Analog Shield And PCB Quadcopter

May 30, 2014 by Mike Szczys 2 Comments

[youtube=https://www.youtube.com/watch?v=gXW76ESIv6k&w=580]

We spent a little bit of time at the TI booth at Maker Faire to film a pair of interviews. The first is with [Bill Esposito] who is grinding away on his PhD. at Stanford. He’s showing off an Analog Shield for Arduino. He describes it as “an attempt to bring the analog bench to an Arduino shield”. We think this is a fantastic idea as most who are learning digital electronics through Arduino have little or no experience with analog circuitry. This is a nice gateway drug for the concepts.

The analog shield has a supply good for +/- 7.5 volts, 4-channel ADC, 4-channel DAC, and gets 100k samples at 16-bits. He showed us a spectrum analyzer using Fast Fourier Transform on the incoming signal from a microphone. He also built a function generator around the shield. And finally a synthesizer which plays MIDI files.

In the second half of the video we take a look at [Trey German’s] work on a PCB-based quadcopter. His goal is to reduce the power consumption which will equate to longer flying times. To this end he chose the DRV8312 and a Piccolo to control each sensorless, brushless DC motor. The result should be 10% lower power consumption that his previous version.

A Huge, Lightweight Wooden Quadrotor

May 27, 2014 by Brian Benchoff 15 Comments

quad_1

[Robert] once built a quadcopter frame by sawing laminate floor tile. It worked, we’re taking the lack of pictures of this build as evidence of how ugly it was. His latest design used a much better looking material – laser cut plywood – and the finished product is very strong and lightweight, even compared to commercial frames made with glass or carbon fiber and epoxy.

Although the design went smoothly thanks to some Solidworks skills, actually cutting the frame from 3mm birch ply resulted in a few issues. The cheap laser cutter used for cutting include some bottom of the line software called LaserWorksV5. There is a kerf compensation feature, called ‘sew compensation’ in the software’s native Chinglish. The software would always crash whenever it tried to calculate the compensation for circles. [Robert] spent two hours figuring this problem out, and in the end needed to break out a piece of sand paper to get a nice interlocking fit.

The completed frame bolts together without any glue at all, and the best part about it is the weight – only 167 grams. Compare that to a similarly sized glass fiber frame, and [Robert]’s shaved at least 200 grams off his finished build.

Frankensteined X4 Quad Is Brought Back To Life

May 14, 2014 by Rich Bremer 14 Comments

x4 quadcopter wood frame

As kids we’ve all let a friend use a toy only to have it returned broken. That was such a bummer! At least that was years ago though…. well not for [Tom]. He had a Hubsan X4 mini quadcopter that he had crashed into all sorts of things. The little quad held up good against all of the beatings so [Tom] didn’t think too much about letting his pal take it for a test drive. Thirty seconds later, several separate pieces of the quad were laying in the dirt.

A new X4 was ordered but there was some time to kill waiting for it to show up. Since the electronics seemed to be intact and only the frame was broken [Tom] decided to try his hand at making a new frame. Keeping costs under control is an important part of any project and this one was no different. The frame would be made of cheap and rigid 5mm plywood. The only potential problem would be the weight. [Tom] cut out a piece of the plywood and weighed it, then measured the volume and calculated the density of the wood. The wood’s density was used to estimate the final weight of new plywood frame designs and shapes. This worked so well that the newly built quad only weighed more than the original by 0.31 grams, less than 1% increase in the total weight!

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A Quadcopter From Scratch

May 12, 2014 by Adam Fabio 13 Comments

Quadcopter

[AwesomeAwesomeness] wanted a low cost quadcopter, so he built one from scratch. Okay, not quite from scratch. [AA’s] cookie mix came in the form of an Arduino Uno and some motors. He started with motors and propellers from a Hubsan X4 quadcopter. Once the power system was specified, [AA] designed a frame, arms, and motor pods in Solidworks. He printed his parts out and had a sweet quadcopter that just needed a brain.

Rather than buy a pre-made control board, [AA] started with an Arduino Uno. An Arduino alone can’t source enough current to drive the Hubsan motors. To handle this, [AA] added a ULN2003A Darlington transistor array. The 2003A did work, but [AA] had some glitching issues. We think FETs would do much better in this application, especially when running PWM.

On the control side of things, [AA] added an MPU-6050 Triple Axis Accelerometer and Gyro breakout from SparkFun. The 6050 has 3 gyros and 3 accelerometers in one package. Plenty for a quadcopter.

