Overview of the Gwyscope SPM controller.

Low-Cost DSP For Scanning Probe Microscopy

January 31, 2024 by Maya Posch 3 Comments

A scanning probe microscope comes in a wide variety of flavors, they all produce a set of data points containing the measurements at each location. Usually these data points form a regular 2D grid, but it can be more beneficial to change the density of measurements at certain locations, or even the height, which creates a much more complex probing path and subsequent (XYZ) data set.

Yet this should not deter anyone, as [Miroslav Valtr] and colleagues demonstrate in a July 2023 article in Hardware X where they use a Red Pitaya SBC along with custom Eurocard-format PCBs to create a low-cost-ish (<1,500 USD) open hardware Digital Signal Processor (DSP) they call Gwyscope.

How the Gwyscope controller fits into an example of a scanning probe microscope setup. (Credit: Miroslav Valtr et al., 2023)

The Red Pitaya itself is used as a convenient hybrid FPGA-based module with on-board signal processing hardware, with its Xilinx Zynq ARM-FPGA chip providing both an FPGA section to implement the feedback loop module in Verilog, as well as the means to run a Linux instance with the C-based software that connects via Ethernet to a remote workstation. This communication is based around the GwyFile library, which is part of the Gwyddion project. The scanning paths are generated using libgwyscan (see this presentation for an introduction).

The resulting scan data is saved as an XYZ data file, which can be read with the Gwyddion visualization and analysis program. Although far from a quick & easy afternoon project for the casual hobbyist, it could be a boon for universities and laboratories.

Thanks to [Nicolae Irimia] for the tip.

Android-Powered Rigol Scopes Go Wireless

January 18, 2024 by Al Williams 9 Comments

The Rigol DHO800 and DHO900 series use Android underneath, and as you might expect, this makes them easier to hack. A case in point: [VoltLog] demonstrates that you can add WiFi to the scope using a cheap USB WiFi adapter. This might seem like a no-brainer on the surface, but because the software doesn’t know about WiFi, there are a few minor hoops to jump through.

The first issue is that you need a WiFi adapter the built-in OS already knows how to handle. The community has identified at least one RTL chipset that works and it happens to be in the TP-Link TL-WN725N. These are old 2.4 GHz only units, so they are widely available for $10 or less.

But even with the correct hardware, the scope doesn’t have any menus to configure the WiFi interface. To solve that, you need to temporarily use a USB hub and a USB keyboard. Once you have everything plugged in, you can use the Super + N keyboard shortcut to open up the Android notification bar, which is normally hidden. Once you’ve setup the network connection, you won’t need the keyboard anymore.

Or maybe not — it turns out the keyboard does allow you to change a few other things. For example, [VoltLog] used it to increase the screen brightness more than the default maximum setting.

The only other issue appears to be that the scope shows it is disconnected even when connected to WiFi. That doesn’t seem to impact operation, though. Of course, you could use a WiFi to Ethernet bridge or even an old router, but now you have a cable, a box, and another power cord to deal with. This solution is neat and clean. You bet we’ve already ordered a TP-Link adapter!

WiFi scopes are nothing new. We suspect Rigol didn’t want to worry about interference and regulatory acceptance, but who knows? Besides, it is fun to add WiFi to wired devices.

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$50 10Gbps Mesh Network Uses USB4

January 16, 2024 by Al Williams 30 Comments

You want to build a cluster of computers, but you need a high-speed network fabric that can connect anything to anything. Big bucks, right? [Fang-Pen] developed a 10 Gbps full-mesh network using USB4 that cost him under $50. The first part of the post is about selecting a low-power mini PC, but if you skip down to the “Networking” section, you’ll find the details on the cluster.

The machines selected have two USB4 ports. In theory, you can transfer 40 Gbps on these ports. In reality, the cluster only hit 11 Gbps, but that’s still well above common Ethernet speeds. [Fang-Pen] has yet to determine why he isn’t getting even faster speeds.

Since Linux is Linux, there is a module for networking over Thunderbolt, so the rest is basically set up. There are, of course, some limitations. First, it is only fully connected because the cluster has three computers. More computers would need more USB4 ports or more hardware.

In addition, the standard says you can only count on full speed with cables 0.8 meters or shorter. However, that’s the 40 Gbps number. We wondered if a 2 m cable, rated at 20 Gbps, would have still managed 11 Gbps in this setup. A 10GBASE-T network, on the other hand, should allow 100-meter cables. But for a cluster of computers, do you really care?

We’d be interested to see this idea extended to more nodes. High-speed fabric can be useful in networked disk servers, parallel computing, and probably some other scenarios. We’ve seen 10G Ethernet on the Pi, although the PCI bus limited it to about 3.6 Gbps. For reference, we saw another three computer networks with 10GBASE-T done for about $130 with similar limitations.

Reverse-Engineering The ESP32’s WiFi Binary Blob With A Faraday Cage

January 15, 2024 by Maya Posch 37 Comments

The Faraday cage constructed by Jasper Devreker.

