A 3D Printed Kinematic Camera Mount

[Enginoor] is on a quest. He wants to get into the world of 3D printing, but isn’t content to run off little toys and trinkets. If he’s going to print something, he wants it to be something practical and ideally be something he couldn’t have made quickly and easily with more traditional methods. Accordingly, he’s come out the gate with a fairly strong showing: a magnetic Maxwell kinematic coupling camera mount.

If you only recognized some of those terms, don’t feel bad. Named for its creator James Clerk Maxwell who came up with the design in 1871, the Maxwell kinematic coupling is self-orienting connection that lends itself to applications that need a positive connection while still being quick and easy to remove. Certainly that sounds like a good way to stick a camera on a tripod to us.

But the Maxwell design, which consists of three groves and matching hemispheres, is only half of the equation. It allows [enginoor] to accurately and repeatably line the camera up, but it doesn’t have any holding power of its own. That’s where the magnets come in. By designing pockets into both parts, he was able to install strong magnets in the mating faces. This gives the mount a satisfying “snap” when attaching that he trusts it enough to hold his Canon EOS 70D and lens.

[enginoor] says he could have made the holes a bit tighter for the magnets (thereby skipping the glue he’s using currently), but otherwise his first 3D printed design was a complete success. He sent this one off to Shapeways to be printed, but in the future he’s considering taking the reins himself if he can keep coming up with ideas worth committing to plastic.

Of course we’ve seen plenty of magnetic camera mounts in the past, but we really like the self-aligning aspect of this design. It definitely seems to fit the criterion for something that would otherwise have been difficult to fabricate if not for 3D printing.

Many Ways to Drive a Small Motor

Tiny motors used for haptic feedback and vibration come in a variety of shapes and sizes. The most familiar is the “eccentric rotating mass” (ERM) variety which just spins an imbalanced weight on a small motor and comes packaged in two form factors. The classic is the pager “pager motor” which just looks like a tiny, adorable motor and the squat cylindrical “pancake style”. ERMs are simple to use but provide imprecise response when compared to their new-age cousin the “linear resonant actuator”. Unlike the motor in an ERM, LRAs are typically an enclosed mass on a spring placed near a coil which pushes the mass back and forth. The name LRA might not be familiar but Apple’s branded implementation, the Taptic Engine, might be a little more recognisable.

[Precision Microdrives] is a vendor of these sorts of devices who happens to have a pleasantly approachable set of application notes covering any conceivable related topic. A great place to start is this primer on ways to drive motors with constant voltage in a battery powered environment. It starts with the most simple option (a voltage divider, duh) and works through a few other options through using an LDO or controller.

If you’re thinking about adding haptics to a project and are wondering what kind of actuator to use (see: the top of this post) AB-028 is a great resource. It has a thorough discussion on the different options available and considerations for mounting location, PCB attachment, drive modes, and more. Digging around their site yields some other interesting documents too like this one on mounting to fabric and other flexible surfaces. Or this one on choosing PWM frequencies.

3D Print Springs With Hacked GCode

If you’ve used a desktop 3D printer in the past, you’re almost certainly done battle with “strings”. These are the wispy bits of filament that harden in the air, usually as the printer’s nozzle moves quickly between points in open air. Depending on the severity and the material you’re printing with, these stringy interlopers can range from being an unsightly annoyance to triggering a heartbreaking failed print. But where most see an annoying reality of pushing melted plastic around, [Adam Kumpf] of Makefast Workshop sees inspiration.

Noticing that the nozzle of their printer left strings behind, [Adam] wondered if it would be possible to induce these mid-air printing artifacts on demand. Even better, would it be possible to tame them into producing a useful object? As it turns out it is, and now we’ve got the web-based tool to prove it.

As [Adam] explains, you can’t just load up a 3D model of a spring in your normal slicer and expect your printer to churn out a useful object. The software will, as it’s designed to do, recognize the object can’t be printed without extensive support material. Now you could in theory go ahead and print such a spring, but good luck getting the support material out.

