Archive | January 2015

Virtual retinal display

Built a retinal projector last night just for fun (and because i was curious what kind of image quality could be achieved).

WARNING : DONT DO THIS UNLESS YOU KNOW WHAT YOU ARE DOING. SHINING LIGHT INTO YOUR EYES CAN BE SERIOUSLY DANGEROUS. DO YOUR RESEARCH BEFORE TRYING ANYTHING LIKE THIS.

Notes:
Works Well, Produces a crystal clear image straight into your eyeball. unfortunately it seems that the alignment of everything and positioning of the eye needs to be to accurate for any practical use. The plan was to come up with a setup allowing us to make some kind of FPV goggles with this however without a lot of work this will not be stable enough on your head to remain reliable. the focal point must pass through your iris so a few mm of movement will cause you to loose the picture.

How It Works:
Image is produced by the Pico Projector. it passes through a variable ND Filter made of 2 linear polarising lenses, passes through the glass, reflects off the concave internal side of the magnifier (for refocusing) before finally reflecting off the glass slide and into the users eye (placed above).

IMG_20150120_205652

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250 Quadcopter

after recently building my first 250 sized FPV quadcopter i decided it was time to add some FPV gear. As i was rebuilding, i might as well upgrade the frame and have a tidy at the same time. Results below.
12 - Side Finished

Before FPV and New Frame.
02 - HK250

Old Mess.
04 - Oh god the wires

New Parts : ZMR250 frame (Real Carbon Fiber), Cobra 2204 2300Kv motors, and other parts taken from the HK250
05 - New Parts

ESC’s stripped,
2mm bullet connectors removed,
motor cables braided,
motors connected and directions tested.
06 - Laying out parts

Power cables finalised,
ESC’s re heat-shrunk,
07 - Under fame complete

Naze, receiver, Fpv cam and video TX all placed and wired in.
10 - Big TIFU Moment

At this point I went for a full system power up test, the first since completing wireing ESC’s. At this point every single component is connected to the main battery connector for power.

The keen eyed amongst you will have noticed that the XT60 in this picture is wired backwards. I quickly realised this as I connected my 2200mAh nanotech. There was a huge spark and a lot of smoke. Suddenly that sinking feeling.

At this point I realised that there was a large possibility that I may have KILLED EVERYTHING. I quickly unplugged everything and reversed the connector. I then began plugging components in one by one to see what was left. I have never been so happy to hear my ESC’s arming. Same with Naze connecting to cleanflight, then video came back.

For some reason it seams that the gods took pity on me and remarkably everything survived. I don’t know how but im not complaining. Could easily have been a very expensive mistake and all the previous time spent rebuilding would have been waited.

The lesson here, DOUBLE CHECK EVERYTHING, also TEST COMPONENTS ONE AT A TIME !

Finished Result:
11 - Front Finished

Im pleased with how this turned out. Far more manageable than before. Next job : Adding Led’s, however this can wait till another day.
01 - ZMR250 So Tidy

425 grams all in without battery as before. 50 grams lighter and a lot more power. To reduce weight more in future I may swap to a smaller FPV cam and reduce the red stand-off’s bringing the top plate down to just above the receiver. could also swap to nylon hardware but im not sure its necessary.
13 - Weight