As part of a team reverse-engineering the binary blob driver for the ESP32’s WiFi feature at Ghent University, [Jasper Devreker] saw himself faced with the need to better isolate the network packets coming from the ESP32-under-test. This is a tough call in today’s WiFi and 2.4 GHz flooded airwaves. To eliminate all this noise, [Jasper] had to build a Faraday cage, but ideally without racking up a massive invoice and/or relying on second-hand parts scavenged from eBay.

We previously reported on this reverse-engineering project, which has since seen an update. Although progress has been made, filtering out just the packets they were interested in was a big challenge. The solution was a Faraday cage, but on a tight budget.

Rather than relying on exotic power filters, [Jasper] put a battery inside a Faraday cage he constructed out of wood and conductive fabric. To get Ethernet data in and out, a fiber link was used inside a copper tube. Initial testing was done using a Raspberry Pi running usbip and a WiFi dongle. The Faraday cage provided enough attenuation that the dongle couldn’t pick up any external WiFi signals in listening mode.

The total cost of this build came down to a hair over €291, which makes it feasible for a lot of RF experiments by hobbyists and others. We wish [Jasper] and the rest of the team a lot of luck in figuring out the remaining secrets of Espressif’s binary WiFi blob using this new tool.

802.11ah Wi-Fi HaLOW: The 1 Kilometer WiFi Standard

January 7, 2024 by Maya Posch 31 Comments

The 802.11ah WiFi (HaLow) standard is fairly new, having only been introduced in 2017. It’s supposed to fall somewhere between standard WiFi used in domiciles and offices and the longer range but low-bitrate LoRaWAN, ZigBee, and others, with bandwidth measured in megabits per second. In a recent video, [Ben Jeffery] looks at the 802.11ah chipsets available today and some products integrating these.

The primary vendors selling these chipsets are TaiXin Semiconductor (TXW8301), Morse Micro (MM6108), and Newracom (NRC7394), with a range of manufacturers selling modules integrating these. Among the products using these, [Ben] found an Ethernet range extender kit (pictured) that takes 12V input as power, along with Ethernet. Running some distance tests in a quarry showed that 300 meters was no problem getting a strong signal, though adding some trees between the two transceivers did attenuate the signal somewhat.

Another interesting product [Ben] tested is what is essentially an 802.11ah-based WiFi extender, using an 802.11ah link between the server node – with an Ethernet socket – and a client that features a standard 2.4 GHz 802.11n that most WiFi-enabled devices can connect to. Using this, he was able to provide a solid ~10 Mbps link to a cabin near the main house (~10 meters) through two outside walls. What makes 802.11ah so interesting is that it is directly compatible with standard Ethernet and WiFi protocols and uses the 900 MHz spectrum, for which a wide range of alternative antennae exist that can conceivably extend the range even more.

(Thanks to [Keith Olson] for the tip)

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CH32 RISC-V MCUs Get Official Arduino Support

January 4, 2024 by Tom Nardi 29 Comments

Like many of you, we’ve been keeping a close eye on the CH32 family of RISC-V microcontrollers from WCH Electronics. You can get the CH32V003, featuring 2 kB RAM and 16 kB of flash for under fifteen cents, and the higher-end models include impressive features like onboard Ethernet. But while the hardware is definitely interesting, the software side of things has been a little rocky compared to what we’ve come to expect from modern MCUs.

Things should start looking up a bit though with the release of an Arduino core for the CH32 direct from WCH themselves. It’s been tested on Windows, Linux, and Mac, and supports the CH32V00x, CH32V10x, CH32V20x, CH32V30x, and CH32X035 chips. Getting it installed is as easy as adding the URL to the Arduino IDE’s Boards Manager interface, though as the video below shows, running it on Linux does require an extra step or two.

So far, we’ve seen several projects, like this temperature sensor or this holiday gizmo that use [cnlohr]’s open-source toolchain. But there’s no question that plenty of hobbyists out there feel more comfortable in the Arduino environment, and if those folks are now able to pick up a CH32 and do something cool, that means more people jumping on board, more libraries developed, more demo code written…you get the idea.

Just like the ESP8266’s popularity exploded when it was added to the Arduino IDE, we’ve got high hopes for the CH32 family in the coming months.

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Parachute Drops Are Still A Viable Solution For Data Recovery From High Altitude Missions

December 19, 2023 by Lewin Day 12 Comments

Once upon a time, when the earliest spy satellites were developed, there wasn’t an easy way to send high-quality image data over the air. The satellites would capture images on film and dump out cartridges back to earth with parachutes that would be recovered by military planes.

It all sounds so archaic, so Rube Goldberg, so 1957. And yet, it’s still a viable method for recovering big globs of data from high altitude missions today. Really, you ask? Oh, yes indeed—why, NASA’s gotten back into the habit just recently!

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