ultimately the goal is to create a full map of a human brain like this, with each synapse and other structures detailed. If we can pull it off, the implications could be mind-bending.

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A black PCB with a cellular modem board piggy backed on top. It has a micro-USB and DB-type connector on the end facing the camera.

Open Vehicle Monitoring System Is The Window To Your EV’s Soul

January 25, 2024 by 14 Comments

Electric cars have more widgets than ever, but manufacturers would rather you don’t have direct access to them. The Open Vehicle Monitoring System intends to change that for the user. [via Transport Evolved]

As car manufacturers hoover up user data and require subscriptions for basic features, it can be a frustrating time to make such a big purchase. Begun in 2011, OVMS now interfaces with over a dozen different EVs and gives you access to (or helps you reverse engineer) all the data you could want from your vehicle. Depending on the vehicle, any number of functions can be accessed including remote climate start or cell-level battery statistics.

The hardware connects to your car’s OBDII port and uses an ESP32 microcontroller connected to a  SIMCOM SIM7600G modem (including GPS) to provide support for 3 CAN buses as well as Wi-Fi and Bluetooth connections. This can be particularly useful for remote access to data for vehicles that can no longer phone home via their originally included cellular modems as older networks shut down.

Do you wish EVs weren’t so complicated? Read our Minimal Motoring Manifesto.

ESP32 Used As Wireless CAN Bus Reader

November 22, 2023 by 34 Comments

The CAN bus, accessible through the OBD-II port, is the channel that holds all the secrets of the modern automobile. If you want to display those for your own perusal, you might consider this nifty tool from [EQMOD].

Yes, it’s an OBD-II dongle that you can build using an ESP32 WROVER module. It’s designed to read a car’s CAN bus communications and display them on a self-hosted web page, accessible over WiFi. The build relies on the dual-core nature of the ESP32, with the first core handling CAN bus duties via the SN65HVD230 CAN bus transceiver chip. The second core is responsible for hosting the web page. Data received via the CAN bus is pushed to the web user interface roughly every 60 to 100 milliseconds or so for information like RPM and speed. Less time-critical data, like temperatures and voltages, are updated every second.

It’s a neat little thing, and unlike a lot of dongles you might buy online, you don’t need to install some dodgy phone app to use it. You can just look at the ESP32’s web page for the data you seek. The graphics may be a little garish, but they do the job of telling you what’s going on inside your car. Plus, you can always update them yourself.

Getting to grips with the CAN bus is key if you want to diagnose or modify modern vehicles. Meanwhile, if you’ve been cooking up your own electronic vehicular hacks, don’t hesitate to drop us a line!

The Magic Of A Diode Sampler To Increase Oscilloscope Bandwidth

September 30, 2023 by 25 Comments

Making an oscilloscope is relatively easy, while making a very fast oscilloscope is hard. There’s a trick that converts a mundane instrument into a very fast one, it’s been around since the 1950s, and [CuriousMarc] has a video explaining it with an instrument from the 1960s. The diode sampler is the electronic equivalent of a stroboscope, capturing parts of multiple cycle of a waveform to give a much-slowed-down representation of it on the screen. How it works is both extremely simple, and also exceptionally clever as some genius-level high-speed tricks are used to push it to the limit. We’ve put the video below the break.

[Marc] has a Keysight 100 MHz ‘scope and the sampler allows him to use it to show 4 GHz. Inside the instrument is a pair of sample-and-hold circuits using fast diodes as RF switches, triggered by very low-rise-time short pulses. Clever tricks abound, such as using the diode pair to cancel out pulse leakage finding its way back to the source. To complete this black magic, an RF-tuned stub is utilized to help filter the pulses and further remove slower components.

It’s slightly amusing to note that the Keysight 100 MHz ‘scope is now “slow” while the early sampling ‘scopes had their “fast” capabilities in that range. The same technique is still used today, in fact, you probably have one on your bench.

The sampler he’s showing us is an accessory for another instrument we’ve previously shown you his work with.

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