Turning A Waffle Iron Into A Reflow Station

January 10, 2021 by Dan Maloney 14 Comments

There are a ton of ways to go about building your own reflow oven. Most of these builds start with, well, an oven — usually a toaster oven — with a small but significant minority choosing to modify a hotplate. But this might be the first time we’ve seen a waffle iron turned into a reflow oven.

Of course, what [Vincent Deconinck] came up with is not an oven per se. But his “RefloWaffle” certainly gets the job done. It started with an old waffle maker and a few experiments to see just how much modification it would take to create the various thermal reflow profiles. As it turned out, the original cooking surfaces had too much thermal inertia, so [Vincent] replaced them with plain copper sheets. That made for quicker temperature transitions, plus created some space between the upper and lower heating elements for the SMD board.

As for control, [Vincent] originally used an Arduino with a relay and a thermocouple, but he eventually built a version 2.0 that used a hacked Sonoff as both controller and switch. Adding the thermocouple driver board inside the Sonoff case took a little finagling, but he managed to get everything safely tucked inside. A web interface runs on the Sonoff and controls the reflow process.

We think this is a great build, one that will no doubt see us trolling the thrift stores for cheap waffle irons to convert. We’ve seen some amazing toaster oven reflows, of course, but something about the simplicity and portability of RefloWaffle just works for us.

Careful Drilling Keeps Stadia From Listening In

January 10, 2021 by Tom Nardi 89 Comments

Google’s fledgling Stadia service leverages the Chrome ecosystem to deliver streamed PC games on mobile devices, web browsers, and TVs. While not strictly required, the company even offers a dedicated Stadia controller that connects directly to the streaming servers over its own WiFi connection to reduce overall system latency. Of course, being a Google product, the controller has a tiny microphone ~~that’s always listening in~~ for interacting with the voice assistant.

[Heikki Juva] didn’t like the privacy implications of this, but unfortunately, there appears to be no way to turn off this “feature” in software. He decided the most expedient solution would be to simply remove the microphone from the controller, but it turns out there was a problem. By researching previous teardowns, he found out that it’s nearly impossible to take the controller apart without damaging it.

So [Heikki] came up with a bold idea. Knowing roughly the position of the microphone, he would simply drill through the controller’s case to expose and ultimately remove the device. The operation was complicated by the fact that, from the teardown video he saw, he knew he’d also have to drill through the PCB to get to the microphone mounted to the opposite side. The only bright spot was that the microphone was on its own separate PCB, so physically destroying it probably wouldn’t take the whole controller out with it.

Now we don’t have to explain why drilling into a gadget powered by an internal lithium-ion battery is dangerous, and we’re not necessarily vouching for the technique [Heikki] used here. But when presented with a sealed unit like this, we admit there weren’t a lot of good options. The fact that the user should have to go to such ridiculous lengths to disable the microphone in a game controller is a perfect example of why we should try to avoid these adversarially designed devices, but that’s a discussion for another time.

In the end, with a steady and and increasingly larger bits, [Heikki] was able to put a 7 mm hole in the back of the Stadia controller that allowed him to extract the microphone in one piece. Removing the microphone seems to have had no adverse effect on the device as, surprisingly enough, it turns out that a game controller doesn’t actually need to listen to the player. Who knew?

As our devices get smarter, hidden microphones and cameras are unfortunately becoming more common. Thankfully a few manufacturers out there are taking the hint and including hardware kill switches for these intrusive features, but until that becomes the norm, hackers will have to come up with their own solutions.

Update 1/10/21: This article originally indicated that the microphone is always listening. While there is no hardware switch to disable the mic, there is a button which must be pressed to trigger the voice assistant functions. We have used strike through above to indicate the change to what was originally published.

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Lego Heist Bot Steals Keys

January 9, 2021 by Lewin Day 7 Comments

Breaking and entering is a felony offense, and one that risks the interloper receiving serious bodily harm for the trouble. Sending in a robot instead is an attractive alternative. While we doubt any actual intention to use their creation for evil, [Brick Experiment Channel] have nonetheless built a viable heist bot out of Lego.

The robot in question is actually two, that work together to execute their mission. Once lowered in the house, the scissor lift bot drives into position next to a coffee table. It then lifts its companion bot into position by extending its motor-driven linear actuators. The recovery bot then drives out onto the table, snatches a set of keys with its arm, and returns to the lift bot, before exiting the house. It’s all achieved with the use of the SBrick, a third-party Lego accessory which allows remote control of Lego motors over Bluetooth. A wireless camera also helps out with vision for the platform.

Lego really does make it easy to build quick, functional mechanisms without a whole lot of fuss. We’ve seen it employed in all sorts of ways, like this handy film scanner. Video after the break.

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South Korea Blankets Country With Free WiFi On All Public Transit

January 9, 2021 by Chris Lott 20 Comments

Wrapping up a multi-year project to provide free WiFi on all public transportation, South Korea’s Ministry of Science and Information and Communications Technology (MSIT) announced that a total of 35,006 buses had been equipped nationwide.

Previously, subscriber-based WiFi had been installed on subways and in subway stations. It was provided privately by two phone carriers and free only for their subscribers. The coverage was spotty and slow, and in 2017 the government took over and implemented a better system. With this announcement, the whole public transportation system is now covered with stable and free WiFi.

We also noticed that the government has released the details of the 220,000 WiFi access points to the public. This includes the location, IP address, and RSSI data for use by people and companies wanting to develop location-based services. What is the state of free WiFi access points in your region, and does it extend to public transportation? Do you find it reliable, or do you use your data plan when out and about?

