Holiday update and gift exchange postmortem

Happy Hackerdays readers! Since the last update it's been busy with the first semester of school finishing up, finals and the holiday season quickly approaching. In that time I've made a better HackerTree, run a beta test of the Maker gift exchange, made the major purchase of an oscilloscope,  and received a box of goodies from Texas Instruments. First semester was a mess and I made a lot of mistakes along the way that will be a lot of work to get my grades up out of over the rest of my time at school. I've reactivated my TechShop membership and will be up there doing a lot of work until January 17th when it expires again. Full details on the updates and a little teaser of the stabilization system progress after the break.

Wishng you all a maker Christmas and a hacker new year!

Rocket active stabilization system debugging update

Debugging the system on a cheap logic analyzer clone (review coming up soon)

        Ever since I implemented the new control code this system has been plagued with a pair of bugs that frustrated me to no end which I have dubbed "Harlem Shake" and "Mr Freeze." The "Harlem Shake" bug occurs when the IMU outputs seemingly random YPR values suggesting that it is tumbling even when the sensor is kept perfectly still. "Mr Freeze" as the name suggests, is when the system locks up out of nowhere and refuses to respond unless reset which does not prevent the glitch manifesting. After mucking around with the code and a string of long nights with quite a bit of coffee trying to figure out what the heck was wrong with the system, I finally fixed the problem. The following is just inferences based on my limited knowledge at the moment, if anyone has a better theory I'd be glad to hear it. Reading the serial logs led me to believe that the freezing glitch was caused by a FIFO (First In First Out) overflow due to the appearance of that message in the terminal just before the system locked up. Initially, I had messed with the FIFO data speed configuration from 200Khz to 400Khz to no avail before inferring that the data was coming in at a much higher rate than it was being output, being a problem in library implementation. Using a logic analyzer had not showed anything anomalous in the I2C data bus which would have signaled a problem with either the wiring or packet structure. My assumption is that the transcoding of the data  internally was taking up too much processor power or was out of sync causing it to glitch thus causing the system to grind to a halt. This is a library-level issue that I'll be investigating and attempting to fix. Googling around proved library wonkiness to be the case and the fix was to increase the baudrate to the maximum of 115200. After applying this single line fix, the system ran for 10 hours straight without any bugs or freezing at all. I have no clue as to what causes the "Harlem Shake" glitch but it has not appeared since the freezing fix was applied so I'm not going to complain, though it has me curious as to what the core of the problem is.

Hackaday DC event recap

Giving a talk to the packed room

As some of you might have seen, I recently attended the Hackaday DC event and gave a talk on the rocket stabilization system while there in addition to explanations and demonstrations to quite a few people that came by my table. Surprisingly, the Amazon AWS crew that was there took quite an interest in my project and gave advice on code upgrades for the stabilization system, namely dynamic control movement ranges dependent on velocity.

A tour of Small Batch Assembly

Company logo on the orange walls

Recently I had met up with Bob Coggeshall at the inaugural National Maker Faire and he invited me to stop by the factory sometime in the future. I wasn't out in the general Reston area for a while until there was a conference over there. Sent him a tweet, and the following day drove over through the rather nice technology district.

Combination railgun/coilgun development platform (version .01 craptastic)

Coilgun with projectile

Way back in 8th grade summer and freshman year of high school I got bored and decided I wanted to make an electromagnetic accelerator so I went googling and did a ton of research. As I had zero budget I had to kludge together most of this from junk I had laying around. As a result of this, the efficiency and overall power are abysmal.

ICStation lootbag

Quite a big bag here!

Earlier this year I entered my active rocket stabilization system in the 2015 ICStation Arduino electronic design competition on a whim because there was a chance at winning some components and discounts. The following month, much to my surprise, I received an email informing me that I had been an Honorable Mention and won a $20 coupon for use in their store($40 minimum purchase required). After a bit of difficulty with the site (cannot use coupons on items that are already on sale, I tried to make a purchase during a site-wide sale) I placed my order, which arrived a week later using the free shipping option(which included a tracking number). I am extremely excited to get working on my next batch of projects using these modules.

Spring break TechShop progress

Near-final fin with correct blending

Over this recent spring break, I'd decided to forgo the archetypal partying of the Senior year and continue work on my projects. My primary objective was to redesign the fin so it could be used with the round metal servo horns for easier integration and sturdier mounting. The main issue I was having was the splines not printing due to the low resolution of the printer which meant the servos are unable to properly engage with the fin.