Start Your Day With The Mountain That Rises

December 4, 2019 by Tom Nardi 3 Comments

Like many of us, [Zach Archer] enjoys the comfort of his darkened room so much that he has trouble getting up and facing the day. To make things a little easier for himself, he decided to put together a custom alarm clock that would fill his mornings with the glorious glow of LEDs; and since he finds the mountains an inspirational sight he decided to wrap the whole thing up in a 3D printed enclosure that resembles snow capped peaks.

But even Bob Ross himself couldn’t have imagined a snowy mountain range that featured an integrated e-ink screen. The big 4.2″ panel is connected to a custom designed PCB by [romkey], which was graciously donated for this project. An ESP32 runs the show, providing a convenient web interface to control not only the clock, but various aspects of the mountain’s internal LEDs such as fade in time and total duration.

[Zach] says he originally printed the mountains in PLA, but the heat generated by the LEDs eventually started to cause things to warp. Switching over to translucent PETG not only solved the heat problem, but made for a very effective LED diffuser. Rather than complex animation patterns, he’s found that smoothly transitioning between different shades of blue and green seems to work best for him in the mornings.

This isn’t the first time we’ve seen somebody use LEDs to get them out of bed in the morning, but we do appreciate the aesthetic that [Zach] has achieved here between the design of the mountains and the impressive artwork on the e-ink display. Then again, we’re also quite partial to this version that looks like a warp core, so our tastes do run the gamut.

Zombies Ate Your Neighbors? Tell Everyone Through LoRa!

December 4, 2019 by Sven Gregori 24 Comments

As popular as the post-apocalyptic Zombie genre is, there is a quite unrealistic component to most of the stories. Well, apart from the whole “the undead roaming the Earth” thing. But where are the nerds, and where is all the apocalypse-proof, solar-powered tech? Or is it exactly this lack of tech in those stories that serves as incentive to build it in the first place? Well, maybe it doesn’t have to be the end of the world to seek for ways to cope with a collapse of our modern communication infrastructure either. Just think of natural disasters — an earthquake or hurricane causing a long-term power outage for example. The folks at [sudomesh] tackle exactly this concern with their fully open source, off-grid, solar-powered, LoRa mesh network, Disaster Radio.

The network itself is built from single nodes comprising of a battery-backed solar panel, a LoRa module, and either the ESP8266 or ESP32 for WiFi connectivity. The idea is to connect to the network with your mobile phone through WiFi, therefore eliminating any need for additional components to actually use the network, and have the nodes communicate with each other via LoRa. Admittedly, LoRa may not be your best choice for high data rates, but it is a good choice for long-range communication when cellular networks aren’t an option. And while you can built it all by yourself with everything available on [sudomesh]’s GitHub page, a TTGO ESP32 LoRa module will do as well.

If the idea itself sounds familiar, we did indeed cover similar projects like HELPER and Skrypt earlier this year, showing that LoRa really seems to be a popular go-to for off-grid communication. But well, whether we really care about modern communication and helping each other out when all hell breaks loose instead of just primevally defending our own lives is of course another question.

A Printed Case For Your ESP Environmental Sensors

November 28, 2019 by Tom Nardi 16 Comments

We’ve said it before but it’s worth repeating: rolling your own hardware solution is ridiculously easy these days. If you want to make a network attached environmental sensor, you wire a DHT11 up to an ESP8266 and you’re done. Time to move onto the software. In fact, it can take longer to come up with some kind of suitable enclosure for your hardware project than it does to assemble the thing.

Which is why [Pixel Hawk] has come up with this elegant 3D printed enclosure for the ESP8266 and ESP32. It’s designed to hold the microcontroller in the bottom compartment, while the environmental sensor (either the DHT11 or DHT22) is mounted to the top so it’s exposed to the outside. The case snap fits together so you don’t have to worry about gluing it, and there’s even an opening so you can keep the USB cable plugged in.

In the notes for the design, he mentions that in testing it was determined that the heat of the ESP itself can skew the temperature readings. So he recommends putting the microcontroller to sleep whenever possible, and keeping reads short so the enclosure doesn’t have time to heat up. He’s also created an alternate version of the case with more openings which should help combat this issue if you need to keep the chip awake.

If you’re looking for a complete solution, [Pixel Hawk] has included the source code he personally used to get his ESP32 sensor talking to Blynk, but you certainly don’t have to go that route if you don’t want to. There’s no shortage of existing projects out there that will help you get started with whole-house environmental monitoring. Our very own [Elliot Williams] happens to be partial to MQTT when he wants to get all his gadgets to play nice.

The ESP32, Laid Bare

November 17, 2019 by Jenny List 31 Comments

Most readers will be familiar with the ESP32, Espressif’s dual-core processor with integrated WiFi and Bluetooth. Few of us though will have explored all of its features, including its built-in encryption facilities and secure booting capability. With these, a developer can protect and secure their code, and keep their devices secure.

