Grbl Ported to the ESP32

If you’re building a CNC or laser, there’s an excellent chance you’ll be using Grbl to get moving. It’s also a pretty safe bet you’d end up running it on some variation of the Arduino sitting in a motor controller breakout board. It’s cheap, easy to setup and use, and effectively the “industry” standard for DIY machines so there’s no shortage of information out there. What’s not to love?

Well, quite a few things in fact. As [bdring] explains, Grbl pushes the capability of the Arduino to the very limit; making it something of a dead-end for future development. Plus the Arduino needs to be plugged into the host computer via USB to function, a rather quaint idea to many in 2018. These were just some of the reasons he decided to port Grbl to the ESP32 board.

Price wise the Arduino and ESP32 are around the same, but the ESP does have the advantage of being much more powerful than the 8-bit Italian Stallion. Its got way more flash and RAM as well, and perhaps most importantly, includes Wi-Fi and Bluetooth out of the box. It still needs to be plugged into a board to hold the motor drivers like the Arduino, but beyond that [bdring] opines the ESP32 is about as close to the perfect Grbl platform as you can get.

[bdring] reports that porting the code over to the ESP32 wasn’t terrible, but it wasn’t exactly a walk in the park either. The bulk of the code went by without too much trouble, but when it came to the parts that needed precise timing things got tricky. The ESP32 makes use of a Real Time Operating System (RTOS) that’s not too happy about giving up control of the hardware. Turning off the RTOS was an option, but that would nuke Bluetooth and Wi-Fi so obviously not an ideal solution. Eventually he figured out how to get interrupts more or less playing nicely with the RTOS, but mentions there’s still some more work to be done before he’s ready to release the firmware to the public.

If you’ve been browsing Hackaday for a while you may remember [bdring]. He’s got a real knack for making things move, and has created a number of fantastic little CNC machines recently which have definitely caught our eye.

[Thanks to Jon and Craig for the tip.]

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LoRa With The ESP32

If you are interested in deploying LoRa — the low power long-range wireless technology — you might enjoy [Rui Santos’] project and video about using the ESP32 with the Arduino IDE to implement LoRa. You can see the video below. He uses the RFM95 transceivers with a breakout board, so even if you want to use a different processor, you’ll still find a lot of good information.

In fact, the video is just background on LoRa that doesn’t change regardless of the host computer you are using. Once you have all the parts, getting it to work is fairly simple. There’s a LoRa library by [Sandeep Mistry] that knows how to do most of the work.

Although the project uses an RFM95, it can also work with similar modules such as the RFM96W or RFM98W. There are also ESP32 modules that have compatible transceivers onboard.

This is one of those projects that probably isn’t useful all by itself, but it can really help you get over that hump you always experience when you start using something new. Once you have the demo set up, it should be easy to mutate it into what you really need.

We’ve been talking about LoRa a lot lately. We’ve even seen it commanding drones.

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ESP32 Boards With Displays: An Overview

The ESP8266 has become practically the 555 chip of WiFi connected microcontrollers. Traditionally, you’d buy one on a little breakout board with some pins and a few connectors, and then wire up anything else you need. The ESP8266’s big brother, the ESP32, hasn’t quite taken over from the ESP8266, but it has a lot more power and many more options. [Andreas] has a new video that shows seven new ESP32 boards that have integral displays. These boards can simplify a lot of applications where you need both WiFi and a user interface.

Of the boards examined, six of them have OLED displays, but one has an E-paper display. To summarize results, [Andreas] summarized his findings on these seven along with others in an online spreadsheet.

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Fast LED Matrix Graphics For The ESP32

Many of you will have experimented with driving displays from your microcontroller projects, and for most people that will mean pretty simple status information for which you’d use standard libraries and not care much about their performance. If however any of you have had the need for quickly-updating graphics such as video or game content, you may have found that simpler software solutions aren’t fast enough. If you are an ESP32 user then, [Louis Beaudoin] may have some good news for you, because he has ported the SmartMatrix library to that platform. We’ve seen his demo in action, and the results as can be seen in the video below the break are certainly impressive.

In case you are wondering what the SmartMatrix library is, it’s an LED matrix library for the Teensy. [Louis]’s port can be found on GitHub, and as he was explaining to us over a beer at our Cambridge bring-a-hack, it takes extensive advantage of the ESP32’s DMA capabilities. Making microcontrollers talk with any sort of speed to a display is evidently a hot topic at the moment, [Radomir Dopieralski]’s talk at our Dublin Unconference a few weeks ago addressed the same topic.

