Reverse Engineering The Monoprice Printer

When the Monoprice MP Select Mini 3D printer was released last year, it was a game changer. This was a printer for $200, yes, but it also held a not-so-obvious secret: a 3D printer controller board no one had ever seen before powered by a 32-bit ARM microcontroller with an ESP8266 handling the UI. This is a game-changing set of electronics in the world of 3D printing, and now, finally, someone is reverse engineering it.

[Robin] began the reverse engineering by attaching the lead of an oscilloscope to the serial line between the main controller and display controller. The baud rate is weird (500 kHz), but apart from that, the commands readily appear in human-parsable text. There is a web server built into the MP Mini printer, and after inspecting the web page that’s served up from this printer, [Robin] found it was possible to send G-code directly from the controller board, get a list of files on the SD card, and do everything you would want to do with a 3D printer.

After deconstructing the circuit on the display board, [Robin] found exactly what you would expect from such a simple board: an SPI display driven by an ESP, and a big flash chip sitting off to the side. [Robin] found the the model of the display, and quickly built a project on Platform.io to draw text to the LCD. This isn’t the end of the project – there’s still a lot that must be done before this printer is squirting out parts with custom firmware.

While this isn’t a hack of the driver board inside the MP Mini, that’s not really a problem. The motor driver board in this printer doesn’t really need any changes, and was already ahead of its time when this printer was released last year. As with most things, the UI is the weak point, and upgrading the firmware and built-in web server for this printer is the best way forward.

[Robin] put together a truly phenomenal video of how he reverse engineered this display controller. You can check that out below.

Continue reading “Reverse Engineering The Monoprice Printer”

Holman is Your Phone’s Best Friend

Let’s get something straight right up front: this isn’t much of an electronics project. But it is a very artistic 3D printing project that contains some electronics. [Sjowett] used an off-the-shelf class D amplifier with BlueTooth input to create a simple BlueTooth speaker with a subwoofer. As you can see from the pictures, woofer is exactly the term to use, too.

The clever mechanical design uses 3D printing and common metric PVC pipe. That’s a great technique and resulted in a very clean and professional-looking build. If you don’t have easy access to metric pipe, you could print the pipes, but it will take longer and might not look quite as good.

Continue reading “Holman is Your Phone’s Best Friend”

Annealing Plastic For Stronger Prints

Much fuss has been made over the strength of 3D printed parts. These parts are obviously stronger in one direction than another, and post processing can increase that strength. What we’re lacking is real data. Luckily, [Justin Lam] has just the thing for us: he’s tested annealed printed plastics, and the results are encouraging.

The current research of annealing 3D printed parts is a lot like metallurgy. If you put a printed part under low heat — below the plastic’s glass transition temperature — larger crystals of plastic are formed. This research is direct from the Society of Plastics Engineers, and we’re assuming they know more about material science than your average joe. These findings measured the crystallinity of a sample in relation to both heat and time, and the results were promising. Plastic parts annealed at a lower temperature can attain the same crystallinity, and therefore the same strength, if they’re annealed for a longer time. The solution is simple: low and slow is the best way to do this, which sounds a lot like sous vide.

A while back, [Justin] built a sous vide controller for the latest cooking fad. The idea behind a sous vide controller is to heat food in a water bath at a lower temperature, but for a longer time. The result here is the most tender steaks you’ll ever have, and also stronger 3D printed parts. In his test, [Justin] printed several rectangular samples of PLA, set the temperature to 70°C, and walked away for a few hours. The samples annealed in the water bath were either cooled quickly or slowly. The test protocol also included measuring the strength in relation to layer height. The test jig consisted of a bathroom scale, a drill press, and a slot head screwdriver bit.

Although the test protocol is slightly questionable, the results are clear: annealing works, but only if the part is printed at a low layer height. However, parts with larger layer heights had a higher maximum stress. Is this helpful for the home prototyper? That depends. The consensus seems to be that if you’re at the mechanical limits of a 3D printed part, you might want to think about more traditional manufacturing. That’s just common sense, but there’s always room to push the envelope of 3D printing.

Biped Bob Walks and Dances

If you have a few servo motors, an Arduino, and a Bluetooth module, you could make Biped Bob as a weekend project. [B. Aswinth Raj] used a 3D printer, but he also points out that you could have the parts printed by a service or just cut them out of cardboard. They aren’t that complex.

Each of Bob’s legs has two servo motors: one for the hip and one for the ankle. Of course, the real work is in the software, and the post breaks it down piece-by-piece. In addition to the Arduino code, there’s an Android app written using Processing. You can build it yourself, or download the APK. The robot connects to the phone via BlueTooth and provides a simple user interface to do a few different walking gaits and dances. You can see a few videos of Biped Bob in action, below.

