Reverse Engineering A Very Cheap Fitness Band

July 8, 2021 by Lewin Day 10 Comments

With the rise of big-name smartwatches in the marketplace, there are also a smattering of lower-end offerings. The M6 fitness band is one of them, and [Raphael] set about hacking the cheap device with a custom firmware of his own creation.

The M6 band, which sells for around $6, appears to trade on name similarity to the more expensive (~$50) Xiaomi Mi Smart Band 6 fitness tracker. Upon disassembly, [Raphael] found that the system-on-chip running the show is a Telink TLSR8232. It’s paired with a 160×80 display, a small LiPo battery for power, and a vibration motor and what appears to be a fake heart rate sensor.

[Raphael] wanted to flash the SOC with a new firmware, and learned a lot from code for a similar part created by [atc1441]. It took some time to figure out how to program the chip using the somewhat oddball SWire interface, but [Raphael] persevered and eventually got things going after much research and experimentation.

From there, it was yet further work to figure out how to read the capacitive button input as well as how to drive the screen, but [Raphael] succeeded in the end. The final result was whipping up a firmware that allowed him to read Bluetooth Low Energy soil moisture sensors he has installed in his plants at home.

It’s not [Raphael], aka [rbaron]’s first bite at the cherry; we’ve featured his efforts in hacking similar fitness bands before! Video after the break.

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A Plastic Injection Machine You Can Use At Home

July 7, 2021 by Lewin Day 25 Comments

3D printing is all well and good if you want one of something, but if you want lots of plastic parts that are all largely identical, you should consider injection molding. You can pay someone to do this for you, or, in true hacker fashion, you can build an entire injection molding setup in your own garage, as [Action BOX] did.

The build relies on a pair of beefy 3hp motors to drive the screw-based injection system. These are responsible for feeding plastic pellets from a hopper and then melting them and filling the injection reservoir, before then forcing the hot plastic into the mold. Further stepper motors handle clamping the mold and then releasing it and ejecting the finished part. A Raspberry Pi handles the operation of the machine, and is configured with a custom Python program that is capable of proper cycle operation. At its peak, the machine can produce up to 4 parts per minute.

It’s an impressive piece of industrial-type hardware. If you want to produce a lot of plastic things in your own facility, a machine like this is very much the way to go. It’s not the first machine of its type we’ve seen, either! Video after the break. Continue reading “A Plastic Injection Machine You Can Use At Home” →

How To Make A Collapsible Container Without Breaking Down

July 5, 2021 by Kristina Panos 5 Comments

How hard could it be to make a collapsible silicone container? Turns out, it’s really, really hard — collapsible containers have rigid guidelines. Just ask [Eric Strebel], who failed dozens of times before finally getting it right (video, embedded below).

[Eric] started with an SLA-printed two-part mold and a silicone formulation with a Shore durometer of A 40 — this is the measure of hardness for silicone, polymers, and elastomers in the sense that the piece will resist indentation. The first twenty-four attempts all came out looking great, but not a single one of them would collapse and stay collapsed.

Eventually, [Eric] went back to the drawing board and played with the angles of the flex points, the thickness of the living hinges, and the wall thicknesses, which have to be strong enough to stay collapsed.

For attempt #25, [Eric] took the part out of the mold about three hours in and tried curing it in the collapsed state. Persistence paid off, and the part finally collapses and stays that way. Get yourself some popcorn and check out the fail-fest after the break. You know what we always say — fail fast, fail often.

[Eric] has made many molds both from silicone and for silicone. Some of them are really big!

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Extreme Canine Mask For Protection From Foxtails

July 4, 2021 by Danie Conradie 33 Comments

Our canine partners are fortunately not affected by the current global pandemic, but it turns out there are other dangers that might necessitate them to wearing masks: Foxtail seeds. After getting a $400 vet bill for extracting a foxtail from his dog, [Hildeguard]’s ear, [Amos Dudley] decided to take the threat seriously and made her a form-fitting 3D printed mask.

The only commercial solution [Amos] could find was the “OutFox Field Guard”, which is a $50 vinyl-coated mesh bag that covers the dog’s entire head. It had the unfortunate side effects of causing some other dogs to try and rip it off and does not allow easy access to the mouth for treats or balls. [Hilde]’s custom mask was designed in CAD after creating a rough 3D scan of her head with an iPhone app. The bottom is open to allow [Hilde] to freely use her mouth, while the nose and ears holes are covered with mesh. Custom heat-formed polycarbonate lenses cover the eye holes. The mask itself was printed using Draft resin, and the inside was padded with a thin layer of foam. It might also be possible to create a silicone version using a 3D-printed mold. The top features an integrated GoPro mount, and we can’t help but wonder what other electronic upgrades could be fitted to this sci-fi-looking mask.

