CAN

52 Articles

A Dashboard Outside The Car

January 11, 2024 by 12 Comments

One of the biggest upsides of open communications standards such as CAN or SPI is that a whole world of vehicle hacking becomes available, from simple projects like adding sensors or computers to a car or even building a complete engine control unit from the ground up. The reverse is true as well; sensors and gauges using one of these protocols can be removed from a car and put to work in other projects. That’s the idea that [John] had when he set about using a vehicle’s dashboard as a information cluster for his home.

The core of the build is an Astra GTE dashboard cluster, removed from its host vehicle, and wired to an Arduino-compatible board, in this case an ESP32. The code that [John] wrote bit-bangs an SPI bus and after some probing is able to address all of the instrument gauges on the dashboard. For his own use at home, he’s also configured it to work with Home Assistant, where each of the gauges is configured to represent something his home automation system is monitoring using a bit mask to send data to specific dials.

While this specific gauge cluster has a lot of vehicle-specific instrumentation and needs a legend or good memory to tie into a home automation system without any other modification, plenty of vehicle gauges are more intuitive and as long as they have SPI they’d be perfect targets for builds that use this underlying software. This project takes a similar tack and repurposes a few analog voltmeters for home automation, adding a paper background to the meters to make them easier to read.

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Vehicle-to-Grid Made Easy

May 25, 2023 by 37 Comments

As electric cars continue to see increased adoption, one associated technology that was touted long ago that still hasn’t seen widespread adoption is vehicle-to-grid or vehicle-to-home. Since most cars are parked most of the time, this would allow the cars to perform load-levelling for the grid or even act as emergency generators on an individual basis when needed. While this hasn’t panned out for a variety of reasons, it is still possible to use an EV battery for use off-grid or as part of a grid tie solar system, and now you can do it without needing to disassemble the battery packs at all.

Normally when attempting to use a scrapped EV battery for another use, the cells would be removed from the OEM pack and reorganized to a specific voltage. This build, however, eliminates the need to modify the packs at all. A LilyGO ESP32 is used to convert the CAN bus messages from the battery pack to the Modbus communications protocol used by the inverters, in this case a Fronius Gen24, so the inverter and battery can coordinate energy delivery from one to the other automatically. With the hard part out of the way, the only other requirements are to connect a high voltage DC cable from the battery pack to the inverter.

[Dala], the creator of this project, has taken other steps to ensure safety as well that we’d recommend anyone attempting to recreate this build pays close attention to, as these battery packs contain an extremely large amount of energy. The system itself supports battery packs from Nissan Leafs as well as the Tesla Model 3, which can usually be found for comparably low prices. Building battery energy storage systems to make up for the lack of commercially-available vehicle-to-home systems isn’t the only use for an old EV battery, though. For example, it’s possible to use Leaf batteries to triple the range of other EVs like [Muxsan] did with this Nissan van.

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A Smart Home That CAN Do It All

March 15, 2023 by 41 Comments

In an ideal smart home, the explosion of cheap WiFi and Bluetooth chips has allowed hundreds of small wireless devices to control the switches, lights, and everything else required for a “smart home” at a relatively low price. But what if you don’t want hundreds of internet-connected devices in your home polluting the wireless spectrum and allowing potential security holes into your network? If you’re like [Lucas Teske], you might reach for something wired and use cheap and (currently) available Raspberry Pi Picos to create PicoHome.

The unique twist of PicoHome is that it uses a CAN bus for communication. One of [Lucas’] goals was to make the boards easily swappable when hardware failed. This meant board-to-board communication and protocols like I2C were susceptible to noise (every time a relay triggered, the bus would lock up briefly). The CAN bus is designed to work in an electrically noisy environment.

There are two parts to the system: pico-relay and pico-input. The first connects to a 16 relay board and can control 16 different 24 V relays. The second has 16 optoisolators to read from 12 V to 24 V switches and various buttons throughout the house. These can be placed in a giant metal box in a central wiring location and not worry about it.

The firmware and board files are all released under an Apache 2.0 license, but the CAN2040 library this project relies on is under GPL. We covered the CAN2040 library when it was first released, and it’s lovely to see it being used for something entirely unexpected.

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All Aboard The Garbage Express

January 2, 2023 by 39 Comments

Cog railways are a somewhat unusual way of train locomotion, typically only installed when a train needs to climb steep terrain. Any grade above about 10% needs the extra traction since the friction between the wheels and rails won’t be enough to push the train forward or keep it from falling backwards. Even without a steep hill to climb, sometimes a cog railway is necessary for traction as [Max Maker] discovered while building a train for his garbage cans.

