Initially I will use two different sensors for obstacle avoidance. lidar for closer range 2D image of space (obscale avoidance, scanning ground before landing, maybe SLAM)

and laser rangefinder for long range 1D distance sensing (looking for high buildings, maintaining altitude precisely, maybe high speed obstacle avoidance)

I went with cheapo robopeak hobby lidar, which seems to work well, here is a git repo for the library (node and beaglebone) (I also considered a lightweight hokuyo lidar) and for laser range finder I'll go with something like SF02 from paralax

these might be used in combination with some simple IR or just cameras (need more CPU but could double as optical flow sensors) used to locate becaons for landing or grabbing things

Ideally, both sensors should have an unobstructed front view on pitch dimension, with aditional unobstructed jaw dimension for LIDAR. Both sensors need to be able to independantly rotate on pitch axis for compensation of the angle of the drone when flying, and for scanning up and down (going in through windows, looking down when landing, etc) maybe rangefinder should also rotate on jaw axis on some fast servos for looking around independant of the drone orientation. not sure yet.

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IR and ultrasound were also options, they are cheap but tricky and unreliable, (ultrasound behaves extra badly due to propeller noise on drones) These things can be compensated for, but laser rangefinding will always afaik give more accuracy and reliability at a price.

I've been hoping to write this for a while, its not a very exciting project so I've been working on this when I'm tired.

its a bit unusual, nodejs-blosxom, ~400 lines of coffescript. this is very much a work in progress, I'd advise you to use it as inspiration more then as a code you run. templates related to my own homepage are included in the repo. might move them laters.

features

• each post is a markdown file (maybe I should check out ORG mode files?)
• posts are in a git repo, so they can be written offline and synced with the web later
• I wanted something like google plus circles, with restricted tags for particular people
• implicit tagging by placement .md posts in folders
• explicit tagging/metadata for a particular post by adding a JSON line as a first line in a file
• tag filtering
• no javascript on the clientside
• rss for arbitrary tag combination

immediate todo

• full set operations on tags
• think about collapsing large posts when they are initially displayed..
• also, don't render ALL matching posts, do the next/prev button thing.
• saving of blog post metadata JSON back to files
• color private tags differently
• wiki (some way to link to other posts or tags (just extend the markdown?))

things to figure out

• something super light for image galleries, I want to rsync images.. might implement this myself. flickr doesn't suck anymore, might hook into flickr?
• I want to extend the markdown renderer in order to be able to include things like youtube videos or my own images/galleries
• social network publishing - ifttt.com - I'll just use the rss.

at some point

• implement tag equalities and implications, for example music is always audio but audio is not always music, audio is always sound though.
• posts that are related to geographical location + geo search/map display.. I'd use this to mark interesting places, track trip progress and such