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

The Cheapest USB Blaster Ever, Thanks To CH552

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.

The board shown in real life, top and bottom, showing the pinout and alternate functions silkscreened.

A CH552G Devboard In Case You Missed It

We might just never get tired of covering cool small cheap MCUs, and CH552G sure fits this description. Just so you know, here’s a Hackaday.io project you should check out – a CH552G devboard that’s as simple as it sufficient, in case you needed a tangible reminder that this chip exists, has a lively community, and is very much an option for your projects.

The devboard design by [Dylan Turner] is so straightforward, it’s almost inspiring – a square of PCB with the chip in the center and plenty of empty space for your mods. Everything is open-source with KiCad sources stored on GitHub. The most lovely aspect of this board, no doubt, is having the pin mapping written on the bottom, with all the alternate pin functions – you won’t have to constantly glance at the datasheet while wiring this one up. Plus, of course, there’s the microUSB port for programming, and the programming mode button that a few CH552 projects tend to lack.

It’s simple, it’s self-documenting, it’s breadboardable, and it’s definitely worth putting into the shopping cart at your PCB fab of choice. Oh, and there are bringup instructions on GitHub, in case you need them. Whether you want to prototype the cheapest macropad or keyboard ever, or perhaps a reflow hotplate, the CH552 delivers. If these CH552 projects aren’t enough to light your fire, here are a dozen more.

A “Full” Keyboard For $5*

Sure, we’ve all seen PCB business cards at this point, but what about giving away a full-blown keyboard at meetups and such? That’s just how cost-effective the idawgz32 keyboard is. How on Earth can it cost so little? [sporewoh] used the CH552 microcontroller, which comes in around a dollar and only needs a couple of capacitors to get it up and running. The firmware is FAK.

As [sporewoh] writes in this blog post about the keyboard, they did some analysis and realized that most of the cost of their previous tiny board came from the switches. In addition to switching up the switches, [sporewoh] performed a few tricks to get the cost down, like making the key spacing 9 mm x 9 mm so that the overall board is less than 100 mm x 100 mm (which triggers a deal at a certain board house).

Unfortunately, the switches turned out not to be so good. They had greater travel and required more actuation force than the ones [sporewoh] was used to with previous board. The switches were also scratchy, which was solved with a little Krytox. But ultimately, they are pretty unreliable, so the next revision will use Panasonic EVQP0N02Bs.

If this seems familiar, you may be recalling this $3 macro pad which uses the same chip, or maybe the fact that we’ve covered the CH552 in detail.

*Thanks to the current CAD to USD exchange rate.

A Compact SMD Reflow Hotplate Powered By USB-PD

When it comes to home-lab reflow work, there are a lot of ways to get the job done. The easiest thing to do perhaps is to slap a PID controller on an old toaster oven and call it a day. But if your bench space is limited, you might want to put this compact reflow hotplate to work for you.

There are a lot of nice features in [Toby Chui]’s build, not least of which is the heating element. Many DIY reflow hotplates use a PCB heater, where long, thin traces in the board are used as resistive heating elements. This seems like a great idea, but as [Toby] explains in the project video below, even high-temperature FR4 substrate isn’t rated for the kinds of temperatures needed for some reflow profiles. His search for alternatives led him to metal ceramic heaters (MCH), which are commonly found in medical and laboratory applications. The MCH he chose was rated for 20 VDC at 50 watts — perfect for powering with USB-PD.

The heater sits above the main PCB on a Kapton-wrapped MDF frame with a thermistor to close the loop. While it’s not the biggest work surface we’ve seen, it’s a good size for small projects. The microcontroller is a CH552, which we’ve talked about before; aside from that and the IP2721 PD trigger chip needed to get the full 60 watts out of the USB-PD supply, there’s not much else on the main board.

This looks like a nice design, and [Toby] has made all the design files available if you’d like to give it a crack. Of course, you might want to freshen up on USB-PD before diving in, in which case we recommend [Arya]’s USB-PD primer.

