I got some rotary encoders in the mail the other day so I could breadboard an autopilot panel I’ve been wanting to do. I’d like to include four seven segment displays to display heading, altitude, vertical speed, and speed (FLC). I haven’t purchased the displays yet because I don’t know what to get. From what I hear the 7219s are what you want but those only seem to be mounted to eight digit displays which is way too big for what I need.
Here is what I figure
heading (3 digits)
altitude (4 or 5 digits)
vertical speed (4 digits)
flight level change (3 digits)
Where can I find some cheap smaller displays already populated with a chip?
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Check this video out. In the description there is a link to the website with the parts list. He mentions the 7-segment displays he used.
It looks like the one I posted in the amazon link. This would have to mean it’s possible to split one display into two since he only uses three of them to show four things. I’ve looked in mobiflight and I can’t quite figure out how that’s done, he seems to gloss over that part in the video.
It’s fairly common to combine 2 types of data on one 8 segment module. Hdg and Spd for instance can share one 7219. You can either use the outside digits and mount it in a box so the 2 middle digits are un-used but provide some natural separation of the digits or you can either remove the displays from the board and extend them to your own made 3 digit modules or just buy the Max7219 chip and make your own. LoungePilot do some nice 7 segment modules in different colours if you want something already done. Not sure how you combine the data to send to a single module in MF but in Air Manager it’s a simple string concatenation.
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I strongly recommend Mobiflight. It can be a bit of effort to get going with, but we have a Discord for support (and we are very friendly!)
So I went ahead and got these off amazon a while back. Amazon.com
I got two hooked up to my breadboard circuit to show hdg, alt, vs and flc as was suggested. It took quite a bit of messing with as I ran into many problems but I think I got it working half way decently now. As an afterthought I wanted to be able to control baro while keeping the space down on my panel design so I already got my panel handcut from lexan with room for a toggle switch. My idea was to use this switch to switch between alt and baro on the left display. Is this possible?
EDIT: I did a practice run with a rotary tool on a scrap piece of PC and I didn’t like the way the cuts came out so I decided it would be simpler and easier on the eyes if I was to not cutout rectangles for the displays but just mount the tubes behind the panel. After some searching on the internet I’ve found someone who suggested standoff/spacers and screws. Would this work? Brass Standoff Spacer Silver Screw Hex Male M3x8mm
M3 Steel Truss Head Machine Screw 3x10mm
