DIY USB Charging The Right Way

November 13, 2022 by 17 Comments

Since the widespread adoption of USB 1.1 in the 90s, USB has become the de facto standard for connecting most peripherals to our everyday computers. The latest revision of the technology has been USB 4, which pushes the data rate capabilities to 40 Gbit/s. This amount of throughput is mindblowing compared to the USB 1.x speeds which were three to four orders of magnitude slower in comparison. But data speeds haven’t been the only thing changing with the USB specifications. The amount of power handling they can do has increased by orders of magnitude as well, as this DIY USB charger demonstrates by delivering around 200 W to multiple devices at once.

The build comes to us from [tobychui] who not only needed USB rapid charging for his devices while on-the-go but also wanted to build the rapid charger himself and for the charger to come in a small form factor while still using silicon components instead of more modern gallium nitride solutions. The solution he came up with was to use a 24 V DC power supply coupled with two regulator modules meant for solar panel installations to deliver a staggering amount of power to several devices at once. The charger is still relatively small, and cost around $30 US dollars to make.

Part of what makes builds like this possible is the USB Power Delivery (PD) standard, which has enabled all kinds of electronics to switch to USB for their power needs rather than getting their power from dedicated, proprietary, and/or low-quality power bricks or wall warts. In fact, you can even use this technology to do things like charge lithium batteries.

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Dial-Up Internet Over WhatsApp

November 13, 2022 by 42 Comments

As we returned from Supercon 2022, we noticed many airlines offer free in-flight messaging. While the messages are handy for complaining about the seat size, it isn’t quite as exciting as access to the internet. In the air, we wondered how hard it would be to tunnel an internet connection over messaging. Funny enough, [Aleix Rodríguez Alameda] has a project that does exactly that by tunneling traffic over Whatsapp.

In [Aleix]’s case, cell carriers are pretty stingy with internet data when traveling in South America but often give unlimited WhatsApp data. So, ahead of time, two accounts are set up. A server is on one account and acts as a proxy to the broader internet and listens to messages to the server account. Then when in a restricted access setting, the client connects with a WebSocket and sends messages. The real trick for turning the WhatsApp messages into an internet connection the client can use is exposing a port from a local nodeJS web server. It connects to the WhatsApp API through a WebSocket and then acts as a proxy. Then, you set up traffic to be redirected through that port with curl or Firefox.

Packets are split to prevent you from sending too many messages, as in their testing, [Aleix]’s accounts were banned quickly. You shouldn’t expect massively fast speeds, as 300kbps was pretty typical during testing, which according to Wikipedia, is about what dial-up got with V.44 compression.

Which is around the same speed as TCP/IP tunneled over NRF23L01 radios.

Go Fly A Kite

November 13, 2022 by 17 Comments

Harvesting energy from the wind has been a commercially viable way of generating clean energy for around three decades now. Wind turbines are a reliable, proven technology but they do have some downsides, one of which is that since there’s more wind higher above the ground this usually means tall, expensive towers. There is a way around this problem, though, which is using kites to generate energy instead of a fixed turbine.

While kite generators aren’t a new idea, [Benjamin] has been working on this kite generator which has a number of improvements over existing kite generators. Like other kite generators, this one uses a tether to spin a generator which is located on the ground. But while this is similar to other kite systems, this prototype has a much simpler design and sweeps a much larger area while in flight. It also has an autopilot with multiple independent steering systems, which [Benjamin] says will allow it to stay in flight for months at a time provided there is enough wind. If there isn’t, it can land reliably, and launching it is relatively fast and simple as well.

While kites do have some obvious downsides compared to fixed turbines including a single point of failure at the tether and a large amount of cleared area to operate, they have plenty of advantages as well. They’re smaller, simpler, require no complicated yaw system, and can be easily maintained on the ground. In fact, it’s possible to build very simple kite generators out of nothing more than a hobby kite and some readily-available electrical components.

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RFID Sticker On Bike Helmet Grants Garage Access

November 13, 2022 by 11 Comments

[Glen] might describe his project of opening his garage door by way of an RFID sticker on his bike helmet as simple, but some of the interfacing he needed to do was quite complex. He walks through the project from beginning to end, and there’s plenty to learn from.

When designing an RFID access control system, one has to decide what kind of reader and what kind of tags one wishes to use. They all function more or less the same way, but there are a lot of practical considerations to take into account such as cost, range, ease of use, and security options. After a lot of research, [Glen] decided on inexpensive sticker-style tags and a compatible reader supporting credentials with an ISO14443 UID that could be suitably mounted on a building’s exterior.

The actual opening of the door was the simple part, done by interfacing to a spare remote.

Breakout boards with ready-to-use code libraries exist for some RFID readers, but that wasn’t the case for the reader [Glen] had. He ended up rolling his own code to handle communication with the reader, with a Microchip PIC18F45K50 doing all the work of reading tags and performing access control. His code is on the project’s GitHub repository, and if you also find yourself needing to interface to a reader that uses the Wiegand protocol, you might want to give it a look.