We have to admit a soft spot for LED panels here at Hackaday, and given the ESP32’s power we look forward to writing up the expected projects that will come our way using this library.

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Build Your Own Supercomputer with ESP32s

If the computer you have isn’t particularly fast, there’s a well-documented way to get more out of it. You just need more of the same computer, and you can run your tasks on them all at the same time. Building computer clusters is an effective way of decreasing the time it takes for computers to solve certain problems, even if the computers themselves aren’t top-of-the-line hardware. Of course, with cheap enough hardware, people will build clusters out of just about anything, including the ESP32.

For this project, [Wei Lin] admits that this isn’t really a serious attempt at building speedy hardware, but rather an interesting exercise in creating a cluster as a sort of learning experience. ESP32 boards can be found for around $10 so building an experimental cluster with these is even more feasible than using the Raspberry Pi. [Wei Lin] goes into a great amount of detail on his GitHub page about all of his goals with the project, most of which involve exploring the functionality of the new cluster and its underpinnings.

While this might seem like little more than a thought experiment, it does have the advantage of being a great solution for problems that involve gathering data from points that are physically very far from one another. If you’ve ever been interested in parallel computing or computing clusters, this is a great project to check out. If you have more Raspberry Pis on hand than ESP32s and still want to build a cluster, check out this project that used a mere 750 of them for one.

 

Emulating OBD-II on the ESP32

It used to be that you could pop the hood and with nothing more than flat head screwdriver, some baling wire, and tongue held at the optimal angle, you could fix anything that ailed your car. But today, for better or for worse, the average automobile is a rolling computer that runs on gasoline and hope (if it even still has a gasoline engine, that is). DIY repairs and maintenance on a modern car is still possible of course, but the home mechanic’s toolbox has needed to evolve with the times. If you want to do anything more advanced than changing a tire, you’ll really want to have the gear to interface with the vehicle’s computer via the OBD-II port.

But for some, even that isn’t enough. [limiter121] recently wrote in to tell us of an interesting project which doesn’t read the OBD-II port in a vehicle, but actually emulates one. Like so many others this hack was born out of necessity, as a way to test an OBD-II project without having to sit out in the driveway all day. It allows you to create fictitious speed and engine RPM values for the OBD-II device or software under test to read, complete with a slick web interface to control the “car”.

So what makes it tick? Surprisingly little, actually. At the most basic level, an ESP32-WROOM-32 is connected up to a SN65HVD230 CAN transceiver chip. You’ll also need a 3.3V power supply, as well as a USB to serial adapter to do the initial programming on the ESP32. From there it’s just a matter of compiling and flashing the code [limiter121] has made available in the GitHub repo.

If you’re wondering if such products don’t already exist on the commercial market, they do. But like so many other niche projects, the price is a bit hard to swallow for the home hacker. Compared to the nearly $300 USD list price of commercial offerings such as the Freematics OBD-II Emulator, building one of these ESP32 based emulators should only cost you around $20.

Unless you’re developing an OBD-II reader, you probably don’t have much use for an OBD-II emulator. But this project could still be useful for anyone who wants to learn more about OBD from the comfort of their couch.

Software Defined Television on an ESP32

Composite video from a single-board computer? Big deal — every generation of Raspberry Pi has had some way of getting composite signals out and onto the retro monitor of your choice. But composite video from an ESP32? That’s a thing now too.

There are some limitations, of course, not least of which is finding a monitor that can accept a composite input, but since [bitluni]’s hack uses zero additional components, we can overlook those. It really is as simple as hooking the monitor up to pin 25 and ground because, like his recent ESP32 AM radio station, the magic is entirely in software. For video, [bitluni] again uses his I²S tweaks to push a lot of data into the DAC really fast, reproducing the sync and image signals in the 0-1 volt range of the PAL composite standard. His code also supports the NTSC standard, but alas because of frequency limitations in the hardware it’s monochrome only for both standards, at least for now. He’s also got a neat trick to improve performance by running the video signal generation and the 3D-rendering on separate cores in the ESP32. Check out the results in the video below.

It looks like the ESP32 is getting to be one of those “Is there anything it can’t do?” systems. Aside from radio and video, we’ve seen audio playback, vector graphics, and even a Basic interpreter easter egg.

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