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Frankentransmitter Part 1 – Planning

Posted by Tom Benedict on 28/03/2015

If you haven’t seen a lot of kite aerial photos or posts from me recently it’s because I’ve been categorically spanked the last several times I’ve gone out. If it’s not weather, it’s my gear. If it’s not my gear, it’s my batteries. If it’s not the batteries, it’s just life being a pain in the rear. It’s depressing, so I haven’t been writing about it.

Some time back I decided I wanted to rebuild all of my KAP gear from scratch, but I never got around to it. A couple of things have brought this to the fore on my list of projects. The main one is this recent history of blown KAP sessions. But a second and much more motivating reason is some phenomenal work by Dave Wheeler, a fellow KAPer. Dave built a really beautiful controller he described in the KAP Forum and documented on his project’s Github site. The core of Dave’s transmitter is an Arduino and the RF board out of a HobbyKing 6-channel transmitter – the same transmitter I’ve done KAP with for years. Dave’s transmitter is honestly more than I need for my style of KAP, but now I have no excuses left. Time to design and build the thing.

Before launching into my plans for the new KAP gear, here are all the issues I plan to fix:

Ease of Use – My gear isn’t easy to use. My ground unit consists of an RC transmitter and a wireless video screen. To use them I have to attach them together, then stick a cloverleaf antenna on the video receiver. To pack up at the end of the day I have to reverse the process. I go through a similar process on my KAP rig: attach legs, attach a feedline to the video transmitter, then attach the antenna to the feedline, etc. There are so many steps, it’s easy for something to go wrong. I want to be able to pull an already assembled KAP rig out of my bag, stick a camera on it, pull out my ground unit, and fly. No screws, no plugs, no antennas to install, no nothing. Just pull it out and play.

Flexibility – I have several KAP cameras: Canon T2i, Canon A650IS, Canon A2200 (x2), and a Gopro. Depending on the wind, the subject, my mood, or what have you, I want to be able to fly any one of these. In the case of the A2200 cameras I want to be able to fly both at the same time and do four-color photography. Right now I have to swap tilt brackets when I change from one set of cameras to another. I want to have one tilt bracket that’ll take the camera of my choice without swapping or modification, even if it looks like Swiss cheese.

No Dangly Wires – One of the features the brushless gimbal designers incorporated a while back is either hollow cored motors so wires can pass through each axis, or slip rings so the signals are passed through without wires to twist. With the exception of the shutter cable and video cable, there’s no reason to have any exposed wires on a KAP rig. I’d like to have jacks on the bottom rear edge of the tilt frame so that all camera cabling terminates right there on the tilt frame and doesn’t have to pass from one moving part of the rig to another one. I want to make custom cables for each camera so they’re as short and stout as possible.

Suspension Independent – My current rig has this already, but it’s a feature I want to bring over to the new rig. I want to be able to use a Picavet, a pendulum, or whatever suspension I want without having to rebuild the top end of the rig. I like the system I already developed, so I’ll adapt that to the new rig with few, if any, modifications.

High Badass Quotient – This is a personal thing. I want my gear to look like it was made that way on purpose. My CNC mill is back up and running, including the rotary stage. I’d like to use it for most or all of the parts for the new KAP gear. We’ve been testing some new surface treatments at work, and one stands out for home shop work: Cerakote. It’s a ceramic coating that can be applied in the home shop. The coatings are amazingly durable, really good looking, and stand up to wear and tear better than any paint I’ve ever used. They’re about as durable as good anodizing. Every bit on my rig will be covered in Cerakote. I want Hasselblad to be envious by the time I’m done.

What I want, in the end, is a much smaller, completely self-contained ground unit I can just pull out of my bag, turn on, and use. I want a KAP rig I can pull out of my bag ready to run with no chance of a popped wire, broken connector, missing antenna, etc. I don’t care if I take on another 100g in the process so long as it’s flight ready right out of the bag. I want my KAP bag to come down to a winder, a rig, a ground unit, and the kites of my choice. And everything should just work.

After all, isn’t that what we expect out of every other piece of camera gear we own? That’s what I want for KAP.

The design phase is next.

– Tom

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