Controlling the actual garage door was the easy part. All that took was soldering two wires across the switch contacts of a spare garage door opener remote, and using a relay to close the contacts. Simple and effective. You can see it in action in the short video, embedded below the break.

Overhead door access control might be a simple concept, but it comes in all shapes and sizes when enterprising hackers start looking for solutions. We’ve seen garage doors given the DIY IoT treatment, and even seen access controlled by a car’s headlamp flashes, which actually turned out to be more secure than it sounds.

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Protect Your Property With This Fire-Breathing Billionaire

November 12, 2022 by 16 Comments

Let’s face it: if you can’t trust a fire-breathing billionaire industrialist to protect your stuff, who can you trust? (Video, embedded below.)

This one is straight out of the Really Bad Ideas™ files, and comes to us from [Marc Radinovic]. His story on this one is that he wants to protect the stuff in his new house, and felt that a face-recognition system with a flame thrower would be the best way to address that. And to somehow make it even better, said system would be built into a ridiculous portrait of everyone’s favorite plutocrat. The guts of the system are pretty much what you’d expect — a camera and a Raspberry Pi running OpenCV and a face recognition library, a butane reservoir and a solenoid valve, an arc lighter as an ignition source, and an Arduino and some completely not sketchy at all wiring to control all pieces. And LCD displays for [Elon]’s eyes, of course.

The system is trained to recognize [Marc]’s face and greets him cheerfully when he’s in view. [Non-Marc] people, however, are treated a bit less accommodatingly, up to and including a face-melting fireball. Effigies of other billionaires got the treatment; strangely, [Marc]’s face-recognition algorithm didn’t even recognize another [Mark] as a human face, which when you think about it is pretty darn funny.

So, certainly not a practical security system, and definitely not something you should build, but it’s pretty good fun anyway. It reminds us a bit of the fire-breathing duck we saw years ago.

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an RGB LED display showing expected arrival times of trams and buses sitting on a table

A Private View Of A Public Transport Sign

November 12, 2022 by 11 Comments

[Stefan Schüller] was a fan of the LED signs that display arrival information for the trams and buses in their city of Zürich. [Stefan] was having trouble finding a source to purchase the signs so, instead, decided to build one himself.

[Stefan] decided to recreate the 56×208 single color 2mm dot pitch display with an 128 x 64 P2 RGB LED screen respecting the same 2 mm pitch. The display is driven by an ESP32 DMA RGB LED matrix shield utilizing a HUB75 RGB LED matrix library, all being powered from a 5 V 4 A power supply.

In addition to driving the LED matrix display, the ESP32 polls Zürich’s public transportation API and then parses the XML for the relevant information. Since [Stefan] wanted to match the fonts as closely as possible,
he created a new font from scratch, including the bus and accessibility icons. The new font was encoded into a glyph bitmap distribution format (BDF) that was then converted to work with Adafruit’s GFX library, with [Stefan] creating a custom conversion tool, called bdf2adafruit, to do the last leg of the conversion.

Since the LED matrix had full color capability, [Stefan] decided to add a little extra flourish and color code the transportation lines with the official tram colors. All source code is available on his GitHub repository for the project, for those looking for more detail.

We’ve featured DIY builds of public transportation feeds before. With the ubiquity of low cost RGB LED displays and public APIs, hopefully we’ll see many more!

Bringing Up An Old Motherboard Is A Delicate Process

November 12, 2022 by 12 Comments

If you were around for the early days of the personal computer revolution, you’ll no doubt recall the excitement every time IBM announced a new version of its beige boxes. For a lot of us, the excitement was purely vicarious, for despite the “personal” moniker, mere mortals could rarely afford a branded IBM machine. But it was still cool to keep track of the latest releases, and dream of the days when cheap clones would make it possible to play.

[Anders Nielsen]’s recent find of an original IBM Model 5160 motherboard sort of echoes that long-ago excitement, but in a different way. This board, from a PC XT built in 1984, was in unknown condition upon arrival, so [Anders] set about a careful process to try to bring the board back to life. A quick visual inspection leaves one with a sense of both how much things have changed, and how much they’ve stayed the same. Aside from the big 40-pin DIP 8088 CPU and the BIOS ROMs, the board is almost completely populated with discrete logic chips, but at the same time, the basic footprint of a motherboard has changed very little.

The bring-up process in the video below includes checks of all the power rails for shorts, which ended up being a good call — drat those tantalums. After fixing that issue, [Anders] had a bit of trouble getting the board to POST, and eventually resorted to dumping the BIOS ROMs and inspecting the contents. One of the chips had picked up a case of the scramblies at some point, which was easy enough to fix thanks to images of the 5160 ROMs available online. We thought the trick of using a 64k ROM and just writing the BIOS image twice was pretty clever.

In the end, the board came up, although without video or keyboard — that’s for another day. Can’t find your own PC XT motherboard to play with? Then maybe you can just build one.

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