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Christopher Blay
Works at YouTube
Attended Utah State University
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Software Engineer
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  • YouTube
    Software Engineer, 2013 - present
  • Meosphere
    Software Engineer, 2009 - 2013
  • Project Mutual Telephone
    Network Engineer, 2007 - 2009
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=^_^=
Education
  • Utah State University
    Computer Science, 2008 - 2013
  • College of Southern Idaho
    Mechanical Engineering, 2006 - 2008
  • Twin Falls High School
    2002 - 2006
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Christopher Blay

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Nice! Very jealous!
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I went to Robosub again this year! I had a great time chatting with all the teams and it was nice to run into a lot of people from the old USU-still-goes-to-Robosub glory days.

Lots of good looking subs and there was big upset this year since both Cornell and University of Florida were having problems. Other things to note:
- 3D printing propeller blades is a big thing U of F was looking into. I was actually looking into it a bit on my own already so got some good tips.
- Submarines can separate after they dive, so long as all parts stay underwater, and do different tasks simultaneously. Cornell was looking into this but their mini-sub didn't attend this year.
- Maybe this was already really common but I only just noticed many teams using epoxy to do sealed cable joins. Just like a huge cylinder of it with the cables going in on the sides. Seems to work pretty well.
- There's a new less-expensive hardware supplier called Blue Robotics [0]. They have pretty decent thrusters for $100 and a lot of teams were using them. They're looking into doing pressure vessels, and other things as well!?

[0] https://bluerobotics.com
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Christopher Blay

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Guillemot Update

Yes that's right! I've started working on this thing again. Going at it from another direction...

Guillemot Core

I've forked the old Gilligan ROS nodes at http://code.google.com/p/usu-robosub/ into https://github.com/chris-blay/guillemot-core and I've been cleaning it up a bit and trying to get most everything working on the Raspberry Pi. Unfortunately, getting ROS to work properly on Raspberry Pi is basically a nightmare.

ROS

I've been a pretty strong defender of ROS in the past, and I think that it's definitely worth using on a pure x86 Ubuntu setup (i.e., Gilligan), but I'm getting to the point where I'm tired of fighting ROS just to build a motherboard temperature publisher on a Raspberry Pi... With all the trouble ROS has already given me, I've basically done nothing productive as far as software goes, and that's incredibly troubling.

So what is it that ROS actually does that I like so much?
∙ Pub/sub and request/response communication paradigms. Transparently using IPC or sockets as needed.
∙ Marshalling - not great - but Good Enough™.
∙ Registry of publishers, subscribers, and severs for discovery.
∙ Tools to save messages published to specific channels and inspect/replay them later.
∙ Node startup/monitoring stuff. I'm looking forward to getting rid of the hacky Bash scripts.

I'm thinking ØMQ for communication, MessagePack for marshalling, a custom discovery registry, a custom persistence/replay tool, and Supervisor for startup/monitoring. This isn't something I'm going to do lightly though. I'll prototype out a few things before going all in. And this means Catastrophic Change in Guillemot Core, rather than a smooth transition, but I think there's potential for a much better future so it's definitely worth the effort.

Guillemot Sensor

This is still on the way! I'm having trouble with using library dependencies in Android Studio but once I have that figured out I'll publish to GitHub and this will be another big thing to work on. I've been planning on using MessagePack over Android Open Accessory Bridge so using it in Guillemot Core means no translation between marshalling formats!

Contributors

If you've ever thought to yourself "Wow this looks cool I wish I could help out" then you're in luck! I'm making sure to do as much of my development in the open on GitHub as possible going forward. Useful contributions are more than welcome - open bugs or feature requests, edit wikis, send pull requests, whatever!
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Christopher Blay

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Hmm which flavor of Blue Moon should I have tonight? Just write a C program for it!
C++ shell · cpp.sh. online C++ compiler. about cpp.sh · C++ Shell, 2014.
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That's the problem with randomness...
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Oh My Heck: SF Pride is hella crazy!
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You have a LOT of people out there! Thanks for sharing.
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Autonomous Submarine Update

I just realized I do this about once a month. An interesting observation of my own inadvertent-behavior...

Name and "Logo"

I enlisted some help from +Jenna Jane to pick out a cool name for the submarine and we decided on Guillemot (gill-a-mot) which is a family of seabird that dives underwater for fish [1]. Ha ha and of course since I'm starting work on the companion Android app, I had to make an Android icon (a.k.a. procrastinate from actually coding) which I think turned out pretty alright - it's attached.

[1] https://en.wikipedia.org/wiki/Guillemot

Android Open Accessory Bridge (AOAB)

I've finished the sub-project I mentioned last time which facilitates communication between an Android device and any regular PC using Android Open Accessory Protocol [2] over USB. It's pretty rudimentary but does what I need: launch a companion app on the device when told to from the PC, and close the companion app on the device when told to from the PC. While the connection is open both the companion app and PC can send messages up to 2^16-1 bytes in length. You can find this sub-project at [3].

