Surgery Robot Is A Real Cut Up

A robot that performs surgery is a serious thing. One bug in the control system could end with disaster. Unless of course, you’re [Michael Reeves], in which case disaster is all part of the fun. (Video, embedded below.)

Taking inspiration from The da Vinci Surgical System, [Michael] set out to build a system that was faster, while still maintaining precision. He created a belt drive gantry system, not unlike many 3D printers, laser cutters, or woodworking CNC machines. Machines like this often use stepper motors. [Michael] decided to go with [Oskar Weigl’s] ODrive and brushless motors instead. The ODrive is on open source controller which turns off the shelf brushless motors — such as those found in R/C planes or hoverboards, into precision industrial servos. Sound familiar? ODrive was an entrant in the 2016 Hackaday Prize. [Michael] was even able to do away the ubiquitous limit switch by monitoring current draw with the ODrive.

It all adds up to a serious build. But this is [Michael “laser eye” Reeves] after all. The video is meant to be entertaining, with a hidden payload of education and inspiration. The fun starts when he arms the robot with a giant kitchen knife and performs “surgery” on a pineapple. If you want to know what happens when mannequins and fake blood enter the picture, then watch the video after the break.

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Saving 4 Patients With Just 1 Ventilator

We all know that COVID-19 is stressing our health system to the limit. One of the most important machines in this battle is the ventilator. Vents are critical for patients experiencing the worst symptoms of respiratory distress from the virus. Most of the numbers predict that hospitals won’t have enough ventilators to keep up with the needs during the height of the pandemic.

Now anyone with a walkman or iPod can tell you what they do when there is one music device and two people who want to listen: Plug in a Y-connector. Wouldn’t it be great if you could do the same thing with a medical ventilator? It turns out you can – – with some important caveats.

Way back in 2006, [Greg Neyman, MD and Charlene Babcock, MD] connected four simulated patients to a single ventilator. Ventilators connect to a patient with two tubes – an inflow and an exhaust. Using common parts available in just about any hospital, the doctors installed “T-tube” splitters on the inflow and exhaust tubes. They tested this with lung simulators and found that the system worked.

There were some important considerations though. The patients must be medically paralyzed, and have similar lung capacity — you couldn’t mix an adult and a child. The tubing length for each patient needs to be the same as well. The suggestion is to place the patients in a star pattern with the ventilator at the center of the star.

[Dr. Charlene Babcock] explains the whole setup in the video after the break.

Interestingly enough, this technique went from feasibility study to reality during the Las Vegas shooting a few years ago. There were more patients than ventilators, so emergency room doctors employed the technique to keep patients alive while equipment was brought in from outside hospitals. It worked — saving lives on that dark day.

The video and technique remind us of Apollo 13 and the CO2 scrubber modifications. Whatever it takes to keep people alive. We’ve already started looking into open source ventilators, but it’s good to see that medical professionals have been working on this problem for years.

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144 7-Segment Displays Combine To Form A Mighty Clock

What do you do with 144 7-segment displays? If you’re [Frugha] you put them all together to create an epic clock. Each display has 8 individual LEDs — 7 segments, and a decimal point. Put that all together, and you’ve got 1152 individual LEDs to control. This presented a problem, as [Frugha] wanted to control the clock with a single Arduino Nano. Even charlieplexing won’t get you that many I/O lines.

The solution was a nifty little chip called the MAX7219. The ‘7219 speaks SPI and can control 64 individual LEDs. [Frugha] used 18 of them in the clock, giving him full control over all his LEDs. That’s pretty impressive, considering the last matrix 7-segment display we saw required 48 Arduinos!

Another problem is memory – 1152 “pixels” would quickly overrun the 2KB RAM in the ATmega328. This is a clock though — which means only digits 0-9 and a colon. [Frugha] picked a nice font and hand-coded lookup tables for each digit. The lookup tables are stored in ROM, saving precious RAM on the Arduino.

A clock wouldn’t be any good if it wasn’t accurate. A Tiny RTC supplies battery-backed time data. [Frugha] wrapped everything up with a neat layout on a custom PCB. Sure, you could put it in a case, but we think a clock this crazy deserves to be left open – so you can see it in all its glory.

Evolution Of A Backpack VR System

Persistence is what a hacker needs to make it to their goal. That’s exactly what it took for [Erik] to make an untethered VR backpack system.

Starting way back in the Spring of 2019, [Erik] began working on an untethered VR system. Sure, the Oculus Quest was coming out, but it wouldn’t be compatible with the game library of PC based systems. [Erik] decided he wanted the best of both worlds, so he decided to build a backpack that carries a computer powerful enough to drive the Rift S.

The initial system was to use a cut-up backpack, an HP mini PC with an external Nvidia 1060 GPU, and a basic DC-DC converter. The result? Just about nothing worked. The HP’s boot process didn’t play well with an external GPU.

[Erik] went through several iterations of this project. He switched over to a standard PC motherboard and tried a few different DC-DC converters. He settled on a device from HDPLEX rated at 200 watts continuous. The converter plugs directly into a standard 24-pin ATX motherboard power connector and isn’t much larger than the connector itself.

The old backpack with its added padding and wood frame gave way to a Zotac VR go backpack. Only the straps and frame of the Zotac are used, with [Erik’s] custom parts mounted using plywood and 3D printed parts. The outer frame is aluminum, with acrylic panels.

Power comes from 7000 mAH LiFe batteries, with each pack providing an hour of runtime. The Backpack can hold two packs though, so wiring them up in parallel should double that runtime.

We have to say this is an extremely well-documented build. [Erik] explains how he chose each component and the advantages (and pitfalls) of the choices he made. An example would be the RAM he picked. He chose DDR4 with a higher spec than he needed, just so he could undervolt the parts for longer run-times.

