Digital is fun! Test of Teensy, cheap LCD screen and X-Plane 10

Back to cockpit designing

Printer failure dragged me out of the main goal for few days but was worth it. Print precision improved drastically.

I had to rethink whole concept of the air speed indicator. Idea was to use stepper motor to move needle to correct angle. Stepper motors are great for precise movement but they have one massive disadvantage, stepper doesn't "know" its own position. Can only move by certain angle from whatever starting position was. To fight issue I came up with idea to add two buttons underneath main face. Holding one of the buttons would simply move needle left/right to allow user to calibrate the needle. Would work but....setting it up every time would be annoying.

New idea.
By looking at the 3d printer I noticed "home" position of the steppers is set by a physical switches on the shafts. I want to avoid physical switches. Using phototransistor QRD1114 could be perfect for the job then. Planning to use it to detect when needle is in 0 knots position.

Features

• Phototransistor Output
• No-Contact Surface Sensing
• Unfocused for Sensing Diffused Surfaces
• Compact Package
• Daylight Filter on sens

Description

The QRD1113 and QRD1114 reflective sensors consist of an infrared emitting diode and an NPN silicon phototransistor mounted side by side in a black plastic housing. The on-axis radiation of the emitter and the on-axis response of the detector are both perpendicular to the face of the QRD1113 and QRD1114. The phototransistor responds to radiation emitted from the diode only when a reflective object or surface is in the field of view of the detector. 

Full spec here: https://www.fairchildsemi.com/datasheets/QR/QRD1114.pdf

Ordered few of these, cant wait for a delivery!

Printer fixed and upgraded with a glass build plate. Difference is massive!
No more expensive Kapton tape, just a cheap glue stick. Back to the project post soon

3D Printer failure

Lesson learnt today. Always triple check your printer before next print. After many hours of printing some of the screws went loose, right, rear axle dropped, here is the outcome:

Looks like the only damage apart from scratched build plate is blocked up nozzle. Not bad!

Already ordered glass surface upgrade on ebay for £13.50. Its a glass sheet cut to size. 

Busy days, way to busy to even think about this project. Ive found some time to design next version of the air speed indicator. Bad luck, yesterday I've lost 4 hours of my work due a crash of Fusion 360 :/ Cant blame Autodesk, its still very early version of this software. As a software engineer I entirely understand that this can happen. So designed it again, here's the result. 3D printing tomorrow.

From 3d printing to working prototype

3D printer broke down Saturday so took some time to get it running again.
Printing front plate for air speed indicator. Its still very early design so not sharing update design yet.



This is how indicator looks like for now. Final thing will be of course black/dark gray. Also planning some sort of back light.

Is powered by 28BYJ-48 stepper motor.
Specification : http://robocraft.ru/files/datasheet/28BYJ-48.pdf
Have decided to use steppers instead of servo motors. Most servos only offering 180 degrees of movement so it was decision between making soft of gearbox or simply use little stepper. They are less than £4 with a driver board. Wow!

Managed to get a prototype working today after many hours of tweaking the code. There is massive issue with stepper motors. They move by number of steps, it takes time, so to update angle position you must estimate or calculate position by time every update. I will share full source code after fixing some timing issues and adding calibration system. At the moment system works in relation to starting position.

Designing Air Speed indicator

So yes, when I said I'm building flight simulator, I really meant I'm manufacturing as many parts as I can. I will share everything, files, ideas, photos etc.

First design piece is Air speed indicator plate. Size 60x60mm

Version 1 ready to 3d print file, download here:  https://drive.google.com/file/d/0B09HXtw9sUPJT3k4VVpzVWE5M0U/view?usp=sharing

Autodesk Fusion

I have used Autodesk Fusion to design and export this part. Is very intuitive piece of software allowing you to design 3d parts without any 3d modelling knowledge. There is a trial version of this software available for free. Enjoy

More info here: http://www.autodesk.co.uk/products/fusion-360/overview