Monoprice Mini Delta Review

August 21, 2017 by Brian Benchoff 82 Comments

For the last year or so, Monoprice has been teasing their follow-up to the fantastic $200 MP Select Mini. This is the $150 mini delta printer. We got a look at it last January at CES, it was on display at the Bay Area Maker Faire last May. Now there’s one on the Hackaday review desk.

Over the last few years, 3D printing has settled down into what most of us expected way back in 2010. No, not everyone wants, or arguably needs, a 3D printer on their desks. This is a far cry from the hype of a few years ago, leaving us with what we have today. 3D printers are just tools, much like a drill press or a laser cutter.

With that said, there still are some fantastic advances in 3D printing coming down from on high. Prusa will be shipping the 4-color multi-extruder add-on for the i3 Mk 2 shortly, and somehow or another we have infinite build volume printers. Still, there’s space to democratize 3D printing, and an opportunity for someone to release a very cheap, very good printer.

Monoprice was kind enough to send me a review unit of the MP Mini Delta before it officially hit their website. This is one of the first off the production line, alongside the few hundred pre ordered on an Indiegogo campaign earlier this year. Does this printer live up to expectations? It sure does, and that’s not just because it’s a $150 printer.

This would be an excellent printer at three times the price, and evidence enough that 3D printing is changing from a weird hobbyist thing to a proper tool.

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Analysing 3D Printer Songs For Hacks

August 20, 2017 by Inderpreet Singh 8 Comments

3D printers have become indispensable in industry sectors such as biomedical and manufacturing, and are deployed as what is termed as a 3D print farm. They help reduce production costs as well as time-to-market. However, a hacker with access to these manufacturing banks can introduce defects such as microfractures and holes that are intended to compromise the quality of the printed component.

Researchers at the Rutgers University-New Brunswick and Georgia Institute of Technology have published a study on cyber physical attacks and their detection techniques. By monitoring the movement of the extruder using sensors, monitored sounds made by the printer via microphones and finally using structural imaging, they were able to audit the printing process.

A lot of studies have popped up in the last year or so including papers discussing remote data exfiltration on Makerbots that talk about the type of defects introduced. In a paper by [Belikovetsky, S. et al] titled ‘dr0wned‘, such an attack was documented which allowed a compromised 3D printed propeller to crash a UAV. In a follow-up paper, they demonstrated Digital Audio Signing to thwart Cyber-physical attacks. Check out the video below.

In this new study, the attack is identified by using not only the sound of the stepper motors but also the movement of the extruder. After the part has been manufactured, a CT scan ensures the integrity of the part thereby completing the audit.

Disconnected printers and private networks may be the way to go however automation requires connectivity and is the foundation for a lot of online 3D printing services. The universe of Skynet and Terminators may not be far-fetched either if you consider ambitious projects such as this 3D printed BLDC motor. For now, learn to listen to your 3D printer’s song. She may be telling you a story you should hear.

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Simple 3D-Printed Circuitry

August 4, 2017 by John Baichtal 12 Comments

One of the problems encountered thus far with 3D-printing circuits with conductive filament is that it doesn’t really bond to anything, let alone solder, so how does one use it?

[mikey77] wrote an Instructable showing how to print circuit boards and create simple circuits, using shape of the plastic as a way to control the circuit. We like how he used using the flexible nature of the filament to make buttons, with two layers of conductive material coming together with the press of a finger.

He also created a linear potentiometer with a 3D-printed wiper that increases the ohms of the connection the farther it’s pushed. The filament doesn’t have the same conductivity as copper so [mikey] was able make resistors by stringing pieces of conductive plastic between two leads. There are also some hexagonal touch pads that turned out very nice.

We’ve published a lot of posts about DIY circuitry, including a previous effort of [mikey]’s, 3D-printed solderless circuits, plus another post about printing point-to-point circuits on a 3D printer.

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Using Nanotubes To Strengthen 3D Prints

June 30, 2017 by Lewin Day 14 Comments

3D printing has brought the production of plastic parts to the desktops and workshops of makers the world over, primarily through the use of FDM technology. The problem this method is that when squirting layers of hot plastic out to create a part, the subsequent vertical layers don’t adhere particularly well to each other, leading to poor strength and delamination problems. However, carbon nanotubes may hold some promise in solving this issue.

