Day: April 9, 2020

What Does A Dependable Open Source Ventilator Look Like?

April 9, 2020 by 61 Comments

Ventilators are key in the treating the most dire cases of coronavirus. The exponential growth of infections, and the number of patients in respiratory distress, has outpaced the number of available ventilators. In times of crisis, everyone looks for ways they can help, and one of the ways the hardware community has responded is in work toward a ventilator design that can be rapidly manufactured to meet the need.

The difficult truth is that the complexity of ventilator features needed to treat the sickest patients makes a bootstrapped design incredibly difficult, and I believe impossible to achieve in quantity on this timeline. Still, a well-engineered and clinically approved open source ventilator might deliver many benefits beyond the current crisis. Let’s take a look at some of the efforts we’ve been seeing recently and what it would take to pull together a complete design.

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Decentralized Privacy-Preserving Proximity Tracing

April 9, 2020 by 6 Comments

As we continue through the pandemic, whether we are on lockdown or still at work, there is a chance for all of us that we could still pick up the virus from a stray contact. Mapping these infections and tracing those in proximity to patients can present a major problem to infection control authorities, and there have been a variety of proposals for smartphone apps designed to track users’ contacts via the Bluetooth identities their phones encounter. This is a particular concern to privacy advocates, because there is a chance that some governments could use this as an excuse to bring in intrusive personal surveillance by this means. A group of academics from institutions across Europe have come together with a proposal for a decentralised proximity tracing system that allows identification of infection risk without compromising the privacy of those using it.

Where a privacy-intrusive system might use a back-end database tracking all users and recording their locations and interactions, this one uses anonymised tokens stored at the local level rather than at the central server. When a user is infected this is entered at app level rather than at server level, and the centralised part of the system merely distributes the anonymised tokens to the clients. The computation of whether contact has been made with an infected person is thus made on the client, meaning that the operator has no opportunity to collect surveillance data. After the pandemic has passed the system will evaporate as people stop using it, rather than remaining in place harvesting details from installed apps. They are certainly not the first academics to wrestle with this thorny issue, but they seem to have ventured further into the mechanics of it all.

As with all new systems, it’s probably good to subject it to significant scrutiny before deploying it live. Have a read. What do you think?

We are all watching our authorities as they race to respond to the pandemic in an effective manner, and we hope that should they opt for an app that it does an effective job and they resist the temptation to make it too intrusive. Our best course of action meanwhile as the general public is to fully observe all advised public health measures such as self-isolation or the wearing of appropriate personal protective equipment.

Adding RGB To A CRT

April 9, 2020 by 30 Comments

There was a time when all TVs came with only an antenna socket on their backs, and bringing any form of video input to them meant dicing with live-chassis power supplies. Then sets with switch-mode supplies made delving into a CRT TV much safer, and we could bodge in composite video and even RGB sockets by tapping into their circuitry. For Europeans the arrival of the SCART socket gave us ready-made connectivity, but in the rest of the world there was still a need to break out the soldering iron for an RGB input. [Jacques Gagnon] is in Canada, and has treated us to a bit of old-school TV input hacking as he put an RGB socket on his JVC CRT set.

Earlier hacks had inventive incursions into discrete analogue circuitry, but on later sets such as this one the trick was to take advantage of the on-screen-display features. The signal processing chip would usually have an RGB input with a blanking input to turn of the picture during the OSD chip’s output. These could be readily hijacked to provide an RGB input, and this is the course taken here. We see a VGA socket on the rear panel going to a resistor network on a piece of protoboard stuck in a vacant space on the PCB, from which a set of lines then go to the signal processing chip. The result is a CRT gaming monitor for retro consoles, of the highest quality.

For those of us who cut our teeth on CRT TVs it’s always good to see a bit of TV hacking. It’s a mod we’ve seen before, too.