The build started out as a way to avoid having to wheel his seven waste bins to the curb every month. Originally he built a more standard railway with a simple motor to drive the train, but he quickly realized that there wasn’t enough grip even when using plastic wheels, even though this track follows fairly flat terrain. Since the rail is built out of steel he quickly welded up a rack-and-pinion system to one of the rails. The build goes through many iterations before he finally settles on a design that solves the problem, and it includes several other features as well such as remote control and a spring-loaded automatic charger for the train at its station in the back yard.

While we always appreciate the eccentricity of those who would automate a relatively simple task that only happens once a month, [Max Maker] hopes to build this into a commercial product aimed at the elderly or disabled who would really benefit from a reliable, semi-automatic system that takes their trash bins to the curb for them. And, if your system only involves a single trash can, there are other ways of automating the task of taking the garbage to the curb.

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This ESP32 CAN!

October 10, 2022 by 15 Comments

Since modern cars use the CAN bus for so many of their functions, it’s unsurprising that it’s a frequent object of interest for those in our community. Some people go no further than commercial plug-in analysers, while others build their own CAN devices. This is what [Magnus Thomé] has done, with his RejsaCAN microcontroller board.

It’s a small PCB with an onboard CAN interface from an ESP32-S3 and a car-friendly power supply circuit, and perhaps most importantly, it has an auto-shutdown feature to prevent battery drain. Software-wise it’s a blank piece of paper for the user to roll their own application, but since the ESP32 is supported by the Arduino ecosystem, there are libraries that make talking CAN as easy as it can be.

[Magnus] has a list of potential applications for the board, many of which take advantage of the ESP’s wireless capabilities. So far, [Magnus] has hooked it up to an LCD display, but we can see so many other useful things coming out powered by something like this.

You haven’t tried playing with your car’s CAN bus yet? Maybe you should read this to whet your appetite.

Part of a picture showing all kinds of different CAN devices in a car

CAN Peripheral For RP2040, Courtesy Of PIO

July 9, 2022 by 31 Comments

[Kevin O’Connor] writes to us about his project, can2040 – adding CAN support to the RP2040. The RP2040 doesn’t have a CAN peripheral, but [Kevin] wrote code for the RP2040’s PIO engine that can receive and send CAN packets. Now we can all benefit from his work by using this openly available CAN driver. This library is written in C, so it’s a good fit for the lower-level hackers among us, and in all likelihood, it wouldn’t be hard to make a MicroPython wrapper around it.

The CAN bus needs a peripheral for the messages to be handled properly, and people have been using external chips for this purpose until now. These chips, [Kevin] tells us, have lately been unavailable due to the chip shortage, making this project more valuable. The documentation is extensive and accessible, and [Kevin] details how to best use this driver. With such a tool in hand, you can now turn your Pico into a CAN tinkering toolkit, or wire up some CAN devices for use in your own projects!

[Kevin] says this code is already being used in Klipper, a framework powering 3D printers and other machines like them. As for your own purposes, you can absolutely use such a CAN tool to hack on your car – here’s a treasure trove of car hacking documentation, by the way! Thanks to the PIO engine, there seems to be no end to the RP2040’s versatility – you can even drive HDMI monitor with this PIO-based DVI code.

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The Quadrivium EnsembleBot Is A Labour Of Love

October 19, 2021 by 5 Comments

The Quadrivium EnsembleBot project is a mashup between old school musical instruments and the modern MIDI controlled world. Built by a small team over several years, these hand crafted instruments look and sound really nice.

The electronics side of things is taken care of with a pile of Arduinos and off-the-shelf modules, but that doesn’t mean the design isn’t well thought through, if a little more complicated than it could be in places. Control is taken care of with a PC sending commands over the USB to an Arduino 2560. This first Arduino is referred to as the Master Controller and has the immediate job of driving the percussive instruments as well as other instruments that are struck with simple solenoids. All these inductive loads are switched via opto-isolators to keep any noise generated by switching away from the microcontroller. A chain of four sixteen-channel GPIO expander modules are hung off the I2C bus to give even more opto-isolated outputs, as even the Arduino 2560 doesn’t quite have enough GPIO pins available. The are a number of instruments that have more complex control requirements, and these are connected to dedicated slave Arduinos via an SPI-to-CAN module. These are in various states of development, which we’ll be keeping our beady eyes on.

One of the more complex instruments is the PipeDream61 which is their second attempt to build a robotic pipe organ. This is powered by a Teensy, as they considered the Arduino to be a little too tight on resources. This organ has a temperature controller using an ATTiny85, in order to further relieve the main controller of such a burden and simplify the development a little.

Another interesting instrument is Robro, which is a robotic resophonic guitar which as they say is still work in progress despite how long they have been trying to get it to work. There’s clearly a fair bit of control complexity here, which is why it is taking so much fiddling (heh!) to get it work.

This project is by no means unique, lately we’ve covered controlling a church organ with MIDI, as well as a neat Arduino Orchestra, but the EnsembleBot is just so much more.

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