All this left was the coding. Multicopters generally use Proportional-Integral-Derivative (PID) control loops to maintain stability in the air. [AA] used the Arduino PID library for his quadcopter. He actually created two PID instances – one for pitch and one for roll.

[AA] doesn’t have any videos of his quadcopter in action yet, and we’re guessing this is due in part to weight. Lifting an Uno, a perfboard, and a frame is a tall task for those motors. Going with a one of the many tiny Arduino’s out there would help reduce weight. In addition, [AA] could use a gear system similar to what is used in the Syma X series quadcopters. Stick with it – you’re on the right track!

Phenox: Wherein Quadcopters Get FPGAs

May 11, 2014 by Brian Benchoff 23 Comments

quad

The computing power inside a quadcopter is enough to read a few gyros and accelerometers, do some math, and figure out how much power to send to the motors. What if a quadcopter had immensely more computing power, and enough peripherals to do something cool? That’s what Phenox has done with a micro quad that is able to run Linux.

Phenox looks like any other micro quad, but under the hood things get a lot more interesting. Instead of the usual microcontroller-based control system, the Phenox features a ZINQ-7000 System on Chip, featuring an ARM core with an FPGA and a little bit of DDR3 memory. This allows the quad to run Linux, made even more interesting by the addition of two cameras (one forward facing, one down facing), a microphone, an IMU, and a range sensor. Basically, if you want a robotic pet that can hover, you wouldn’t do bad by starting with a Phenox.

The folks behind Phenox are putting up a Kickstarter tomorrow. No word on how much a base Phenox will run you, but it’ll probably be a little bit more than the cheap quads you can pick up from the usual Chinese retailers.

Videos below.

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Reading 2.4GHz Transmitters With An Arduino

May 10, 2014 by Brian Benchoff 11 Comments

Quad There are a lot of cheap quadcopter kits out there, sold ready to fly with a transmitter and battery for right around $50 USD. One of the more popular of these micro quads is the V2X2 series. They are, unfortunately not compatible with any other radio protocol out there, but [Alexandre] has managed to use the transmitter included with his V202 quad to send data to an Arduino.

Like most quads, the transmitter that came with [Alexandre]’s V202 operates on 2.4GHz. Listening in on that band required a little bit of hardware, in this case a nordic Semiconductors nRF24L01p. Attached to this chip is a regular ‘ol Arduino running a bit of code that includes [Alexandre]’s V202 library.

Right now, the build can detect if the quad is bound or not, and read the current position of the throttle, yaw, pitch, and roll, as well as all the associated trims. It’s just the beginnings of [Alexandre]’s project, but his eventual goal is to build an Arduino bot based on the code, complete with RC servos. Not bad for a transmitter that will be utterly useless when the microquad eventually breaks.

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Quadcopter Built From Recycled Motherboards

May 9, 2014 by Adam Fabio 18 Comments

A quadcopter built from a motherboard

[Eric] has figured out a great way to build quadcopters out of recycled computer motherboards. Multicopters come in all shapes and sizes these days. As we mentioned in the last issue of Droning On, they can be bought or built-in a multitude of materials as well. Drones have been built using materials as varied as wood, PVC pipe, carbon fiber, and aluminum.

One of the more common commercial materials is G10 fiberglass sheet. It’s stiff, strong, and relatively light. Printed circuit boards are generally made of FR-4 fiberglass, G10’s flame resistant cousin. It’s no wonder [Eric] had quadcopters in his eyes when he saw a pile of motherboards being thrown out at his university.

[Eric] used a heat gun and a lot of patience to get all the components off the motherboard. With a bit of care, most of the components can be saved for future hardware hacks. This is one step that’s best performed outside. Hot melting plastics, metals, and resin fumes aren’t the greatest things to inhale.

Computer motherboards being cut on a shopbot Clean PCBs in hand, [Eric] headed to his local TechShop. He drew his dead cat style frame in SolidWorks and cut it out on a ShopBot. While a high-end CNC cutter is nice, it’s not absolutely necessary. The fiberglass sheets could be cut with a rotary tool or a jigsaw. No matter how you cut it, be sure to wear a mask rated for fiberglass resins and some protective clothing. Fiberglass plate is nasty stuff to cut.

Once the upper and lower frame plates were cut, [Eric] completed his quad frame with some square wooden stock for arms. The final quad is a great flier, and spare parts are easy to source. Nice work on the recycling, [Eric]!

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