This wouldn’t be a bad starter project for a young person or anyone getting started with robotics, especially if you have a 3D printer. However, it is fairly limited since there are no sensors. Then again, that could be version two, if you were feeling adventurous.

We have mixed feelings about the BlueTooth control. BlueTooth modules are cheap and readily available, but so are ESP8266s. It probably would not be very difficult to put Bob on WiFi and let him serve his own control page to any web browser.

If Bob meets Jimmy, he may find himself envious. However, Jimmy would be a little more challenging to build. We’ve actually seen quite a few walking ‘bots over the years. Continue reading “Biped Bob Walks and Dances”

PrusaControl: The Beginner’s Slicer

There are two main applications for managing 3D prints and G-Code generation. Cura is a fantastic application that is seeing a lot of development from the heavy hitters in the industry. Initially developed by Ultimaker,  Lulzbot has their own edition of Cura, It’s the default software packaged with thousands of different printers. Slic3r, as well, has seen a lot of development over the years and some interesting hacks. Do you want to print non-planar surfaces? Slic3r can do that. Slic3r and Cura are two sides of the CAM part of the 3D printing coin, although Cura is decidedly the prettier side.

The ability to combine the extensibility of Slic3r with the user interface of Cura has been on our wish list for a while now. It’s finally time. [Josef Prusa] has released PrusaControl, a 3D printing CAM solution that combines the best of Slic3r into a fantastic, great looking package. What are the benefits? What’s it like? Check that out below.

Continue reading “PrusaControl: The Beginner’s Slicer”

3D Printed Radiation Patterns

Radiation patterns for antennas can be utterly confusing, especially when presented in two dimensions, as they usually are. Fear not, [Hunter] has your back with 3D printed and color-coded radiation patterns.

In the field of antenna design, radiation patterns denote the relationship between the relative strength of radio waves emitted from antennas and the position of a receiver/transmitter in 3D space. In practice, probes can be used to transmit/receive from documented locations around an antenna while recording signal intensity, allowing researchers and engineers to determine the characteristics of arcane antennas. These measurements are normally expressed as two-dimensional slices of three-dimensional planes. Naturally, this sometimes (often) complex geometry is difficult for all but the most spatially inclined to mentally conceptualize with only the assistance of a 2D drawing. With computers came 3D models, but [Hunter] wasn’t satisfied with a model on a screen: they wanted something they could hold in their hands.

To that end, [Hunter] simulated several different antenna structures, cleaned up the models for 3D printing, and 3D printed them in color sandstone, and the end result is beautiful. By printing in colored sandstone through Shapeways, [Hunter] now has roughly walnut-sized color-coded radiation patterns they can hold in their hand. To save others the work, [Hunter] has posted his designs on Shapeways at Ye Olde Engineering Shoppe. So far, he has a horn antenna, dipole, inset fed patch antenna and a higher order mode of a patch antenna, all of which are under 15.00USD. Don’t see the antenna radiation pattern of your dreams? Fret not, [Hunter] is looking for requests, so post your ideas down in the comments!

Further, beyond the immediate cool factor, we can see many legitimate uses for [Hunter’s] models, especially in education. With more and more research promoting structural rather than procedural learning, [Hunter’s] designs could easily become a pedagogical mainstay of antenna theory classes in the future. [Hunter] is not the only one making the invisible visible, [Charles] is mapping WiFi signals in three dimensions.

Video after the break.

Continue reading “3D Printed Radiation Patterns”

Hackaday Prize Entry: Printing Bones

You would be forgiven to think that 3D printing is only about rolls of filament and tubs of resin. The fact is, there are many more 3D printing technologies out there. Everything from powders to paper can be used to manufacture a 3D model. [Jure]’s Hackaday Prize entry is meant to explore those weirder 3D manufacturing techniques. This is a printer that lays down binder over a reservoir of powder, slowly building up objects made out of minerals.

The key question with a powder printer is exactly what material this printer will use. For this project, [Jure] is planning on printing with hydroxyapatite, a mineral that makes up about 70% of bones by weight. Printing bones — yes, they do that — is quite expensive and has diverse applications.

The design of this printer is about what you would expect. It’s a Cartesian design with a roller to distribute powder, a piston to drop the part down into the frame, and an industrial inkjet printhead designed for wide format printers. It’s a fantastic piece of work and one of the better powder printers we’ve seen, and we can’t wait to see what [Jure] is able to produce with this.