New Part Day: The Fifty Cent USB Chip

October 3, 2018 by Brian Benchoff 144 Comments

If you want to plug a USB cable into your next project, you’ve got a problem. USB is not UART, and UART is what every microcontroller serial port wants. To add USB to your microcontroller project, you’ll need to add a support chip, probably from FTDI, although there are a multitude of almost-FTDI clones available from the other parts of the Internet. These parts are slightly expensive, and they require some support circuitry. What you really need is a simple device that requires minimal external components, takes in serial from your microcontroller and spits out USB, and costs no more than a dollar. Bonus points if it’s hand-solderable.

The CH330 is apparently the answer to this problem (That’s a TaoBao link, this is probably going to be the best link going forward). It’s a dead simple chip with eight pins. Two are the data lines on a USB cable, and two are TX and RX for your microcontroller. The other pins are just power, ground, and an RTS line. Best of all, it only costs about fifty cents. You’ve never heard about it, because a few hours after this post is published, it will be the most information you’re going to get on this chip in the English-speaking world.

As far as we can tell, the CH330 is the smallest in a line of USB to UART converters from WCH, although the part isn’t even on the company’s website. The first reference to the phrase ‘CH330’ in reference to a USB chip appeared about a month ago, at the beginning of September. There’s a GitHub for someone who is apparently using this chip in a Pine64 board, but that’s about it. There’s no more information.

Right now, the only documentation for this chip is a single Chinese-language datasheet with an example schematic showing this chip connected to a MAX232 as a USB to RS232 converter. This is it. You’re looking at all the information that exists on this chip in the English-speaking version of the Internet.

The idea of a cheap, small chip that easily turns USB into UART would be great for thousands of projects. An FTDI chip will work, yes, but if you’re making thousands of a thing you might want to go with the fifty cent part over the two dollar part. That said, we’re in untested waters with this part, and you can’t even find it on AliExpress.

Let us know if you’ve gotten your hands on one of these devices. This has the potential to be really useful in a lot of projects and products, and we’re eager to see what the community comes up with. Thanks to [acabx] for sending this one in on the tip line.

Bitcoin’s Double Spending Flaw Was Hush-Hush During Rollout

October 2, 2018 by Pedro Umbelino 15 Comments

For a little while it was possible to spend Bitcoin twice. Think of it like a coin on a string, you put it into the vending machine to get a delicious snack, but if you pull the string quickly enough you could spend it again on some soda too. Except this coin is worth something like eighty-grand.

On September 20, the full details of the latest fix for the Bitcoin Core were published. This information came two days after the fix was actually released. Two vulnerabilities were involved; a Denial of Service vulnerability and a critical inflation vulnerability, both covered in CVE-2018-17144. These were originally reported to several developers working on Bitcoin Core, as well as projects supporting other cryptocurrencies, including ABC and Unlimited.

Let’s take a look at how this worked, and how the network was patched (while being kept quiet) to close up this vulnerability.

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Tiny WiFi-Enabled ARM MCU For Tiny Projects

October 2, 2018 by Maya Posch 62 Comments

Ever since the ESP8266 WiFi-enabled microcontroller came on the scene, it seemed like suddenly everyone came up with WiFi-enabled projects. But the ESP8266 is not the only game in town! Reader [PuceBaboon] notified us of a new product released by Seeed Studios: the imaginatively called Air602 WiFi Development Board.

The core of this board is the tiny WinnerMicro W600 MCU, which integrates a 32-bit ARM Cortex M3 CPU, along with dual UARTs, I2C, SPI and I2S interfaces, as well as a real-time clock (RTC). Add to this hardware crypto, seven I/O pins (five broken out on the development board) and you have a very capable WiFi-enabled MCU which can be programmed using the usual ARM development tools (e.g. Keil) using the provided SDK.

The W600 module can be bought by itself, in all its diminutive 12 mm x 10 mm glory, for a mere $1.90 as of time of writing – without antenna – as noted in [PuceBaboon]’s thoughts on this MCU and the development board.

High Detail 3D Printing With An Airbrush Nozzle

October 1, 2018 by Tom Nardi 38 Comments

On a fused deposition modeling (FDM) 3D printer, the nozzle size dictates how small a detail you can print. Put simply, you can’t print features smaller than your nozzle for the same reason you’d have trouble signing a check with a paint roller. If the detail is smaller than the diameter of your tool, you’re just going to obliterate it. Those who’ve been around the block a few times with their desktop 3D printer may have seen this come up in practice when their slicer refused to print lines which were thinner than the installed nozzle (0.4mm on the vast majority of printers).