The trick is to throw away the traditional slicer entirely, as the layer-by-layer approach simply won’t work here. By manually creating GCode using carefully tuned parameters, [Adam] found it was possible to get the printer to extrude plastic at the precise rate at which the part cooling fan would instantly solidify it. Then it was just a matter of taking that concept and applying it to a slow spiral motion. The end result are functional, albeit not very strong, helical compression springs.

But you don’t have to take their word for it. This research has lead to the creation of an online tool that allows you to plug in the variables for your desired spring (pitch, radius, revolutions, etc), as well as details about your printer such as nozzle diameter and temperature. The result is a custom GCode that (hopefully) will produce the desired spring when loaded up on your printer. We’d love to hear if any readers manage to replicate the effect on their own printers, but we should mention fiddling with your printer’s GCode directly isn’t without its risks: from skipping steps to stripped filament to head crashes.

The results remind us somewhat of the 3D lattice printer we featured a couple of years back, but even that machine didn’t use standard FDM technology. It will be interesting to see what other applications could be found for this particular technique.

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Mini LEGO Technic Tank Patrols Your Desk Under ESP32 Control

We probably don’t have to tell the readers of Hackaday that LEGO isn’t just for kids; we’ve seen plenty of projects that live in an enclosure made of the multi-color bricks, and let’s not even get started on the Mindstorms builds we’ve seen over the years. But while LEGO (and especially the Technic product line) is fine for prototyping and putting together quick projects, the stock electronic components aren’t exactly top of the line. Which is why [Jason Kirsons] has been working on bridging the gap between LEGO and “real” parts.

His LEGO Technic tank is a perfect example of this principle. While the tank design itself is standard LEGO fare, he’s gone all in on the electronics. With an Adafruit Feather ESP32, custom motor controller board, and NEMA 8 steppers with 3D printed Technic adapters, this little tank has a lot more going on under the hood than you might expect. While this project is more a proof of concept than anything, the methods [Jason] demonstrates might be something to consider the next time you’re building with Billund’s best.

[Jason] chose the Feather ESP32 because of its small size, but you could get away with a generic board if you’re not trying to compress everything down into such a small footprint. Of course, if you go with another board you won’t be able to use the PCB he’s designed which attaches to the Feather and holds four Pololu DRV8835 motor drivers.

Easily the most broadly applicable element of this project is the work [Jason] has done designing adapter plates that let you use NEMA 8 motors with LEGO Technic parts. He’s put the adapters up on Thingiverse, for anyone looking for a drop-in solution to give their Technic creations a bit more oomph (technical term).

LEGO has a long history with hackers and makers. We’ve covered some absolutely incredible projects built with the famous construction set, and we don’t see any sign of it slowing down in the future.

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New AVR-IOT Board Connects to Google

Readers of Hackaday are no strangers to using a microcontroller to push data to WiFi. Even before the ESP8266 there were a variety of ways to do that. Now Microchip is joining the fray with a $29 board called the AVR-IOT WG that contains an 8-bit ATmega4808, a WiFi controller, and hardware-based crypto chip for authenticating with Google Cloud.

The board has a section with a USB port for charging a battery and debugging that looks like it is made to cut away. There are a number of LEDs and buttons along with a light sensor and a temperature sensor. It feels like the goal here was to pack as many Microchip parts onto a single dev board as possible. You’ll find the ATmega4808 as the main controller, an ATWINC1510 WiFi controller (a castellated module reminiscent of the ESP8266), the ATECC608A cryptographic co-processor, MCP73871 LiPo charger, MIC33050 voltage regulator, and an MCP9808 temperature sensor. We can’t find much info about the “nEDBG Programmer/Debugger” chip. If you’ve used it on one of a handful of other dev board, let us know in the comments about off-board programming and other possible hacks.

