Laser Labs includes reference samples with every tint meter so that the user can quickly tell if their meter is in spec. Every single test sample is measured by a spectrophotometer that has been calibrated with NIST-traceable light transmittance reference standards.
The old method of accomplishing this involved manually reading the spectrophotometer, typing it into a program, and pressing the print button. Since we were aiming to vastly increase our sales volume with new products, we needed a faster solution that was immune to fat-fingering in wrong numbers.
Luckily the spectrophotometer has a “Print” button that dumps its current measurement value out through a serial port. A USB-Serial module was used to connect the PC to the spectrophotometer. The Visual Basic program opens a serial port, and listens for incoming data. The “Print” button is not debounced, and the data dump is raw data with no headers or footers, so the Visual Basic program captures a stream of ASCII characters, scans for the number format (xx.x), and injects it into the label generation code along with the date. The label printer is a Zebra, so it uses a proprietary formatting language called “ZPL” (zebra programming language). The static portion of the label is saved as a series of strings, and the parts that vary (transmittance reading, date, serial number) are concatenated into some other strings. Its kind of chunky, but it gets the job done…
The end product is a small application that can automatically generate labels by hitting the print button on the spectrophotometer, in varying batch sizes (in case you want multiples of the same label with incrementing serial numbers), with the option to manually set the reading and date for calibration and testing purposes.
Please don’t call it a drone, it can’t do anything by itself.
After watching this video and a bunch of Flite Test videos, I decided that multicopters were cool and that I really wanted one.
Being new to RC aircraft, I started small with a Hubsan x4 so that if I was a terrible pilot or just didn’t like the hobby I wouldn’t be breaking the bank on a toy. I turned out to be terrible at flying the thing but it was wicked fun. Within a few weeks two of my friends had bought Hubsan X4’s for themselves, and another bought a knockoff DJI Phantom. The rest of the fall was spent flying around the field outside my apartment building and crashing into fences, walls, the ground, and each other. The X4 is surprisingly robust, surviving full speed crashes into brick walls (with a tailwind!) and tangling with the 10” props of my buddy’s fake Phantom without so much as a broken propeller. The little Hubsan turned out to be a great starter because spare batteries and propellers are dirt cheap, and because I could fly it indoors easily. The latter was important because fall turned to winter, and standing outside in Vermont without gloves on for extended periods of time isn’t exactly a pleasurable experience.
By mid-December, I was still having tons of fun flying the Hubsan and I had gotten good enough to fly confidently and consistently so I started looking into larger multirotor aircraft with first person viewing (FPV) capability. I picked a ready-to-fly 250 class quadrotor from myrcmart.com because it seemed like a good balance between size and maneuverability. Even though MyRCMart seems sketchy, and is run by some dude in China with access to cheap parts, the transaction went smoothly for me. Plus they accept PayPal, so you have that layer of protection if something were to go wrong. I also considered building my own from assorted HobbyKing parts but is was just so much cheaper to buy the pre-built one directly, especially since it included a 7-channel RC transmitter. For FPV gear I bought the starter kit from HobbyKing just because I wasn’t ready to drop hundreds of dollars on legit goggles.
The only things I added to my 250-sized quadrotor were landing gear and LED strips to help with keeping orientation. It actually came from China with some carbon fiber clip-on landing legs, but they weren’t tall enough to touch the ground if I mounted the battery on the bottom of the frame. A few #10-24 bolts through pre-cut holes on the motor mount arms solved that problem for a while, but a few cycles of crashing and bending the bolts then bending them back to straight broke them clean off. One thing I highly recommend is getting a carrying case for all your gear. I got a protective case for my airframe, tools, batteries, spare parts, etc. and it makes travel and setup much easier.
So far I can only say that I’m very happy with my quadrotor from MyRCMart. The carbon fiber frame looks to be high quality, and the arms are thick enough to not instantly shatter when you have a hard crash. In fact, the first time I flew it, I crashed arm-first edge-on into a boulder and the only damage is a small patch of dented carbon. I haven’t experienced any delamination anywhere on the frame. The only other area of damage is on the much thinner top plate, and that’s because I crashed top-first into a metal post, shattering two small supports. The flight control board is mounted directly underneath the cracked sections, but its undamaged so that means the frame did its job and protected the critical electronics.
As of writing this (Late July, 2015) I still haven’t really flown using FPV gear. I tried once right when I got it and was still new at flying, which didn’t work well. My spotters would tell me that people were on the field, and I’d immediately chop the throttle because I was afraid of hitting them even though they were a few hundred feet away. I also recently tried in my backyard, but the combination of low hanging branches and a badminton net made that pretty difficult. Now that I’m a better pilot, I just need to find an empty field (of which there are plenty near me) and probably a spotter. We’ll see.
Update, Late February 2016:
I moved two months after I wrote the first chunk and haven’t gone flying once since then. Its still winter where I am so I probably won’t be flying for another few weeks. Unless I experiment with the FPV gear in my apartment… I live alone and have a reasonable amount of open space. what could possibly go wrong?
I was elected to the position of Vice President of the team for my junior year (2013-2014). Duties included assisting in managing team resources and being a point of contact with our sponsors in addition to redesigning the battery enclosures. Major changes included a more robust mounting system, improved side impact protection, and better electrical isolation. The batteries were held to a steel plate in the battery box by interfacing with the grooves in their insulation. The steel base plate was held to a plastic bar which was anchored to the bottom of the battery enclosure. The plastic bar had weld nuts embedded in it, which allowed for robust mechanical connections between the batteries and the enclosure, but maintained electrical isolation as is required by the Formula Hybrid Rules.
Holding the battery to the box
Battery packaging
Mounted on car
Mounting bar cross-section view
In addition to developing the packaging for the batteries, I was in charge of protecting them from a side impact. This involved designing and fabricating a steel cage around the battery boxes on the side of the frame.
We came in 2nd place for the second year in a row, and we were awarded the IEEE award for excellence in electrical vehicle engineering. All that separated us from first place was a single lap on the endurance course, where instead of taking it easy for at least the first lap, I put the pedal to the floor and browned out the battery management system (BMS), putting us out of contention. Oops.
My first major project with the team was during my sophomore year (2012-2013). I was tasked with developing a system to mount the batteries to the car and protect them from a side impact. Luckily, during my freshman year I was given the job of assembling the previous design which involved irregularly shaped aluminum walls and about 1000 pop rivets, so I had a good idea of what not to do. Instead of making a custom enclosure during my sophomore year, I opted to use off-the-shelf parts to make the enclosure easier to build and maintain.
Figure 1: CleanSpeed 1.0 proposed design
Figure 2: CleanSpeed 1.0 final design
I used a Stanley tool box as the shell of the enclosure because they are lightweight, waterproof, and inexpensive. I designed a steel skeleton to affix the battery cells to the inside of the enclosure and an exterior cage to protect the battery from a side impact. There were two features of this design that I knew would violate competition rules; the polyethylene box was readily flammable, and the enclosure had conductive penetrations. I fixed these issues before the competition by using an intumescent paint to shield the plastic box and by designing acrylic caps to electrically isolate the inside of the enclosure.
