HPi95LX Puts Linux In Your Palm

November 29, 2021 by Chris Lott 30 Comments

A few decades ago, palmtop computers were mostly based on MS-DOS, and while many users tried to mimic the UNIX experience, the results were mixed. Fast forward to the present and business-card-sized Linux computers modules abound. Canadian tinkerer [Rune Kyndal] decided to make his own Linux palmtop by sacrificing an old HP-95LX and replacing the guts with a Raspberry Pi Zero and a color LCD screen. We’re impressed with the rich set of features he has crammed into the limited volume of the case:

Raspberry Pi Zero W
Color LCD, 4.3 inch, 800×480 w/Backlight
Capacitive touch screen (not connected yet)
Stereo speakers + microphone
Ethernet 10/100
USB 2.0, 2 each
RS-232, DE-9 connector
microSD card
HDMI
IR dataport
Webcam (TBD)
LiPo Battery w/Charger

One problem that any palmtop faces is how to make a usable keyboard, and HP had one of the better designs. The keys are the same famous style as used in HP calculators. And while no human with normal hands could touch-type on it, the keyboard’s layout and tactile feel was well-suited to “thumb typing”. [Rune] made a good decision by keeping the original keyboard.

While fully functional, this is more of a proof of concept than a polished project. [Rune] primarily used bits and pieces that he had laying around. [Rune] says if he did it again, he would replace all the hot-glued accessory parts with a custom PCB, which is probably good advice. If you want to make your own, check out the project comments for some suggestions.

Do You Really Need To Dry Filament?

November 29, 2021 by Dave Rowntree 46 Comments

There’s a lot of opinions and theories around the storing and drying of 3D printing materials. Some people are absolutely convinced you must bake filament if it been stored outside an airtight bag, even for a few days. Some others have ‘never had a problem.’ So it’s about time someone in the know has done some testing to try to pin down the answer to the question we’re all asking; How bad is wet filament really?

[Thomas Sanladerer] setup a simple experiment, using samples of three common types of filament, specifically PLA, PET-G and ASA. He stored the samples in three environments, on his desk, outside in the garden, and finally submerged in water for a full week. What followed was a whole lot of printing, but they all did print.

Different filaments will absorb water at different rates, depending upon their chemical composition and the environment, nylon being apparently particularly fond of a good soaking. It would seem that the most obvious print defect that occurs with increased water absorption is that of stringing, and other than being annoying and reducing surface quality somewhat, it’s not all that serious in the grand scheme of things. It was interesting to note that water absorption doesn’t seem to affect the strength of the final part.
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A scrolling name badge that uses LED matrices.

Scrolling Name Badge Is Sure To Break The Ice

November 29, 2021 by Kristina Panos 2 Comments

Most makerspaces and hackerspaces have one night per week or month where the ‘space is open to the public in order to entice new people into joining up. Whereas most members just write their name in Sharpie on a piece of masking tape, [Madison] wanted to do something extra. And what better way to get people interested in your ‘space than by wearing something useful that came out of it?

The badge runs on an ATtiny45 and uses three 8×8 ultra-bright LED matrices for scrolling [Madison]’s name. It’s powered by a tiny LiPo battery that is boosted to 5 V. This build really shows off a number of skills, especially design. We love the look of this badge, from the pink silkscreen to the the typography. One of the hardest things about design is finding fonts that work well together, and we think [Madison] chose wisely. Be sure to check it out in action after the break.

Custom name badges are a great way to start conversations no matter where you go. Here’s one that uses EL wire and LEDs that light up in sequence for an animated effect.

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Spatial AI And CV Hack Chat

November 29, 2021 by Dan Maloney No comments

Join us on Wednesday, December 1 at noon Pacific for the Spatial AI and CV Hack Chat with Erik Kokalj!

A lot of what we take for granted these days existed only in the realm of science fiction not all that long ago. And perhaps nowhere is this more true than in the field of machine vision. The little bounding box that pops up around everyone’s face when you go to take a picture with your cell phone is a perfect example; it seems so trivial now, but just think about what’s involved in putting that little yellow box on the screen, and how it would not have been plausible just 20 years ago.

