Custom Packet Sniffer Is A Great Way To Learn CAN

July 2, 2020 by Adil Malik 18 Comments

Whilst swapping out the stereo in his car for a more modern Android based solution, [Aaron] noticed that it only utilised a single CAN differential pair to communicate with the car as opposed to a whole bundle of wires employing analogue signalling. This is no surprise, as modern cars invariably use the CAN bus to establish communication between various peripherals and sensors.

In a series of videos, [Aaron] details how he used this opportunity to explore some of the nitty-gritty of CAN communication. In Part 1 he designs a cheap, custom CAN bus sniffer using an Arduino, a MCP2515 CAN controller and a CAN bus driver IC, demonstrating how this relatively simple hardware arrangement could be used along with open source software to decode some real CAN bus traffic. Part 2 of his series revolves around duping his Android stereo into various operational modes by sending the correct CAN packets.

These videos are a great way to learn some of the basic considerations associated with the various abstraction layers typically attributed to CAN. Once you’ve covered these, you can do some pretty interesting stuff, such as these dubious devices pulling a man-in-the-middle attack on your odometer! In the meantime, we would love to see a Part 3 on CAN hardware message filtering and masks [Aaron]!

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Mini Library For Kids Gets Blinky Lights And Solar Upgrade

June 28, 2020 by Donald Papp 1 Comment

Reading is big in Québec, and [pepelepoisson]’s young children have access to a free mini library nook that had seen better days and was in dire need of maintenance and refurbishing. In the process of repairing and repainting the little outdoor book nook, he took the opportunity to install a few experimental upgrades (link in French, English translation here.)

The mini library pods are called Croque-Livres, part of a program of free little book nooks for children across Québec (the name is a bit tricky to translate into English, but think of it as “snack shack, but for books” because books are things to be happily devoured.)

After sanding and repairs and a few coats of new paint, the Croque-Livres was enhanced with a strip of WS2812B LEDs, rechargeable battery with solar panel, magnet and reed switch as door sensor, and a 3.3 V Arduino to drive it all. [pepelepoisson]’s GitHub repository for the project contains the code and CAD files for the 3D printed pieces.

The WS2812B LED strip technically requires 5 V, but as [pepelepoisson] found in his earlier project Stecchino, the LED strip works fine when driven directly from a 3.7 V lithium-polymer cell. It’s not until around 3 V that it starts to get unreliable, so a single 3.7 V cell powers everything nicely.

When the door is opened, the LED strip lights up with a brief animation, then displays the battery voltage as a bar graph. After that, the number of times the door as been opened is shown on the LED strip in binary. It’s highly visual, interactive, and there’s even a small cheat sheet explaining how binary works for anyone interested in translating the light pattern into a number. How well does it all hold up? So far so good, but it’s an experiment that doesn’t interfere at all with the operation of the little box, so it’s all good fun.

Calcuino Is An Arduino Calculator

June 28, 2020 by Al Williams 4 Comments

All by itself, a calculator based on an Arduino isn’t necessarily very novel. However, [Danko Bertović] of Volos Projects has a nice board that, of course, looks like a calculator. There are 16 keys and an LED display. But it seems to us the real value would be using this as a base for other projects.

As an inexpensive development board, it’s handy to have a simple processor with a keyboard and a display. There’s some extra I/O pins and the first example in the video below shows using the setup as a simple organ, for example. We’d love to see an option to replace the LED with an LCD and maybe even some different CPU options, as well.

The board is essentially an Arduino with a standard USB to serial chip and a MAX7219 display driver. Of course, you could breadboard up all of these things, but it wouldn’t be as neat looking. One unusual thing about the keyboard is that it is not multiplexed. Each button has a label that indicates what Arduino pin it connects with. So key 6 connects to pin 6 and pin A2 connects to the key marked =/A2.

With the availability of inexpensive PC boards, we’re seeing many nice designs out there that would be easy to repurpose for other things. For example, we thought this board would easily run the Kim Uno, with some modifications to the I/O routines. Might even be able to work out a clone of an even older computer to fit on the board.

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DIY TV-B-Gone Is A-OK

June 25, 2020 by Kristina Panos 49 Comments

Where won’t they put a TV these days? We’ve even seen one creeping behind semi-transparent mirror film in the ladies’ room of a sports bar, though that one didn’t last long. Up until that moment, we had never wished so hard for a TV-B-Gone, especially one as small and powerful as this DIY version by [Shane].