That sense of security may now be illusory though, thanks to [LimitedResults] who has developed a series of attacks on the chip that compromise its crypto core, secure boot, and flash encryption. This enables both the chance of arbitrary code execution and firmware extraction on locked-down ESP32 devices.

To achieve all this he used a glitching technique on the device’s power supply, inserting a carefully timed glitch in the rail to coincide with a particular instruction being executed. For those of us who are not experts in this technique, he provides a basic primer with a description of his home-made glitcher made using a CMOS switch chip.

It appears that there is no solution to this attack short of new silicon, however, it should be borne in mind that it’s something that depends upon a specialist hacker with a well-equipped bench, and is thus only likely to be a significant headache to manufacturers. But it undermines a key feature of a major line of microcontrollers, and as such it remains a significant piece of work.

A Self-Expanding PWM Driver

November 15, 2019 by Bryan Cockfield 8 Comments

For smaller microcontrollers, having enough outputs for the job is sometimes a challenge. A common solution is to do some sort of multiplexing with the available outputs or perhaps something more advanced such as Charlieplexing, but another good option is to use a specialized driver board. What’s even better is if you can daisy chain driver boards to get even more outputs.

[Eric] has been working on a 16 channel LED project but first wanted to build a driver board with 8 channels. Before building a full 16 channel version he realized that he could take the same 8 channel board, make a mirror image of it, and attach it underneath the first board with headers in order to double the number of channels available. Without having to build a separate 16-channel board, this shortcut saved [Eric] some time and a great deal of effort.

This is a great example of working smarter, not harder. Each of the 8 or 16 channels has full PWM support as well to support PWM dimming, and a similar board could be built for motor control as well. It’s a good illustration of how good design can end up working for you as well. And if you need even more outputs, Charlieplexing is one way to get them.

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Improbably Cheap Pocket Welder Gets An ESP32 Makeover

November 4, 2019 by Dan Maloney 25 Comments

If you move in certain shady circles, you may have noticed the crop of improbably cheap “pocket welders” popping up on the market these days. They’re all variations on a theme, most with wildly optimistic specs minimal accessories of the lowest possible quality. But their tiny size and matching price make them irresistible to the would-be welder, as well as attractive to hardware hackers.

With a 220-V outlet in the garage waiting to be filled and well-knowing the risks, [Mr. RC-Cam] purchased one of these diminutive welding machines. Its shortcomings were immediately apparent, and a complete rework of the welder was undertaken. After addressing safety issues like the lack of a ground connection, [Mr. RC-Cam] added a color-matched 3D-printed hood to house a fancy new LCD touchscreen display. Backing that up is an ESP32 with Bluetooth, which supports remote control via a key fob. He also added a current sense board that uses the welder’s current shunt to measure welding current. Expediently calibrated using a waffle iron and a milli-ohmmeter, the sensor showed that the 200A max advertised for the welder was more like 100A. He tried adding some big electrolytics to fix the current issues, but no dice. With a decent stinger and ground clamp, the modified welder is good enough for his needs, and much was learned in the process. We call that a hacking win.

As an aside, [This Old Tony] recently did a review on a similar welder if you want more details on the internals. We also covered the conversion of a buzz-box to a TIG welder recently, should that be more your style.

Continue reading “Improbably Cheap Pocket Welder Gets An ESP32 Makeover” →

ESP32 Makes Great MPPT Controller In Low-Cost Solar Installation

November 4, 2019 by Dan Maloney 34 Comments

Solar power projects have become, in general, a matter of selecting components like panels and batteries, hooking them together with industry-standard connectors, and sitting back to watch the free electricity flow. As such, solar projects have become a bit boring, so it’s not often we see one that attracts our attention the way this dirt-cheap open-source solar project does.

The backstory on [Tim O’Brien]’s DIY off-grid PV system starts with his desire to charge his eWheel, which amounts to a battery-powered standing unicycle. They look like a fun option for getting around an urban environment if you have the requisite degree of coordination, which we clearly lack. But charging something like that or an eBike is a great use case for solar, especially since [Tim] happened upon a 450W PV panel on the cheap. Sadly, the panel was a commercial unit, and compatible off-the-shelf MPPT, or maximum power-point tracking, controllers are expensive.

His solution was to build his own controller using a cheap DC-DC converter that just so happens to have serial remote control. An ESP32 monitors the panel voltage and controls the buck converter to run whatever he wants. When he’s not charging his eWheel, the system runs his laptop and router. As a bonus, the ESP32 talks to IoT services like Adafruit.io and Thingspeak, allowing him to track MPPT data without shipping it off to parts unknown.

While we appreciate a DIY MPPT controller and like [Tim]’s build, we feel like the documentation needs a bit of fleshing out. With solar installations, the devil is in the details, and not addressing seemingly mundane issues like cable routing and connector installation can lead to disaster.