In the field, the mask worked well and did not seem to bother [Hilde]. Unfortunately, it did not solve the problem of other dogs trying to rip it off at the park, so for the moment [Amos] is only using it for more solitary activities like hiking.

It doesn’t look like [Amos] is struggling in that department, but if you need some help burning of your dog’s energy, you can always built them a 3D printed automatic ball launcher.

3D Zoetrope Uses Illusion To Double The Frames

July 3, 2021 by Kristina Panos 10 Comments

Although film and animation have come quite a long way, there’s still something magical about that grandaddy of them all, the zoetrope. Thanks to persistence of vision, our eyes are fooled into seeing movement where there is none, only carefully laid-out still pictures strobing under the right lighting.

After four months of research, CAD, prototyping, and programming, [Harrison McIntyre] has built a 3D zoetrope that brings a gif to glorious physical life (video, embedded below). All the image pieces are printed and move under a fancy backlight that [Harrison] borrowed from work. It works essentially the same as a 2D zoetrope, as long as you get the spacing juuuuust right. 360° divided by 20 frames comes out to 18° per frame. So a motor spins the disk around, and every 18°, the light pulses for one millisecond and then turns off until the next frame is in position.

The really interesting thing is that there are actually more than 20 frames at play here. If you follow a single character through the loop, it takes 46 frames to complete the animation thanks to something 3D zoetrope pioneer [Kevin Holmes] dubbed ‘animation multiplexing‘, which in [Harrison]’s example, is easily explained as a relay race in which all runners run their section at the same time, creating the illusion of constant motion.

There’s more than one way to use a 3D printer to create a zoetrope, and we doubt we would have ever thought of this one that squashes four dimensions into three.

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Machine-Vision Archer Makes You The Target, If You Dare

June 30, 2021 by Dan Maloney 6 Comments

We’ll state right up front that it’s a really, really bad idea to let a robotic archer shoot an apple off of your head. You absolutely should not repeat what you’ll see in the video below, and if you do, the results are all on you.

That said, [Kamal Carter]’s build is pretty darn cool. He wisely chose to use just about the weakest bows you can get, the kind with strings that are basically big, floppy elastic bands that shoot arrows with suction-cup tips and are so harmless that they’re intended for children to play with and you just know they’re going to shoot each other the minute you turn your back no matter what you told them. Target acquisition is the job of an Intel RealSense depth camera, which was used to find targets and calculate the distance to them. An aluminum extrusion frame holds the bow and adjusts its elevation, while a long leadscrew and a servo draw and release the string.

With the running gear sorted, [Kamal] turned to high school physics for calculations such as the spring constant of the bow to determine the arrow’s initial velocity, and the ballistics formula to determine the angle needed to hit the target. And hit it he does — mostly. We’re actually surprised how many on-target shots he got. And yes, he did eventually get it to pull a [William Tell] apple trick — although we couldn’t help but notice from his, ahem, hand posture that he wasn’t exactly filled with self-confidence about where the arrow would end up.

[Kamal] says he drew inspiration both from [Mark Rober]’s dart-catching dartboard and [Shane Wighton]’s self-dunking basketball hoop for this build. We’d say his results put in him good standing with the skill-optional sports community.

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Garage Semiconductor Fab Gets Reactive-Ion Etching Upgrade

June 29, 2021 by Dan Maloney 21 Comments

It’s a problem that few of us will likely ever face: once you’ve built your first homemade integrated circuit, what do you do next? If you’re [Sam Zeloof], the answer is clear: build better integrated circuits.

At least that’s [Sam]’s plan, which his new reactive-ion etching setup aims to make possible. While his Z1 dual differential amplifier chip was a huge success, the photolithography process he used to create the chip had its limitations. The chemical etching process he used is a bit fussy, and prone to undercutting of the mask if the etchant seeps underneath it. As its name implies, RIE uses a plasma of highly reactive ions to do the etching instead, resulting in finer details and opening the door to using more advanced materials.

[Sam]’s RIE rig looks like a plumber’s stainless steel nightmare, in the middle of which sits a vacuum chamber for the wafer to be etched. After evacuating the air, a small amount of fluorinated gas — either carbon tetrafluoride or the always entertaining sulfur hexafluoride — is added to the chamber. A high-voltage feedthrough provides the RF energy needed to create a plasma, which knocks fluorine ions out of the process gas. The negatively charged and extremely reactive fluorine ions are attracted to the wafer, where they attack and etch away the surfaces that aren’t protected by a photoresist layer.

It all sounds simple enough, but the video below reveals the complexity. There are a lot of details, like correctly measuring vacuum, avoiding electrocution, keeping the vacuum pump oil from exploding, and dealing with toxic waste products. Hats off to [Sam’s dad] for pitching in to safely pipe the exhaust gases through the garage door. This ties with [Huygens Optics]’s latest endeavor for the “coolest things to do with fluorine” award.

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