Where There’s Smoke, There’s A Knockoff 3D Printer

January 5, 2017 by 46 Comments

These days, it’s possible to buy clones of popular 3D printers from China for satisfyingly low prices. As always, you get what you pay for, and while usable, often they require some modification to reach their full potential. [g3ggo] recently laid down €270 for a clone of the Prusa i3 by Geeetech, knowing it would require some modifications for safety and performance.

First on the bill was a wobbly Z-axis, which was dealt with by printing some new parts designed to fix this issue which have already been developed by the community. Forums are your friend here – often an enterprising user will have already developed fixes for the most common issues, and if they haven’t, you can always step up to be the hero yourself. There was a darker problem lurking inside, though.

[g3ggo] began to wonder why the MOSFETs for the hot end were running so hot. It turned out to be an issue of gate drive – the FETs were only being driven with 5V, which for the given part, wasn’t enough to reach its lowest R_DS(on) and thus was causing the overheating issue. It gets worse, though – the heatsinks on the MOSFETs were bolted on directly without insulation, and sitting fractions of a millimeter above traces on the PCB. Unfortunately, with a small scratch to the soldermask, this caused a short circuit, destroying the hot end and MOSFETs and narrowly avoiding a fire. This is why you never leave 3D printers unattended.

The fix? Replacing the MOSFETs with a part that could deal with a 5V gate drive was the first step, followed by using insulating pads & glue to stop the heatsinks contacting the PCB. Now with the cooler running MOSFETs, there’s less chance of fire, and the mainboard’s cooling fan isn’t even required anymore. Overall, for a small investment in time and parts, [g3ggo] now has a useful 3D printer and learned something along the way. Solid effort!

ESP-ing A Philips Sound System.

January 5, 2017 by 42 Comments

IoT-ifying old stuff is cool. Or even new, offline stuff. It seems to be a trend. And it’s sexy. Yes, it is. Why are people doing this, you may ask: we say why not? Why shouldn’t a toaster be on the IoT? Or a drill press? Or a radio? Yes, a radio.

[Dr. Wummi] just added another device to the IoT, the Internet of Thongs as he calls it. It’s a Philips MCM205 Micro Sound System radio. He wanted to automate his radio but his original idea of building a setup with an infrared LED to remotely control it failed. He blamed it to “some funky IR voodoo”.  So he decided to go for an ESP8266 based solution with a NodeMCU. ESP8266 IR remotes have been known to work before but maybe those were just not voodoo grade.

After opening the radio up, he quickly found that the actual AM/FM Radio was a separate module. The manufacturer was kind enough to leave the pins nicely labelled on the mainboard. Pins labelled SCL/SDA hinted that AM/FM module spoke I²C. He tapped in the protocol via Bus Pirate and it was clear that the radio had an EEPROM somewhere on the main PCB. A search revealed a 24C02 IC in the board, which is a 2K I²C EEPROM. So far so good but there were other functionalities left to control, like volume or CD playing. For that, he planned to tap into the front push button knob. The push button had different resistors and were wired in series so they generated different voltages at the main board radio ADC Pins. He tried to PWM with the NodeMCU to simulate this but it just didn’t work.

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The World’s Lightest Brushless FPV Quadcopter

January 5, 2017 by 28 Comments

When a claim is made for something being the world’s lightest it is easy to scoff, after all that’s a bold assertion to make. It hasn’t stopped [fishpepper] though, who claims to have made the world’s lightest brushless FPV quadcopter. Weighing in at 32.4 grams (1.143 oz) it’s certainly pretty light.

The frame is a circular design cut from carbon-fiber-reinforced polymer, and on it are mounted four tiny brushless motors. In the center are the camera and battery on a 3D printed mount, as well as custom flight and speed controller boards. There are a series of posts detailing some of the design steps, and the result is certainly a capable aircraft for something so tiny. If you fancy experimenting with the design yourself, the files are available for download on the first page linked above.

There are two aspects to this build that make it interesting to us. First, the lightest in the world claim. We think someone will come along with something a bit lighter, and we can’t wait to see a lightest multirotor arms race. Good things come of technology races, which brings us to the second aspect. Governments are busy restricting the use of larger multirotors, to the extent that in some parts of the world all that will be available for non professionals will be sub-200g toy craft. Any project like this one which aims to push the boundaries of what is possible with smaller multirotors is thus extremely interesting, and we hope the community continue to innovate in this direction if only to make a mockery of any restrictions.

To get some idea of the sort of legislative measures we might be seeing, take a look at our coverage of a consultation in just one country.

Hands On With The First Open Source Microcontroller

January 5, 2017 by 148 Comments

2016 was a great year for Open Hardware. The Open Source Hardware Association released their certification program, and late in the year, a few silicon wizards met in Mountain View to show off the latest happenings in the RISC-V instruction set architecture.

The RISC-V ISA is completely unlike any other computer architecture. Nearly every other chip you’ll find out there, from the 8051s in embedded controllers, 6502s found in millions of toys, to AVR, PIC, and whatever Intel is working on are closed-source designs. You cannot study these chips, you cannot manufacture these chips, and if you want to use one of these chips, your list of suppliers is dependent on who has a licensing agreement with who.

We’ve seen a lot of RISC-V stuff in recent months, from OnChip’s Open-V, and now the HiFive 1 from SiFive. The folks at SiFive offered to give me a look at the HiFive 1, so here it is, the first hands-on with the first Open Hardware microcontroller.

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Python Solution To A Snake Cube Puzzle

January 5, 2017 by 11 Comments

Puzzles provide many hours of applied fun beyond any perfunctory tasks that occupy our days. When your son or daughter receives a snake cube puzzle as a Christmas gift — and it turns out to be deceptively complex — you can sit there for hours to try to figure out a solution, or use the power of Python to sort out the serpentine conundrum and use brute-force to solve it.

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Visualization Of A Phased Array Antenna System

January 5, 2017 by 39 Comments

Phased array antenna systems are at the cusp of ubiquity. We now see Multiple-Input Multiple-Output (MIMO) antenna systems on WiFi routers. Soon phased array weather radar systems will help to predict the weather and keep air travel safe, and phased array base stations will be the backbone of 5G which is the next generation of wireless data communication.  But what is a phased array antenna system?  How do they work?  With the help of 1024 LEDs we’ll show you.

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Acoustic Levitation With A Twist

January 5, 2017 by 27 Comments

Don’t blame us for the click-baity titles in the source articles about this handheld “acoustic tractor beam”. You can see why the popular press tarted this one up a bit, even at the risk of drawing the ire of Star Trek fans everywhere. Even the journal article describing this build slipped the “tractor beam” moniker into their title. No space vessel in distress will be towed by [Asier Marzo]’s tractor beam, unless the aliens are fruit flies piloting nearly weightless expanded polystyrene beads around the galaxy.

That doesn’t detract from the coolness of the build, revealed in the video below. There’s no tutorial per se, but an Instructables post is promised. Still, a reasonably skilled hacker will be able to replicate the results with ease straight from the video. Using mostly off the shelf hardware, [Marzo] creates a bowl-shaped phased array of ultrasonic transducers driven by an Arduino through a DC-DC converter and dual H-bridge driver board to boost the 40 kHz square waves from 5 Vpp to 70 Vpp. By controlling the phasing of the signals, the tractor beam can not only levitate small targets but also move them axially. It looks like a lot of fun.

Acoustic levitation is nothing new here – we’ve covered 3D acoustic airbending, as well as an acoustic flip-dot display. Being able to control the power of sound waves in a handheld unit is a step beyond, though.

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