Close-up of the mod installed into the HDMI switch, tapping the IR receiver

Interfacing A Cheap HDMI Switch With Home Assistant

June 7, 2024 by Arya Voronova 38 Comments

You know the feeling of having just created a perfect setup for your hacker lab? Sometimes, there’s just this missing piece in the puzzle that requires you to do a small hack, and those are the most tempting. [maxime borges] has such a perfect setup that involves a HDMI 4:2 switch, and he brings us a write-up on integrating that HDMI switch into Home Assistant through emulating an infrared receiver’s signals.

The HDMI switch is equipped with an infrared sensor as the only means of controlling it, so naturally, that was the path chosen for interfacing the ESP32 put inside the switch. Fortunately, Home Assistant provides the means to both receive and output IR signals, so after capturing all the codes produced by the IR remote, parsing their meaning, then turning them into a Home Assistant configuration, [maxime] got HDMI input switching to happen from the comfort of his phone.

We get the Home Assistant config snippets right there in the blog post — if you’ve been looking for a HDMI switch for your hacker lair, now you have one model to look out for in particular. Of course, you could roll your own HDMI switch, and if you’re looking for references, we’ve covered a good few hacks doing that as part of building a KVM.

CH32V003 Makes For Dirt Cheap RISC-V Computer

May 31, 2024 by Tom Nardi 36 Comments

These days, when most folks think of a computer they imagine a machine with multiple CPUs, several gigabytes of RAM, and a few terabytes of non-volatile storage for good measure. With such modern expectations, it can be difficult to see something like a microcontroller as little more than a toy. But if said MCU has a keyboard, is hooked up to a display, and lets you run basic productivity and development software, doesn’t that qualify it as a computer? It certainly would have in the 1980s.

With that in mind, [Olimex] has teased the RVPC, which they’re calling the “world lowest cost Open Source Hardware All-in-one educational RISC-V computer” (say that three times fast). The tiny board features the SOIC-8 variant of the CH32V003 and…well, not a whole lot else. You’ve got a handful of passives, a buzzer, an LED, and the connectors for a PS/2 keyboard, a power supply, and a VGA display. The idea is to offer this as a beginner’s soldering kit in the future, so most most of the components are through-hole.

On the software side, the post references things like the ch32v003fun development stack, and the PicoRVD programmer as examples of open source tools that can get your CH32V computer up and running. There’s even a selection of retro-style games out there that would be playable on the platform. But what [Olimex] really has their eye on is a port of VMON, a RISC-V monitor program.

When paired with the 320×200 VGA text mode that they figure the hardware is capable of, you’ve got yourself the makings of an educational tool that would be great for learning assembly and playing around with bare metal programming.

It might not have the timeless style of the Voja4, but at least you can fit it in a normal sized pocket.

Thanks to [PPJ] for the tip.

CH32V003 Provides Ultra Cheap Speech Recognition

May 30, 2024 by Jenny List 6 Comments

Speech recognition was once the stuff of science fiction, but it’s now possible with relatively modest hardware. Just how modest, you ask? How about a 10 cent microcontroller?

[Brian Smith] has achieved a very basic form of speech recognition on a CH32V003 RISC-V microcontroller. It may only recognize spoken digits, but that it does so at all on such a modest platform is impressive in itself.

For training purposes it enlists the help of a desktop Linux computer, however the recognition process is purely in the ten cent chip. He goes into much detail about how it achieves this on a system without floating point arithmetic, as well as the other shortcomings of such a limited platform.

We’ve become used to thinking of super-cheap chips as of limited use, but the truth is they’re surprisingly more capable than expected. We’re seeing them starting to appear as subsidiary processors on some badges, so it will be interesting to see them proliferate in more projects now their availability problems have eased. Go on – for ten cents, what do you have to lose?

Upgrading A Cheap LX-2BUPS UPS Board To Fix Fatal Flaws

May 6, 2024 by Maya Posch 28 Comments

Cheap uninterruptable power supply (UPS) boards that take Li-ion cells of some description seem to have cropped up everywhere the past years. Finding use in applications such as keeping single-board computers ticking along in the case of a power failure, they would seem to be a panacea. Unfortunately most of these boards come with a series of fatal flaws, such as those that [MisterHW] found in an LX-2BUPS board obtained from AliExpress. Worst of all was the deep discharge of the Li-ion cells to below 2 V, which took some ingenuity and hard work to fix this and other problems.

The patched up XR2981 boost IC with MCP809 reset IC installed. (Credit: [MisterHW])

This particular board is rated for 5V at 3A, featuring the all too common TP4056 as charging IC and the XYSemi XR2981 boost converter. Since there is no off-switch or other protections on the board, the XR2981 will happily keep operating until around 2.6V, at a rather astoundingly high idle power consumption. Because of this the fixes mostly concentrated on optimizing the XR2981, by using better resistor values (R7, R8, R9), as well as adding a 3.15V MCP809 reset IC, to reduce idle power usage of the boost converter and disable it below a safe cell voltage.