Perhaps even more exciting than the development of computer vision systems is their accessibility to anyone, as well as their move into the third dimension. No longer confined to flat images, spatial AI and CV systems seek to extract information from the position of objects relative to others in the scene. It’s a huge leap forward in making machines see like we see and make decisions based on that information.

To help us along the road to incorporating spatial AI into our projects, Erik Kokalj will stop by the Hack Chat. Erik does technical documentation and support at Luxonis, a company working on the edge of spatial AI and computer vision. Join us as we explore the depths of spatial AI.

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, December 1st at 12:00 PM Pacific time. If time zones have you tied up, we have a handy time zone converter.

Detect Starlink Satellites Passing By

November 29, 2021 by Bryan Cockfield 16 Comments

The Starlink beta has semi-officially ended, but it seems as though the global chip shortage is still limiting how many satellites are flying around the world for broadband internet access for those that might not be served by traditional ISPs. Not every location around the world has coverage even if you can get signed up, so to check that status the hard way you can always build a special antenna that tracks the Starlink beacons as they pass overhead.

[Derek] is using this project to show of some of his software-defined radio skills, so this will require an SDR that can receive in the 1600 MHz range. It also requires a power injector to power the satellite receiver, but these are common enough since they are used to power TV antennas. The signals coming from the Starlink satellites have a very high signal-to-noise ratio so [Derek] didn’t even need a dish to focus the signals. This also helped because the antenna he is using was able to see a much wider area as a result. Once everything was set up and the computer was monitoring the correct location in the spectrum, he was able to see very clearly how often a satellite passed him by.

Of course, [Derek] lives in an area with excellent coverage so this might be a little more difficult for those in rural areas, but possibly not for long as the goal of Starlink is to bring broadband to people who otherwise wouldn’t have access to it. There is some issue with how much these satellites might interfere with other astronomical activities though, so take that with a grain of salt.

Thanks to [Spritle] for the tip!

Laptop keyboard with strange characters on the keys

But Think Of The (World Wide) Users!

November 29, 2021 by Al Williams 47 Comments

History is full of stories about technology that makes sense to the designer but doesn’t really fit the needs of the users. Take cake mixes. In 1929, a man named Duff realized that he could capitalize on surplus flour and molasses and created a cake mix. You simply added water to the dry mix and baked it to create a delicious cake. After World War II General Mills and Pillsbury also wanted to sell more flour so they started making cakes. But sales leveled out. A psychologist who was a pioneer in focus groups named Dichter had the answer: bakers didn’t feel like they were contributing to the creation of the cake. To get more emotional investment, the cake mixes would need to have real eggs added in. Actually, Duff had noticed the same thing in his 1933 patent.

It is easy to imagine a bunch of food… scientists? Engineers? Designers?… whatever a person inventing flour mixes in the 1930s was called… sitting around thinking that making a mix that only requires water is a great thing. But the bakers didn’t like it. How often do we fail to account for users?

From Cake Mix to Tech

Apple has made a business of this. Most of us don’t mind things like arcane commands and control key combinations, but the wider pool of global computer users don’t like those things. As the world continues to virtually shrink, we often find our users are people from different lands and cultures who speak different languages. It is, after all, the world wide web. This requires us to think even harder about our users and their particular likes, dislikes, and customs.

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Wireless LEDs Aren’t Really Magic

November 29, 2021 by Al Williams 18 Comments

[Atomic14] bought some wireless LEDs that receive power from a base station. They were very neatly packaged, but — we like it — he took one apart and made his own versions. They may not look as polished, but they work and they are undeniably cool.

The LEDs work by receiving power from an induction coil. Once you have power, lighting up an LED is no big deal. Reverse engineering found the transmitter sends 217 kHz into a 2.2 mH inductor. A capacitor resonates the coil and drives the attached LED.

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