[2] http://source.android.com/accessories/protocol.html
[3] https://github.com/chris-blay/android-open-accessory-bridge

Guillemot Sensor

I've started working on the companion app which will run on the Nexus 4 and communicate with the Raspberry Pi using AOAB. So far I'm just learning about which sensors are available and what everything means - there's a lot to take in [4].

I've also been looking into how I want to marshal messages going over AOAB and right now am decided upon MessagePack [5]. Once I have sensor messages arriving on the RasPi using this format then I just need a simple ROS node there to receive them and re-publish the data as ROS messages. Later, additional messages for vision-related stuff will be really easy to add.

As a side note, I'm using Android Studio [7] for this app and it's a nice change from Eclipse. I especially liked adding MessagePack as a Gradle dependency and seeing everything Just Work(tm).

[4] https://developer.android.com/guide/topics/sensors/sensors_overview.html
[5] http://msgpack.org/
[7] https://developer.android.com/sdk/installing/studio.html

Acrylic Happenings

I've been able to plan out which shapes are needed inside the submarine to hold everything in place - even during barrel rolls. Basically there's a "bottom half" that the batteries and phone sit in and a "top half" that fits over the top of all that and provides a lot of flat space for electronics. I got the pieces needed for this internal framing and threw in the two end caps needed for the pressure vessel to plan out a big cut on the laser cutter in Mountain View.

Then later I got a chance to look at the laser cutter and it's not quite as large as I had wanted. It's large enough for each individual cut but not everything at once as I was planning. I've attached my initial layout but will probably need to use two boards now that I'm aware of this limitation.

Legal Situation

It has come to my attention that there are some tricky legal waters I'm wading in with respect to whether I or my employer own the results of all this work. I explicitly asked for ownership of AOAB and that was granted which is fine and dandy but it's just a sub-project.

I could try to create some separation of concerns and say the hardware side of things is owned by my employer - especially since I'm using work facilities for it - and then I could say the hardware design and software are all on my own time and owned by me and I want to open source them. I'm thinking that is just a big can of worms I don't want to deal with though.

I'm planning on making this whole thing an official 20% project signed off by my manager - under the assumption that while my contributions are owned by my employer everything is still open sourced. Pending that all this goes well I can then get a project "hub" setup somewhere with wikis to document things, message boards to have meaningful conversations with interested parties, and code hosting such that external contributions are super easy. Until then, I'll continue to keep everything on my desktop at home - incubating if you will.

Misc

The reed switches showed up... I haven't played with them at all yet but one of these days I'll get bored of Android coding and do that.

Figured out what kind of O-ring to get - it's a doozy - AS568-443 N70. Now the fun part is finding a vendor online that lets me buy less than 50 at a reasonable price. I'm thinking I only need three or so.

Those tri-state buffer ICs showed up! And then I learned about pull-up resistors [6] so... I'm not going to use them now. Ah well.

I've completely given up on 3D printing propellers... once I figure out which direction the motors like to spin I'll go looking online for some molded ones to buy.

[6] https://en.wikipedia.org/wiki/Pull-up_resistor
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All I have are top/front/right projections in AutoCad. Ha ha I used to use AutoCad a lot back in the day so that was easier to put together...
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Have him in circles
102 people
Andrea Manwaring's profile photo
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Aggie USU's profile photo
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Christopher Blay

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Delicious jägerschnitzel, spätzle, and German beers!
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Christopher Blay

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I ran Bay to Breakers[0] this year as Nyan Cat[1] and it was pretty great! I didn't run too hard - my knee has been getting mad at me when I do that - but still finished in 1:04:24 which comes out to ~5m22s per km. It'd be nice to get down below 1h next year!?

Anyhow I just wanted to give some context to these pictures I forgot about on my computer. Please excuse the poor quality, they're the "free" versions instead of the $40 versions... that's an entirely different story.

[0] https://wikipedia.org/wiki/Bay_to_Breakers
[1] http://nyan.covertbagel.com
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Christopher Blay

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I wonder why everyone outside is screaming and yelling? I guess SF either won or lost... At least the multitude of fireworks are making me think we won. 😺
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We were cheering for KC Royals!  Down to the last out, thought maybe we would win but SF did it again!
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Christopher Blay

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Guillemot Update

Meh still absolutely no progress but perhaps I will be inspired to resume work because:

RoboSub Update

I went to the 2014 RoboSub (semi-)finals and spent a ton of time just wandering around talking to teams about their subs! Quite a few brand new submarines and even a couple first-year teams in the finals. Finals start later today so be sure to check out the live stream at http://robosub.org/ if you have any interest in this kind of stuff.
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Christopher Blay

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Autonomous Submarine Update

Nothing to report really. Still blocked on working things out with my employer. Been putting it off is all.
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Me five minutes ago: "What? Why would #Idaho be trending... Oh, wow cool!"
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