Industrial Stack Light Keeps An Eye On Prusa Mini

January 9, 2021 by Tom Nardi 17 Comments

When most people want to keep tabs on what their 3D printer is up to while they’re out and about, they’ll install OctoPrint on a Pi and be done with it. But what if you’re just on the other side of the room? Inspired by the stack lights used on factory floors, [Jeff Glass] decided to add a similar system to his Prusa Mini so he could see what it’s up to at a glance.

It turns out you can get these lights pretty cheaply online from the usual retailers, and as [Jeff] explains in the video after the break, driving them is about as easy as it gets. Rather than being some kind of addressable device, they generally have a single common 12 or 24 volt DC wire and ground lines for each color. With a USB controlled relay board, kicking on the appropriate light is simple from your operating system of choice.

What ended up being a bit harder was finding out what the Prusa Mini was up to. The printer offers up a simple status web page, but it has a few oddball quirks that make it difficult to scrape; such as presenting a little pop-up message that you have to manually close each time you load the page. But after spending some time with the powerful Selenium library for Python, he was able to create a script that worked its way through the UI and pulled the relevant status messages. Obviously the resulting code is Prusa specific, but the general concept would work on other printers assuming you can find a reliable way to pull the device’s current status.

After coming up with a wall mounted enclosure for the electronics that doubles as a mount for the light itself, [Jeff] can now see if his printer needs attention from clear across the room. An especially nice feature when the printer is all buttoned up inside of its enclosure.

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Six Degrees Of Freedom Omnicopter With Ardupilot

January 9, 2021 by Danie Conradie 12 Comments

Modern multirotors are very maneuverable but are mostly limited to hovering in a single orientation. [Peter Hall] has gotten around this by building an omnicopter drone with six motors mounted in different orientations on a collapsed tetrahedron frame.

The shape of the frame consists of six tetrahedrons all joined together at a single point. With a motor in each frame, the drone can produce a thrust vector in any direction, to achieve six degrees of freedom. The control system is the challenging part of this project, but fortunately [Peter] is one of the Ardupilot developers. Unlike a standard multirotor, it doesn’t need to tilt to move around laterally but can keep its orientation constant. One of the limiting factors is that the motors need to stop and reverse rotation for direction changes, which takes time. At slow maneuvering speeds this isn’t a major problem, but at higher speeds rotation is noticeably less smooth.

Because the drone is symmetrical all around, keeping track of orientation is challenging for a human pilot, but it’s perfect for an autopilot system like Ardupilot. In the video after the break, [Peter] demonstrates this by flying the drone around while the autopilot rotates it randomly. The 6DoF control system is open source and a pull request is live to integrate it into the official version of Ardupilot. The obvious application for this sort of drone is for inspection in and around structures.

This omnicopter is an entry into the Lynchpin drone competition by the celebrity [Terrence Howard]. We’re not quite following his claims regarding the scientific significance of this shape, which he named the “Lynchpin”, but it works for drones. Continue reading “Six Degrees Of Freedom Omnicopter With Ardupilot” →

AVR Microcontroller Doubles Up As A Switching Regulator

January 9, 2021 by Anool Mahidharia 26 Comments

[SM6VFZ] designed, built and tested a switched-mode DC-DC boost regulator using the core independent peripherals (CIP) of an ATtiny214 micro-controller as a proof of concept, and it looks pretty promising!

A Buck, Boost, or Buck-Boost switching regulator topology usually consists of a diode, a switching element (MOSFET) and an energy storage device (inductor/capacitor) in the power path, and a controller that can measure the output voltage, control the switching element and add safety features such as current limiting and temperature shutdown. A search for switching regulators or controllers throws up thousands of parts, and it’s possible to select one specifically well suited for any desired application. Even so, the ability to use the micro-controller itself as the regulator can have several use cases. Such an implementation allows for a software configurable switch-mode regulator and easy topology changes (boost, buck, fly back etc.).

The “Getting Started with Core Independent Peripherals on AVR®” application note is a good place to get an overview of how the CIP functionality works. Configurable Custom Logic (CCL) is among one of the powerful CIP peripherals. Think of CCL as a rudimentary CPLD — a programmable logic peripheral, which can be connected to a wide range of internal and external inputs such as device pins, events, or other internal peripherals. The CCL can serve as “glue logic” between the device peripherals and external devices. The CCL peripheral offers two LookUp Tables (LUT). Each LUT consists of three inputs, a truth table, a synchronizer, a filter, and an edge detector. Each LUT can generate an output as a user programmable logic expression with three inputs and any device that have CCL peripherals will have a minimum of two LUTs available.

This napkinCAD sketch shows how [SM6VFZ] implemented the boost regulator in the ATtiny214. The AND gate is formed using one of the CCL LUT’s. The first “timer 1” on the left, connected to one input of the AND gate, is free running and set at 33 kHz. The analog comparator compares the boosted output voltage against an internally generated reference voltage derived from the DAC. The output of the comparator then “gates” timer 1 signal to trigger the second “timer 2” — which is a mono-shot timer set to max out at 15 us. This makes sure there is enough time left for the inductor to completely release its energy before the next cycle starts. You can check out the code that [SM6VFZ] used to built this prototype, and his generous amounts of commenting makes it easy to figure out how it works.

Based on this design, the prototype that he built delivers 12 V at about 200 mA with an 85% efficiency, which compares pretty well against regular switching regulators. Keep in mind that this is more of a proof-of-concept (that actually works), and there is a lot of scope for improvement in terms of noise, efficiency and other parameters, so everyone’s comments are welcome.

In an earlier blog post, we looked at how ATmegas with Programmable Logic came about with this feature that is usually found in PIC micro-controllers, thanks to Microchip’s acquisition of Atmel a few years back. But we haven’t seen any practical example of the CCL peripheral in an Atmel chip up until now.