Naturally, the board works with AVR Studio or MPLAB X IDE (Microchip bought Atmel, remember?). Of course, Atmel START or MPLAB Code Configurator can configure the devices, too. There’s also an AVR-IoT-branded website that lets you use Google cloud to connect your device for development. The headers along the top and bottom edges are compatible with MicroElektronika Click boards which will make anyone with a parts bin full of those happy.

Looks like you can pick up the Microchip boards now from the usual places. From reading what Microchip is saying, they would like to position this as the “IoT Arduino” — something someone without a lot of experience could pick up and use to pipe data into Google cloud. While that’s probably good, it isn’t that hard to use an ESP-device to do the same thing using the Arduino IDE and then you have a 32-bit processor and you can use whatever cloud vendor you want. Sure, it would be a little more work, so maybe that’s where this offering will appeal.

On the plus side, we really liked that there was a battery option with a charger already on board — it seems like that’s something we always have to add anyway. It may be buried in the documentation, but the user’s guide and the technical guide didn’t appear to have an average and maximum current draw specified, so battery life is an open question, although the video says “low power.”

Although it isn’t quite the same thing, we’ve seen ESP8266’s talk to Google servers for interfacing with Google Home. And while it is on the Amazon cloud, we’ve even seen a 6502 up there.

 

 

You’ll Flip for This 7404 IC Motherboard Fix

We often lament that the days of repairable electronics are long gone. It used to be you’d get schematics for a piece of gear, and you could just as easily crack it open and fix something as the local repairman — assuming you had the knowledge and tools. But today, everything is built to be thrown away when something goes wrong, and you might as well check at the end of a rainbow if you’re searching for a circuit diagram for a new piece of consumer electronics.

But [Robson] writes in with an interesting story that gives us hope that the “old ways” aren’t gone completely, though they’ve certainly changed for the 21st century. After blowing out his laptop’s USB ports when he connected a suspect circuit, he was desperate for a fix that would fit his student budget (in other words, nearly zero). Only problem was that he had no experience fixing computers. Oh, and it takes months for his online purchases to reach him in Brazil. Off to a rocky start.

His first bit of luck came with the discovery he could purchase schematics for his laptop online. Now, we can’t vouch for the site he used (it sure isn’t direct from Dell), but for under $5 USD [Robson] apparently got complete and accurate schematics that let him figure out what part was blown on the board without even having to open up the computer. All he had to do was order a replacement IC (SY6288DAAC), and solder it on. It took two months for the parts to arrive, and had to do it with an iron instead of a hot air station, but in the end, he got the part installed.

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Hacking The ZH03B Laser Particle Sensor

Laser particle detectors are a high-tech way for quantifying whats floating around in the air. With a fan, a laser, and a sensitive photodetector, they can measure smoke and other particulates in real-time. Surprisingly, they are also fairly cheap, going for less than $20 USD on some import sites. They just need a bit of encouragement to do our bidding.

[Dave Thompson] picked up a ZH03B recently and wanted to get it working with his favorite sensor platform, Mycodo. With a sprinkling of hardware and software, he was able to get these cheap laser particle sensors working on his Raspberry Pi, and his work was ultimately incorporated upstream into Mycodo. Truly living the open source dream.

The ZH03B has PWM and UART output modes, but [Dave] focused his attention on UART. With the addition of a CP2102 USB-UART adapter, he was able to connect it to his Pi and Mac, but still needed to figure out what it was saying. He eventually came up with some Python code that lets you use the sensor both as part of a larger network or service like Mycodo and as a stand-alone device.

His basic Python script (currently only tested on Linux and OS X), loops continuously and gives a running output of the PM1, PM2.5, and PM10 measurements. These correspond to particles with a diameter of 1, 2.5, and 10 micrometers respectively. If you want to plug the sensor into another service, the Python library is a bit more mature and lets you do things like turn off the ZH03B’s fan to save power.

These sensors are getting cheap enough that you can build distributed networks of them, a big breakthrough for crowd-sourced environmental monitoring; especially with hackers writing open source code to support them.