Dirty TRS-80 Has A Surprise Hack

[Adrian] had a TRS-80 model IV that looks like it was stored in a mulch pile. However, it seemed to have some surprises. The first hint that something was up was that the keyboard looks like a model III and there are two mystery knobs in the back.

So what’s going on? You” have to watch [Adrian’s] video below to find out. At about the six-minute mark, you’ll find that things are not at all what you might think.

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Miracle Of Science: Scotch Tape Improves Generator

We were always amused that one of the biggest scientific discoveries of the recent past — graphene — was started with pencil lead and Scotch tape. Now, researchers at the University of Alabama in Huntsville have determined that double-sided Scotch tape can improve triboelectric power generators. Triboelectric generation, of course, is nothing new. These energy harvesters take mechanical and thermal energy and turn them into tiny amounts of electricity. What’s new here is that PET plastic, aluminum, and double-sided tape can make an inexpensive generator that works well.

Keep in mind we are talking about little bits of power. In the best scenario with the device stimulated at 20 Hz, the generator peaked at 21.2 mW. That was better than some designs that only got to 7.6 mW in the same configuration.

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Hackaday Links: December 4, 2022

Well, this is embarrassing! Imagine sending a multibillion-dollar rover to an ancient lakebed on Mars only to discover after a year of poking around at the rocks that it might not actually have been a lake after all. That seems to be the impression of Jezero Crater that planetary scientists are forming after looking at the data coming back from Perseverance since it nailed the landing in what sure as heck looked like a dried-up lake, complete with a river delta system. A closer look at the sediments Perseverance has been sampling reveals a lot of the mineral olivine, which on Earth is rare near the surface because it readily reacts with water. Finding lots of olivine close below the surface of Jezero suggests that it either wasn’t all that watery once upon a time, or that what water was there was basically ice cold. The results are limited to where the rover has visited, of course, and the nice thing about having wheels is that you can go somewhere else. But if you were hoping for clear signs that Jezero was once a lake teeming with life, you might have to keep waiting.

In other space news, we have to admit to taking NASA to task a bit in the podcast a couple of weeks back for not being quite up to SpaceX’s zazzle standards with regard to instrumenting the SLS launch. Yeah, a night launch is spectacular, but not having all those internal cameras like the Falcon has just sort of left us flat. But we should have been more patient, because the images coming back from Artemis 1 are simply spectacular. We had no idea that NASA attached cameras to the solar panels of the Orion spacecraft, which act a little like selfie sticks and allow the spacecraft to be in the foreground with Earth and the Moon in the background. Seeing Earth from lunar distance again for the first time in 50 years has been a real treat, and getting our satellite in the frame at the same time is a huge bonus.

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The PalmPilot Returns, This Time In Your Browser

The PalmPilot doesn’t seem to get much retrocomputing love, but maybe it should. After all, it might not have been the very first handheld, but it was probably the most successful, and that ultimately led to the era of the smartphone. Whether you miss your old Palm applications, or never got to experience them the first time around, fear not. You can now relive them in all their glory in your browser thanks to the Internet Archive project.

There are over 500 applications and games all running in a browser-based emulator. Some of the programs don’t seem to work well, and some don’t make sense in the context of a virtual environment. But many work fine, and if you want the classic apps, just open up anything and press the home button. If you want a review of the Palm IIIe PDA from 1999, check out [VWestlife’s] video, below.

The Grafitti handwriting recognition system was state-of-the-art for the day. The key was the system could more easily recognize printing if it were mostly single strokes that always worked the same way. For example, the “A” had no crossbar and the “F” was missing the bottom horizontal line. As much as possible, you make letters with a single stroke and there was only one way to form each letter. Good times!

What was high tech back then you can now build out of spare parts. If you happen to have a Palm, you might consider giving it a much-needed backlight.

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A repair stand for bicycles with an integrated scale

DIY Repair Stand Holds Your Bike And Weighs It

If you’ve ever done maintenance or repair work on your bicycle, you’ll know that positioning a bike in your workshop isn’t trivial. You can use your bike’s kickstand, or lean it against a wall, but then you can’t work on the wheels. You can place it upside-down, but then the shifters and brake levers are hard to reach. You can hang it from the ceiling, but then you first need to install hooks and cables in hard-to-reach places. Ideally you’d want to have one of those standing clamp systems that the pros use, but their price is typically beyond a hobbyist’s budget.

Or at least, that’s how it used to be. As [Dane Kouttron] discovered, a simple wall-mounted bike clamp can be had for as little as $35 on eBay, and can easily be converted into a smart mobile repair stand. [Dane] fashioned an adjustable stand from some steel pipes he had lying around, and 3D-printed an adapter bracket to mount the bike clamp on it. This worked fine, but why stop at a simple clamp when you can expand it with, say, an integrated scale to weigh your bikes while you work on them? Continue reading “DIY Repair Stand Holds Your Bike And Weighs It”

The fully assembled RocketSwitch, with a 3D printed case on it and a USB-A connector sticking out, being held in someone's hand.

Rocket Switch – Accessibility Done With Elegance

Quite a few makers try and create devices helpful to others – today’s hack, Rocket Switch, is a lovely example of that. It’s a design by [Neil Squire] of [Makers Making Change], with a PCB that plugs onto an Adafruit Rotary Trinkey, soldering onto its exposed pads, equipping it with two headphone jacks connected to GPIOs. This is a simple design – only two headphone jacks and resistors, complete with a 3D printed case. The value is not as much in its construction, but more in what the Rocket Switch provides to its users.

This is an accessibility-enabling controller, a USB HID device which interfaces to a wide variety of headphone-jack-connectable switches. With this device, someone unable to use a computer mouse can use two tactile buttons to control their computer, either by imitating mouse clicks or by sending keypresses into accessibility software equipped a control flow for such two-switch arrangements.

Everything is open-source, and there’s an impressive amount of documentation – for 3D printing, ordering, usage, design choice explanations, and of course, a picture-peppered 15-page tutorial PDF with detailed assembly instructions for anyone who might need a Rocket Switch. Plus, [Makers Making Change] created a page where both people in need and makers with some free time can sign up to exchange these devices. It’s not the first time we see a design like this – perhaps the most famous example is Microsoft’s Xbox Adaptive Controller, something that we’ve seen a dad use to build an entertainment platform for his daughter.

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Custom-designed photoplethysmogram designed to fit in ear like an ear bud

Breathe Through Your Ears?

With all the attention given to heart rate monitoring and step counting, respiratory rate monitoring is often overlooked. Smartwatches are starting to incorporate respiratory rate monitoring more and more these days. However, current devices often simply look at breaths per minute without extracting more interesting features of the respiratory waveform which could give us more insight into our bodies than breaths per minute could alone. [Davies] and his team decided they wanted to change that by making an earbud that can measure respiratory rate. Continue reading “Breathe Through Your Ears?”