The final coup de grâce was the eviction of the red LED (D6) and replacing it with the blue LED from D2, to stop the former from draining the cell as well. With these changes in place, no-load power usage dropped from nearly 900 µA to just over 200 µA, while preventing deep discharge. Although this board now has a second life, it does raise the question of what the point of these cheap UPS boards is if you have to spend money and time on reworking them before they’re somewhat acceptable. What is your go-to solution for these boards?

Hackaday Podcast Episode 269: 3D Printed Flexure Whegs, El Cheapo Bullet Time, And A DIY Cell Phone Sniffer

May 3, 2024 by Kristina Panos 1 Comment

This week, it was Kristina’s turn in the hot seat with Editor-in-Chief Elliot Williams. First up in the news — the results are in for the 2024 Home Sweet Home Automation contest! First and second place went to some really gnarly, well-documented hacks, and third went to the cutest pill-dispensing robot you’ll probably see before you hit the retirement home. Which was your favorite? Let us know in the comments.

A collection of multimeter probe extenders from Radio Shack. — Kristina’s lil’ wallet of extender probes, courtesy of Radio Shack.

Then it’s on to What’s That Sound. Kristina failed once again, but you will probably fare differently. Can you get it? Can you figure it out? Can you guess what’s making that sound? If you can, and your number comes up, you get a special Hackaday Podcast t-shirt.

Then it’s on to the hacks, beginning with a DIY cell phone sniffer and a pen that changed the world. Then we talk bullet time on a budget, the beautiful marriage of 3D printing and LEGO, and, oh yes, flexure whegs. Finally, we get the lowdown on extender probes, and posit why it’s hard to set up time zones on the Moon, relatively speaking.

Check out the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Download and savor at your leisure.

Continue reading “Hackaday Podcast Episode 269: 3D Printed Flexure Whegs, El Cheapo Bullet Time, And A DIY Cell Phone Sniffer” →

Cheap Musical Tesla Coil Put Through Its Paces

May 1, 2024 by Lewin Day 4 Comments

Once upon a time, musical Tesla coils were something you primarily saw at high-voltage hobby meets. They’ve become more popular in recent years, and now you can even buy cheap examples online. [mircemk] decided to buy one and gave it a whirl.

The device comes with a power supply capable of delivering 2 amps at 48 V. It’s a solid-state design, relying on SMD MOSFETs to generate high-voltage, high-frequency output that makes the sparks we all know and love. The pancake coil is key to the design, and is made using a trace on the PCB — a neat technique compared to making one with a laborious winding operation.

The coil can be used to simply generate sparks, or it can be modulated musically. In this mode of operation, it’s intended to be driven by square wave audio for simplicity’s sake. As seen in [mircemk]’s video, the sound quality is pretty decent for a cheap device, and the Super Mario theme is readily recognizable. As a guide, he also demonstrates how to drive the device using an Arduino set up for square wave audio output.

If you prefer to build your own singing Tesla coil, you can go that route instead. Or, you could buy one of these and hack it, and drop us a line with what you come up with! Similar devices are all over the ‘net. Continue reading “Cheap Musical Tesla Coil Put Through Its Paces” →

A render of the USB Blaster, showing all the major parts

The Cheapest USB Blaster Ever, Thanks To CH552

April 30, 2024 by Arya Voronova 8 Comments

Here’s a CH552G-based USB Blaster project from [nickchen] in case you needed more CH552G in your life, which you absolutely do. It gives you the expected IDC-10 header ready for JTAG, AS, and PS modes. What’s cool, it fits into the plastic shell of a typical USB Blaster, too!

The PCB is flexible enough, and has all the features you’d expect – a fully-featured side-mounted IDC-10 header, two LEDs, a button for CH552 programming mode, and even a UART header inside the case. There’s an option to add level shifter buffers, too – but you don’t have to populate them if you don’t want to do that for whatever reason! The Hackaday.io page outlines all the features you are getting, though you might have to ask your browser to translate from Chinese.

Sadly, there’s no firmware or PCB sources – just schematics, .hex, BOM, and Gerber .zip, so you can’t fix firmware bugs, or add the missing USB-C pulldowns. Nevertheless, it’s a cool project and having the PCB for it is lovely, because you never know when you might want to poke at a FPGA on a short notice. Which is to say, it’s yet another CH552 PCB you ought to put in your PCB fab’s shopping cart! This is not the only CH552G-based programming dongle that we’ve covered – here’s a recent Arduino programmer that does debugWire, and here’s like a dozen more different CH552G boards, programmers and otherwise.