5 reasons Raspberry Pi Zero is amazing

The Raspberry Pi Zero has been met with much criticism. The core complaint is the need for peripherals. Some complain that there are no audio outputs or inputs. Other complain that every interesting use case is for the internet of things (IoT), and IoT always requires WiFi. The least nonsensical complaint is that it does not have Ethernet, so you have to by a micro-USB Ethernet adaptor just to talk to it.

There are also valid complaints that a single core and 512MB of RAM are not enough for development and that . Lets face, the Rasperry Pi Zero is not going to bring computing to third world countries that can only afford to spend $5. The cost of peripherals brings the price too close to a Raspberry Pi 2. However, the Raspberry Pi Zero is great for budding makers.

1. Able to fit is small places

Continue reading 5 reasons Raspberry Pi Zero is amazing

PPM Output for FlySky i6

I recently rejoined the radio-controlled (RC) vehicle community. One of the first purchases that I had to make was a transmitter, and my budget was fairly small. I did not want to spend hundreds of dollars a new hobby that turns out to be a personal fad. Although used Spektrum receivers are a great value, I decided to buy a new FlySky FS-i6. This is a feature rich transmitter at an affordable price.

I wrongly assumed that every receiver would output PWM and that every flight controller would have PWM as an input. The Pixhawk does not have PWM inputs. It only supports PPM, SBUS and Spektrum serial inputs. I quick-like bought a PPM encoder, but it turns out that I should have done more research.

The FlySky FS-ia6B is compatible with the FlySky FS-i6, and it would have saved space and reduced wiring at a similar expense. I have now, and it is great!

GPS is a bad odometer, but could easily be better

GPS fitness bands and apps that can be used as odometers are a hot product for runners. Many runners are surprised to discover that these devices frequently overestimate distances run. How can a technology used for missile guidance be so inaccurate? Collegues may tell you that you are not running the tangents or corners correctly, but the answer is simple: missile guidance is based on position of the target, not distance.

GPS Odometer Using Differential Position

GPS is great at estimating your position in three dimensional space. It can often locate you within 10 feet, which is very impressive. However, the military has access to much better estimates using technology that removes atmospheric effects. Many blame the inaccuracy of their GPS odometer on these atmospheric effects and multipath noise, which do play a role, but the over estimation is better explained using basic algebra.

Continue reading GPS is a bad odometer, but could easily be better

New Topic: Deceptive Technology

“Disruptive technology” quickly transitioned from a meme to an investment strategy, but recent events demonstrate that the true disruption is not always the one that was advertised. For example, Theranos and uBeam have recently back pedaled on their disruptive claims. Stories like these are not breaking news to tech consumers. We buy tech products that fail to live up to their marketing hype every day.

To address these stories, I am introducing a new topic to this site entitled: “Deceptive Technology.” Unfortunately, the objective is neither to protect consumers nor predict the future (although some predictions may occur). Instead, the articles will explain why the technology does not live up to marketing or where engineering could have gone wrong.

In the case of uBeam, the founder does not have a background in STEM and continues to pursue her ideas even though science prohibits many of her dreams. In fact, she learned everything that she knows about uBeam’s technology on the Internet, which she admits in this TED talk:

Even if you ignore the adverse effects of ultra-sonic noise on the human body, you cannot ignore that an ulta-sonic wave will not pass through a human body.  Enough about uBeam, the realities of their wireless charging technology are well documented.

Disclaimer: It is still important for investors to consider these businesses. You never know when Tesla will invent a LiPo battery with better energy density than diesel fuel, but that does not preclude due diligence. It does not mean that you should buy a Tesla or that you wait on buying a new phone until there are uBeam transmitters in the cafeteria.

Energy density of common fuels and power sources.
Energy density of common fuels and power sources.

Hillbilly Helping Hands

Have you ever been stuck without your helping hands? Perhaps, like me, you were flying your quadrotor at an empty park only to have it break during its first flight of the day. I thought that it was time for the long drive home because I did not have my helping hands or a friendly neighbor.

What I did have was a bag of pretzels. That bag of pretzels happened to have a magnetic chip clip attached to it. Seconds later, the snapped part was hanging off the tailgate of my truck while a glued it back together. The Hillbilly Helping Hands were born.

For this build you will need:

  1. A chip clip with a magnet
  2. Spare rubber (optional protection for circuit boards)
  3. An inverted cast iron pot, a tailgate of a steel truck, or a steel hood

Warning: This will not work on non-magnetic or aluminum bodied vehicles such as the new Ford F150!

HillbillyClamp

 

It’s a quadrotor. Not a quadcopter & certainly not a drone!

Unmanned aerial systems (UAS) have been called a lot of names. The term drone,

noun :  an unmanned aircraft or ship guided by remote control or onboard computers via Merriam-Webster,

is linguistically correct, but the term has negative connotations that insinuate drone warfare. In a society where UAS are constantly accused of spying (often baseless accusations), I do not recommend calling your UAS a drone. No positive attention will ever surround drone activities.

Furthermore, the term quadcopter is argued to be linguistically incorrect. Mahony, Kumar and Corke (2012, paywalled) point out that:

The word helicopter is derived from the Greek words for spiral (screw) and wing. From a linguistic perspective, since the prefix quad is Latin, the term quadrotor is more correct than quadcopter and more common than tetracopter; hence, we use the term quadrotor throughout.

They argue that quad & rotor derive from Latin and tetra & copter derive from Greek. Therefore, they choose between the terms quadrotor and tetracopter. I would further rule out tetracopter because “four wings” makes less sense than “four rotors”.

This Week in Quads (a.k.a Know How…) Clips

Continue reading This Week in Quads (a.k.a Know How…) Clips

TWiT.tv plug

The TWiT network is a frequently overlooked gem in the new media world. Millennials are often too young to know about The Screen Savers, and those of us that are old enough often recall the television show instead of the forums. Although the television show was mediocre, the community building that it triggered in the forums was a milestone in Internet history. Members of the staff have gone on to shape the Internet that we use today. TWiT and Revision3 are two of the few successful streaming video channels. Kevin Rose moved on to create the first version of Digg.com, and he should be credited with the invention of the “like” button. Until Digg.com, all that we could do was +1 a post in an Internet forum. I am not a fan of TWiT‘s flagship entertainment show, This Week in Tech, but some the shows really geek out (Security Now and Ham Nation) while others are very informative (Home Theater Geeks, This Week in Computer Hardware, Windows Weekly and This Week in Law).

Tweet-a-Pot: Twitter enabled coffee pot (now with video)

This twitter enabled coffee pot has been on Instructables for a few months.  A video, which was added three days ago, really sells the idea.  Of course, most coffee pots already have time-based automatic-start, and nobody that I know has ever used it.  The implementation is very simple.  You only need a coffee pot, an Arduino, and an actuated switch to control AC voltage to the pot.  Will Keurig start marketing machines with a serial port interface in order to compete? Continue reading Tweet-a-Pot: Twitter enabled coffee pot (now with video)