Not everything in VR is fun and games though – you can ditch that monitor and go with a VR desktop.

DIY PC Test Bench Puts Hardware Troubleshooting Out In The Open

If you’ve built a few PCs, you know how frustrating troubleshooting can be. Finding a faulty component inside the cramped confines of a case can be painful — whether its literal when sharp edges draw blood, or just figurative when you have to open that cramped case multiple times to make adjustments.

[Colonel Camp] decided to make life a bit easier by building this PC test bench which makes component troubleshooting much easier and can be built with old parts you probably have lying around. [Camp] was inspired by an old Linus PC Tech Tips video on the same topic. The key to the build is an old PC case. These cases are often riveted together, s a drill makes quick work of disassembling the chassis to easily get to all of the components. The motherboard pan and rear panel/card cage become the top shelf of the test bench, while the outer shell of the case becomes the base and a storage area. Two pieces of lumber support the upper shelf. The build was primed and painted with several coats of grey.

[Camp] built up his testbench with a modest motherboard, cooler and a 970 video card. He loaded up Manjaro Linux to verify everything worked. The basic hardware has already been replaced with a new system including a ridiculously huge cooler. But that’s all in a day’s work for a test bench PC.

We’ve seen some wild workbenches over the years, and this one fits right in for all your PC projects. Check out the video after the break!

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DIY Personal Assistant Robot Hears And Sees All

Who wouldn’t want a robot that can fetch them a glass of water? [Saral Tayal] didn’t just think that, he jumped right in and built his own personal assistant robot. This isn’t just some remote-controlled rover though. The robot actually listens to his voice and recognizes his face.

The body of the robot is the common “Rover 5” platform, to which [Saral] added a number of 3D printed parts. A forklift like sled gives the robot the ability to pick things up. Some of the parts are more about form than function – [Saral] loves NASA’s Spirit and Opportunity Mars rovers, so he added some simulated solar cells and other greebles.

The Logitech webcam up front is very functional — images are fed to machine learning models, while audio is processed to listen for commands. This robot can find and pick up 90 unique objects.

The robot’s brains are a Raspberry Pi. It uses TensorFlow for object recognition. Some of the models [Saral] is using are pretty large – so big that the Pi could only manage a couple of frames per second at 100% CPU utilization. A Google Coral coprocessor sped things up quite a bit, while only using about 30% of the Pi’s processor.

It takes several motors to control to robot’s tracks and sled. This is handled by two Roboclaw motor controllers which themselves are commanded by the Pi.

We’ve seen quite a few mobile robot rovers over the years, but [Saral’s] ‘bot is one of the most functional designs out there. Even better is the fact that it is completely open source. You can find the code and 3D models on his GitHub repo.

Check out a video of the personal assistant rover in action after the break.

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GPS And ADS-B Problems Cause Cancelled Flights

Something strange has been going on in the friendly skies over the last day or so. Flights are being canceled. Aircraft are grounded. Passengers are understandably upset. The core of the issue is GPS and ADS-B systems. The ADS-B system depends on GPS data to function properly, but over this weekend a problem with the quality of the GPS data has disrupted normal ADS-B features on some planes, leading to the cancellations.

What is ADS-B and Why Is It Having Trouble?

Automatic Dependent Surveillance-Broadcast (ADS-B) is a communication system used in aircraft worldwide. Planes transmit location, speed, flight number, and other information on 1090 MHz. This data is picked up by ground stations and eventually displayed on air traffic controller screens. Aircraft also receive this data from each other as part of the Traffic Collision Avoidance System (TCAS).

ADS-B isn’t a complex or encrypted signal. In fact, anyone with a cheap RTL-SDR can receive the signal. Aviation buffs know how cool it is to see a map of all the aircraft flying above your house. Plenty of hackers have worked on these systems, and we’ve covered that here on Hackaday. In the USA, the FAA will effectively require all aircraft to carry ADS-B transponders by January 1st, 2020. So as you can imagine, most aircraft already have the systems installed.

The ADS-B system in a plane needs to get position data before it can transmit. These days, that data comes from a global satellite navigation system. In the USA, that means GPS. GPS is currently having some problems though. This is where Receiver autonomous integrity monitoring (RAIM) comes in. Safety-critical GPS systems (those in planes and ships) cross-check their current position. If GPS is sending degraded or incorrect data, it is sent to the FAA who displays it on their website. The non-precision approach current outage map is showing degraded service all over the US Eastern seaboard, as well as the North. The cause of this signal degradation is currently unknown.

What Hardware is Affected?

GPS isn’t down though — you can walk outside with your cell phone to verify that. However, it is degraded. How a plane’s GPS system reacts to that depends on the software built into the GPS receiver. If the system fails, the pilots will have to rely on older systems like VOR to navigate. But ADS-B will have even more problems. An aircraft ADS-B system needs position data to operate.  If you can’t transmit your position information, air traffic controllers need to rely on old fashioned radar to determine position. All of this adds up to a safety of flight problem, which means grounding the aircraft.

Digging through canceled flight lists, one can glean which aircraft are having issues. From the early reports, it seems like Bombardier CRJ 700 and 900 have problems. Folks on are speculating that any aircraft with Rockwell Collins flight management systems are having problems.

This is not a small issue, there are hundreds or thousands of canceled flights. The FAA set up a teleconference to assess the issue. Since then, the FAA has issued a blanket waiver to all affected flights. They can fly, but only up to 28,000 feet.

This is a developing story, and we’ll be keeping an eye on it. Seeing how the industry handles major problems is always educational, and there will be much to learn in the coming days.