A useful property of carbon nanotubes is that they can be heated with microwave energy. Taking advantage of this, researchers coated PLA filament in a polymer film containing carbon nanotubes. As the layers of the print are laid down, the nanotubes are primarily located at the interface between the vertical layers. By using microwaves to heat the nanotubes, this allows the print to be locally heated at the interface between layers, essentially welding the layers together. As far as results are concerned, the team reports an impressive 275% improvement in fracture strength over traditionally printed parts.

The research paper is freely available, which we always like to see. There’s other methods to improve your print strength, too – you could always try annealing your printed parts.

[Thanks ????[d] ???? for the tip]

Animated Bathroom Sign

June 25, 2017 by Lewin Day 160 Comments

Once upon a time, pants were created. After a while, women were allowed to wear them too. This has made a lot of people happy and been widely regarded as a good thing. There is a problem, however – bathroom signage is largely predicated on the idea that there are two rigid genders which all humans must be sorted into, and they’re defined by whether you’re wearing pants or a dress. [Robb Godshaw], among others, disagrees with this, and set about building a gender fluid bathroom sign.

The project seeks to exploit the traditional symbols of “male” and “female” – the human figures wearing pants or a dress – by creating a sign that switches between the two every 15 seconds. This is likely to initially confuse – one might imagine the bathroom is actually changing its gender designation rapidly, forcing users to complete their business in an incredibly short timeframe. However, the message behind the project is to highlight the absurdity of defining gender by pants, colours, or indeed in a binary nature at all. [Robb] also helpfully points out that all humans have to pass waste, regardless of gender.

The sign is built with 3D-printed components, using a crank mechanism to actuate the moving parts. The mechanism is designed to give equal time to the pants and dress configurations. [Robb] shares the important details necessary to replicate the build, such as how to assemble the metal crank pin insert with a paperclip and a lighter. It’s particularly tidy the way the mechanism is integrated into the parts themselves. In true hacker style, the motor is a standard microwave oven turntable motor, which can be harvested easily from a junk appliance and can be plugged straight into mains power to operate, if you know what you’re doing. If you don’t, check out our primer on the topic.

Overall, the project is a great use of hacker techniques, like 3D printing and harvesting parts, to make a statement and start a conversation, while being fun, to boot. We’ve also seen some of [Robb]’s work before, like this giant hamster wheel for people. Video after the break.

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Hackaday Prize Entry: A 3D Printer Management System

June 24, 2017 by Brian Benchoff 23 Comments

Since the first desktop 3D printers, people have been trying to figure out a way to manage desktop 3D printers and turn them into tiny little automated factories. One of the first efforts was a conveyor belt build plate that was successfully used by MakerBot until it wasn’t anymore. Octoprint has been a boon for anyone who wants to manage a few printers, but that’s only half the solution.

For his Hackaday Prize entry, [Mike] has come up with a solution that turns a desktop 3D printer into a completely automated factory. Not only does this project take care of removing the part from the bed when the print is done, it also manages a web-based print queue. It is the simplest way to manage a printer we’ve ever seen, and it’s a great entry for the Hackaday Prize.

First up, the software stack. [Mike] has developed a web-based queue and slicing software that ingests 3D models and spits out Gcode to a printer. This, really, is nothing new. Octoprint does it, Astroprint does it, and even a few 3D printers have this capability. This is only one part of the project though, although it is geared more as a maker space management software than simply a dedicated 3D printer controller.

You can’t have an automated mini factory without an automated build plate, though, and here [Mike] has come up with something really great. His solution for dispensing prints after they’re completed is brilliant in its simplicity. All you need to do is drop the floor out from underneath the print. [Mike]’s solution is a trap door print bed. At the beginning of the print, an inkjet printer spits out a piece of paper, with a few lines of text, onto the print bed. When the print is finished, a stepper motor unwinds a cable, and a trap door opens up underneath the print. The part drops into a bin, the door closes, and the next print is loaded up in the queue. It’s brilliantly simple.

You can check out [Mike]’s demo of this system after the break. It’s awesome and so sublimely simple we’re shocked no one has thought of this before.

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Reverse Engineering The Monoprice Printer

June 20, 2017 by Brian Benchoff 33 Comments

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.

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