news helicopter lap unit keypad - Page 1
Forum section: electronics / projects

author: ITman496
author_rank: Regular Contributor
timestamp: March 18, 2017, 04:38:00 am
content: I'm proud to have been involved in this project.I was contacted by a friend to make a SDI video switcher and Multiviewer unit controller. It had to be compact, thin, back-lit, visible in the day, dimmable for night, and control their specific equipment. Also, the keys had to have symbols on them that made sense. So here we go! Some design decisions might not make sense but let me assure you, I didn't want to do them. Mainly the direct wiring to the unit instead of a connector. UGH. Oh well.This is it all running in the cockpit!All wired in!Never did I think I'd get to make something bolted to something made by general dynamics!

author: tpowell1830
author_rank: Frequent Contributor
timestamp: March 18, 2017, 05:05:13 am
content: Wow cool setup. Looks neat too.That one grey wire snaking over to the pilot's side bugs the hell out of me though.

author: ITman496
author_rank: Regular Contributor
timestamp: March 18, 2017, 05:21:47 am
content: That wire normally plugs into an iPad that wasn't there yet! Still annoying though, you're right. At least I think thats the wire you're referring to?Also, check these videos out!

author: tpowell1830
author_rank: Frequent Contributor
timestamp: March 18, 2017, 05:34:03 am
content: Oh wow, had white out on the camera a few times from the snow. Was that part of Long Island and Brooklyn that you flew over? Cool shots, wish I could fly over NY in copter.

author: ITman496
author_rank: Regular Contributor
timestamp: March 18, 2017, 04:24:23 pm
content: Yeah, it was! we shot up the river past Manhattan and then down into those areas! I dont get to fly with them very often but its very fun when I can..

author: med6753
author_rank: Super Contributor
timestamp: March 18, 2017, 06:49:01 pm
content: I assume that's WNBC channel 4 NYC? Seems every news organization in NYC has their own chopper and always looking for a competitive edge. Between all those news choppers, the tourist choppers, police choppers, and the corporate choppers it is one crowded (and noisy) airspace. And there have been midair collisions.

author: ITman496
author_rank: Regular Contributor
timestamp: March 18, 2017, 09:06:32 pm
content: this new heli actually has a cool thing which tracks all the traffic and calls it out to you (distance/direction) if you get close. The old one didnt have that. We found out about it because the volume was set way too loud and it deafened us, ha.It also has a screen that plots out the locations of the other helicopters on a map.Also, you assume correctly!

author: MagicSmoker
author_rank: Super Contributor
timestamp: March 18, 2017, 10:10:45 pm
content: Is that membrane switch panel with the logo "aphelion" your doing, as well? If so, was it 3D printed? Designing/making custom enclosures is one of the biggest obstacles to me making more gadgets of questionable profitability.

author: ITman496
author_rank: Regular Contributor
timestamp: March 19, 2017, 02:57:13 am
content: that switch panel is actually the thing I made! And yes, it is 3d printed in two pieces and sanded to make it nice looking!Also, I wish it was membrane. its actually laser cut acrylic keys on top of microswitches.This is the cutaway model of the keypad unit:

author: electr_peter
author_rank: Unknown
timestamp: March 20, 2017, 08:19:59 pm
content: Quote from: ITman496 on March 19, 2017, 02:57:13 amLooks neat. Does each button have four micro switch array to hold it and provide spring tension? How does it feel to press?

author: ITman496
author_rank: Regular Contributor
timestamp: March 20, 2017, 08:25:39 pm
content: yes, the overall structure is 4 microswitches, arranged in a top-bottom-left-right edge holding sort of thing. The switches require a bit of force to trigger, which is on purpose, because of the high vibration environment of the helicopter, and the critically of not having "accidental" pressings of the key like the previous setup did. There is a diffused acrylic key (sanded on each side) to spread the light from the WS2812 led in the center of the switches, and then on top of that is some 2 layer black on clear reverse etch acrylic I got from inventables, to make a wear proof key etch.The switches do indeed provide spring tension to the key, and they feel pretty okay. There is a drawback where amount of force changes depending on where you press it (ie: if you press on an edge you only fight one switch, but if you press nearer to the center you fight either 2 or 4 of them) but you get used to it. I'd do it differently next time, likely either try to get an actual membrane switch made, or have a hinged setup that pivots downwards towards the front onto only one microswitch. I'd have to experiment again. This design does work, however. I'm open to also using ready made switches, but I couldn't find something thin enough (less then 3/8" thick) , RGBW backlit, with easily changed symbols on it, at the right size, and cost.I dont think you'd dislike pressing it. I didn't really have an issue with it once it was installed and mounted firm to something substantial.

author: electr_peter
author_rank: Unknown
timestamp: March 20, 2017, 08:43:05 pm
content: Quote from: ITman496 on March 20, 2017, 08:25:39 pmI guess spring tension and feel would be very reasonable, especially if mounted to a firm frame.Based on custom symbols and functionality, I presume that all buttons have short press function only (no extra functionality if button is held for a long time). I have had experience with portable items which required to press and hold a button to function. These were a metal dome type switches and required substantial force from a single finger to hold - finger got tired after few seconds and it felt like switch got stronger and "pushed you out" (a bit of design fail).

author: ITman496
author_rank: Regular Contributor
timestamp: March 20, 2017, 08:50:57 pm
content: that does sound really annoying.. And you are correct, the only function these switches have is to be tapped. A minimum key press time of 30ms is required, and after that, its just pointless to hold it for any longer. (three cycles of the shift registers that read the buttons, to make sure it's not a glitch, followed by a 250ms stand-down time to make sure bounce won't re-trigger anything)