Automating RC Motor Efficiency Testing

Small brushless motors and LiPo batteries are one of the most impressive bits of technology popularized in recent years. Just a few years ago, RC aircraft were powered by either anemic brushed motors or gas. Quadcopters were rare. Now, with brushless motors, flying has never been easier, building electric longboards is simple, and electric bicycles are common.

Of course, if you’re going to make anything fly with a brushless motor, you’ll probably want to know the efficiency of your motor and prop setup. That’s the idea behind [Michal]’s Automated RC Motor Efficiency Tester, his entry to the 2016 Hackaday Prize.

[Michal]’s project is not a dynamometer, the device you should use if you’re measuring the torque or power of a motor. That’s not really what you want if you’re testing brushless motors and prop configurations, anyway; similarly sized props can have very different thrust profiles. Instead of building a dyno for a brushless motor, [Michal] is simply testing the thrust of a motor and prop combination.

The device is very similar to a device sold at Hobby King, and includes a motor mount, microcontroller and display, and a force sensor to graph the thrust generated by a motor and prop. Data can be saved to an SD card, and the device can be connected to a computer for automatic generation of pretty graphs.

Brushless motors are finding a lot of uses in everything from RC planes and quadcopters, to robotics and personal transportation devices. You usually don’t get much of a data sheet with these motors, so any device that can test these motors will be very useful.

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Cheap Air Pickup

If you work with surface mount components, you might want an air pickup tool (sometimes called air or vacuum tweezers). You can find inexpensive ones that use a bulb or spring mechanism (like a solder sucker). While these are cheap, they don’t work very well. [Natsfr] had one of these cheap tools and decided to add a proper pump to make it work like a much more expensive tool.

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Save a Couple Thousand Dollars with a DIY Remote Lighting System

When you don’t need the durability of a professional system, this DIY remote lighting system will do.

Pelican makes a great remote lighting system. Unfortunately, it’s the kind of great that comes with a “Request Quote” button instead of “Add to Cart”. It’s designed to be thrown in the back of a tank and guaranteed to work at the end of the day. [mep1811]’s system is not that system. It’s the store-in-a-Rubbermaid-tote and throw in the back of the family Honda kind of great, but it’s made from stuff you can buy anywhere.

The build is contained by a water resistant plastic box. Two sealed lead acids and a battery charger sit inside. The system is hooked together with simple car outlets — also known as the worst accidental electrical connector standard of all time. For the lights, [mep1811] simply made mounts for chinese LED spots and bought some inexpensive camera tripods. With a full charge, he says it runs for forty hours.

In the end it’s not a complicated hack, but its simplicity adds a certain amount of ruggedness, and it will definitely do the trick in a power outage.

Smartphone and IR Line Laser Measure Distance

Measuring the distance using lasers is a mainstay of self-driving vehicles and ambitious robotics projects. The fine folks at MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL) decided to tackle the problem in an innovative way. [Jason H. Gao] and [Li-Shiuan Peh] used an infra-red (IR) line laser and the camera on a smartphone. Their prototype cost only $49 since they used a smartphone that was on hand. The article reports good results using the device outdoors in direct sunlight which is often a challenge for inexpensive lidars.

The line laser creates a horizontal line that is reflected back to the camera on the phone. The vertical position of the laser on the camera image lets the phone calculate the distance by parallax. To bring out a faint laser reflection, the algorithm compares four images – two with the laser on and two with it off – and subtracts the background. Using a smartphone for this is ideal since it automatically adjusts for light level and can easily be upgraded to a newer phone with a better camera later.

This should be a cheap and easily replicable setup. If you make one of these, let us know. If you need something more refined, check out this post on interfacing the Neato vacuum cleaner’s XV-11a lidar with the Raspberry Pi.

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Facebook To Slurp Oculus Rift Users’ Every Move

The web is abuzz with the news that the Facebook-owned Oculus Rift has buried in its terms of service a clause allowing the social media giant access to the “physical movements and dimensions” of its users. This is likely to be used for the purposes of directing advertising to those users and most importantly for the advertisers, measuring the degree of interaction between user and advert. It’s a dream come true for the advertising business, instead of relying on eye-tracking or other engagement studies on limited subsets of users they can take these metrics from their entire user base and hone their offering on an even more targeted basis for peak interaction to maximize their revenue.

Hardly a surprise you might say, given that Facebook is no stranger to criticism on privacy matters. It does however represent a hitherto unseen level of intrusion into a user’s personal space, even to guess the nature of their activities from their movements, and this opens up fresh potential for nefarious uses of the data.

Fortunately for us there is a choice even if our community doesn’t circumvent the data-slurping powers of their headsets; a rash of other virtual reality products are in the offing at the moment from Samsung, HTC, and Sony among others, and of course there is Google’s budget offering. Sadly though it is likely that privacy concerns will not touch the non-tech-savvy end-user, so competition alone will not stop the relentless desire from big business to get this close to you. Instead vigilance is the key, to spot such attempts when they make their way into the small print, and to shine a light on them even when the organisations in question would prefer that they remained incognito.

Oculus Rift development kit 2 image: By Ats Kurvet – Own work, CC BY-SA 4.0, via Wikimedia Commons.

My Most Obsolete Skill: Delta-Gun Convergence

In a lifetime of working with electronics we see a lot of technologies arrive, become mighty, then disappear as though they had never been. The germanium transistor for instance, thermionic valves (“tubes”), helical-scan video tape, or the CRT display. Along the way we pick up a trove of general knowledge and special skills associated with working on the devices, which become redundant once the world has moved on, and are suitable only reminiscing about times gone by.

When I think about my now-redundant special skills, there is one that comes to the fore through both the complexity and skill required, and its complete irrelevance today. I’m talking about convergence of the delta-gun shadow mask colour CRTs that were the height of television technology until the 1970s, and which were still readily available for tinkering purposes by a teenager in the 1980s.
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Hackaday Belgrade Talks will Live Stream Saturday

We have an amazing line-up of talks for Hackaday | Belgrade, Saturday April 9, in Belgrade, Serbia. The talks have been sold out for weeks. You can still get a ticket to the night’s concerts if you’re in the area. Either way, the big news this morning is that we will stream all of the talks live!

Live-stream links will be posted on the conference page as soon as we get them. You should also join the chat over on the Hackaday | Belgrade project page. Just click the “request to join this project” button in the upper right. Do that right now.

There are a ton of great speakers, check the poster below. I’m excited to hear Mike Harrison (mikeselectricstuff) speak about his journey down the rabbit hole of video projection tech, Phoenix Perry’s talk on Forward Futures, Voja Anotic’s talk about the hardware badge, Peter Philip’s talk about reinventing VHDL, and pretty much all of the rest too! From the Hackaday crew you can watch Sophi Kravitz give a talk on her shutter glass project, Chris Gammell will be talking Top Down Electronics, and I will end the 8-versus-32 argument once and for all (yeah right!).

While you’re listening to the talks, why not try your hand at badge hacking. You don’t need any hardware, you can use the emulator to try out your hacked code right now your own computer. We’ll be sending out prizes for the best entries and there are only a handful so far.

You do not want to miss these talks! If you don’t believe me, check out the talks from SuperCon last November and you’ll be convinced — Hackaday conferences provide the best collection of hardware talks anywhere.

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