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Cheap LCD Uses USB Serial

Browsing the Asian marketplaces online is always an experience. Sometimes, you see things at ridiculously low prices. Other times, you see things and wonder who is buying them and why — a shrimp pillow? But sometimes, you see something that probably could have a more useful purpose than the proposed use case.

That’s the case with the glut of “smart displays” you can find at very low prices. Ostensibly, these are being sold as system monitors. A business-card-sized LCD hooks up via USB and shows your CPU speed, temperature, and so on. Of course, this requires sketchy Windows software. I don’t run Windows, and if I did, I wouldn’t be keen to put some strange service on just so I could see tiny displays of my system information. But a 3.5-inch IPS LCD screen for $15 or less probably has some other uses. But how to drive it? Turns out, it is easier than you think and the hardware looks reasonably hackable, too.

Like a lot of this cheap stuff, these screens are sold under a variety of names, and apparently, there are some subtle differences. Two of the main makers of these screens are Turing and XuanFang, although you rarely see those names in the online listings. As you might expect, though, someone has reverse-engineered the protocol, and there is Python software that will replace the stock Windows software the devices use. Even better, there is an example of using the library for your own purposes.

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Macro Pad Cheap Enough To Give Away

Supercon 2022 showed that hackers are starting to come together again in Maker Faires, conventions, and festivals. [Toby Chui] plans to be one of those hackers and wants something to give to fellow attendees. Thus, the $3 Macro Pad was born.

We’ve seen our fair share of macro pads, so a simple four-key pad isn’t exactly novel. However, the focus on size and cost makes it stand out. The pad is the size of a business card, making it easy to give away. For a microcontroller, [Toby] used a CH552G, which is cheap and compatible with the Arduino IDE. Although, with 10 GPIO, a matrix layout could have supported a full-sized number pad, the diodes required would have added to the cost significantly. A cheap PCB and 3d-printed base make up the device’s bulk.

[Toby] provides a handy tool for assigning keys from your browser without coding. However, the source code is on GitHub if you want to develop a more complicated scheme. This isn’t the first time we’ve featured the CH552 chip, and it likely won’t be the last.

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A Hackaday.io page screenshot, showing all the numerous CH552 projects from [Stefan].

All The USB You Can Do With A CH552

Recently, you might have noticed a flurry of CH552 projects on Hackaday.io – all of them with professionally taken photos of neatly assembled PCBs, typically with a USB connector or two. You might also have noticed that they’re all built by one person, [Stefan “wagiminator” Wagner], who is a prolific hacker – his Hackaday.io page lists over a hundred projects, most of them proudly marked “Completed”. Today, with all these CH552 mentions in the Hackaday.io’s “Newest” category, we’ve decided to take a peek.

The CH552 is an 8-bit MCU with a USB peripheral, with a CH554 sibling that supports USB host, and [Stefan] seriously puts this microcontroller to the test. There’s a nRF24L01+ transceiver turned USB dongle, a rotary encoder peripheral with a 3D-printed case and knob, a mouse wiggler, an interface for our beloved I2C OLED displays, a general-purpose CH55x devboard, and a flurry of AVR programmers – regular AVRISP, an ISP+UPDI programmer, and a UPDI programmer with HV support. Plus, if USB host is your interest, there’s a CH554 USB host development board specifically. Every single one of these is open-source, with PCBs designed in EasyEDA, the firmware already written (!) and available on GitHub, and a lovingly crafted documentation page for each.

[Stefan]’s seriously put the CH552 to the test, and given that all of these projects got firmware, having these projects as examples is a serious incentive for more hackers to try these chips out, especially considering that the CH552 and CH554 go for about 50 cents a piece at websites like LCSC, and mostly in friendly packages. We did cover these two chips back in 2018, together with a programming guide, and we’ve seen things like badges built with its help, but having all these devices to follow is a step up in availability – plus, it’s undeniable that all the widgets built are quite useful by themselves!