The best thing about [Shane]’s DIY TV-B-Gone is the strength of signal, though the size is nothing to sneeze at. That’s a 10-watt array or IR LEDs out of a security camera, and you can see how much brighter it is than a single IR LED in the video after the break.

Packed inside this minty enclosure is an Arduino Nano, which holds all the TV power-off codes known to hackers and fires them off in quick succession. [Shane] salvaged a MOSFET from an electronic speed controller to drive that LED array, and there’s a voltage booster board to raise the 3.7V lithium battery to 5V. [Shane] hasn’t really had the chance to test this out in public what with the global pandemic and all, but was able to verify a working distance of 40 feet inside the house.

Don’t care for such a raw look? Hide your zapper inside a toy, like this sonic screwdriver version.

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Tracked Robot Makes Sand Drawings

June 24, 2020 by Al Williams 6 Comments

[Ivan] seems to enjoy making 3D printed vehicles with tracks. His latest one uses 50 servo motors to draw patterns in the sand at the beach. You can see it work in the video below. Well, more accurately you can see it not work and then work as the first iteration didn’t go exactly as planned.

An Arduino Mega 2560 provides the brains and the whole unit weighs in at almost 31 pounds, including the batteries. We didn’t see Ivan’s design files, although it wouldn’t be hard to do your own take on the robot.

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Score Big Against Boredom With Tabletop Bowling

June 21, 2020 by Kristina Panos 18 Comments

Bowling has been around since ancient Egypt and continues to entertain people of all ages, especially once they roll out the fog machine and hit the blacklights. But why pay all that money to don used shoes and drink watered-down beer? Just build a tabletop bowling alley in your spare time and you can bowl barefoot if you want.

Those glowing pins aren’t just for looks — the LEDs underneath them are part of the scoring system. Whenever a pin is knocked out of its countersunk hole, the LED underneath is exposed and shines its light on a corresponding light-dependent resistor positioned overhead. An Arduino Uno keeps track of of the frame, ball number, and score, and displays it on an LCD.

The lane is nearly six feet long, so this is more like medium-format bowling or maybe even skee-bowling. There are probably a number of things one could use for balls, but [lainealison] is using large ball bearings. Roll past the break to see it in action, but don’t go over the line!

Can’t keep your balls out of the gutter? Build a magic ball and make all wishful leaning more meaningful as you steer it down the lane with your body.

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Message In A Bottle: Bicycle Trailer On A Mission

June 19, 2020 by Sven Gregori 18 Comments

Graffiti is a controversial subject, and whether you see it as art or vandalism usually depends where and how you come across it. From the scribbled tag on a house wall, to highly sophisticated murals, they tend to have one thing in common though: making a statement — whether that’s political, showing appreciation, or a simple “I was here”. [Sagarrabanana] had his own statement to make, but chose a less permanent way to express himself with his type of graffiti.

Unhappy about the lack of dedicated cycle lanes in his area, he built an automatic, Arduino-controlled water dispensing bicycle trailer, writing his message on every street he rides on. The build is documented in a video, and shown in action in another one — which are both in Spanish (and also embedded after the break), but pictures are worth their thousand words in any language.

Inspired by persistence of vision (POV), where moving LEDs sync up their blinking to give the illusion of a static image, [Sagarrabanana] transformed the concept to water on a road using an array of solenoids attached to a water tank. Each solenoid is controlled by a relay, and a predefined font determines when to switch each relay — the same way pixels on a display would be set on or off, except small amounts of water are squirted out as the bicycle is moving along. The message itself is received via serial Bluetooth module, and can be easily modified for example from a phone. To adjust the water dispensing to the cycling speed, the whole system is synced to a magnetic switch mounted to one of the trailer’s wheels, so you could theoretically take it also with you on a run.

Time will tell if [Sagarrabanana]’s mission has the success he hopes for, but there’s no doubt the trailer will attract attention anywhere he goes. Well, we wish him all the best to get the message through without requiring a too drastic alternative as writing medium. Although, we’ve seen a graffiti robot that uses chalk spray in the past, so there’s certainly room for a not-too-permanent upgrade if needed.

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