Smaller nozzles exist for those looking to improve their printer’s detail on small objects, but [René Jurack] wasn’t happy with just putting a finer nozzle on a stock E3D-style hotend. In his opinion it’s still a hotend and arrangement intended for 0.4mm printing, and doesn’t quite fully realize the potential of a smaller diameter nozzle. After some experimentation, he thinks he’s found the solution by using airbrush nozzles.

As [René] sees it, the hotend is too close to the subject being printed when using nozzles finer than 0.4mm. Since you’re working on tiny objects, the radiant heat from the body of the hotend being only a few millimeters away is enough to deform what you’re working on. But using the long and tapered airbrush nozzle, the hotend is kept at a greater distance from the print. In addition, it gives more room for the part cooling fan to hit the print with cool air, which is another critical aspect of high-detail FDM printing.

Of course, you can’t just stick an airbrush nozzle on your E3D and call it a day. As you might expect, they are tiny. So [René] designed an adapter that will let you take widely available airbrush nozzles and thread them into an M6 threaded hotend. He’s now selling the adapters, and judging by the pictures he posted, we have to say he might be onto something.

If you’re more about brute strength than finesse, you might be interested in outfitting your E3D with a ruby nozzle instead.

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Remember When Blockbuster Video Tried Burning Game Cartridges On Demand?

October 1, 2018 by Drew Littrell 32 Comments

By the onset of the 1990s one thing was clear, the future was digital. Analog format sales for music were down, CD sales were up; and it was evident, at least in the US, that people were bringing more computing devices into their homes. At the beginning of the decade, roughly 1 in 3 American households had a Nintendo Entertainment System in them, according to this Good Morning America segment.

With all those consoles out there, every shopping season became a contest of “who could wait in line the longest” to pickup the newest titles. This left last minute shoppers resorting to taking a rain check or return home empty handed. Things didn’t have to be this way. The digital world had emerged and physical media just needed to catch up. It would take an unlikely alliance of two disparate companies for others to open their minds.

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Inductance In PCB Layout: The Good, The Bad, And The Fugly

September 28, 2018 by Bil Herd 39 Comments

When current flows through a conductor it becomes an inductor, when there is an inductor there is an electromagnetic field (EM). This can cause a variety of issues during PCB layout if you don’t plan properly, and sometimes we get burned even when we think we have planned for unwanted inductance and the effects that come with them.

When doing high speed logic we need to be able to deliver sudden changes in current to the devices if we want to have proper switching times and logic levels. Unfortunately inductance is usually not a friend in these circumstances as it resists those sudden changes in current. If the high speed devices are driving capacitive loads, which themselves are resisting changes in voltage, even more instantaneous current is needed.

Simply put, inductors resist a change of current, and can act as a low pass filter when in series with the signal or power supply flow. Inductors do this by storing energy in the flux surrounding the conductor. Alternatively capacitors resist a change in voltage (again by storing energy) and can act as a high pass filter when in series with the signal. This makes them a valuable tool in the fight against unwanted inductance in power supply distribution.

In the video below, and the remainder of this article, I’m going to dive into the concept of inductance and how it affects our design choices when laying out circuit boards.

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Laser Noob: Getting Started With The K40 Laser

September 27, 2018 by Adam Fabio 77 Comments

Why spend thousands on a laser cutter/engraver when you can spend as little as $350 shipped to your door? Sure it’s not as nice as those fancy domestic machines, but the plucky K40 is the little laser that can. Just head on down to Al’s Laser Emporium and pick one up. Yes, it sounds like a used car dealership ad, but how far is it from the truth? Read on to find out!

Laser cutting and engraving machines have been around for decades. Much like 3D printers, they were originally impossibly expensive for someone working at home. The closest you could get to a hobbyist laser was Epilog laser, which would still cost somewhere between $10,000 and $20,000 for a small laser system. A few companies made a go with the Epilog and did quite well – notably Adafruit used to offer laptop laser engraving services.

Over the last decade or so things have changed. China got involved, and suddenly there were cheap lasers on the market. Currently, there are several low-cost laser models available in various power levels. The most popular is the smallest – a 40-watt model, dubbed the K40. There are numerous manufacturers and there have been many versions over the years. They all look about the same though: A blue sheet metal box with the laser tube mounted along the back. The cutting compartment is on the left and the electronics are on the right. Earlier versions came with Moshidraw software and a parallel interface.