MobiFlight Community Support

Good day
I am busy to build a Boeing 737 MCP. What type of push buttons and toggle switches must I use. I will also use LED'S with the push buttons and toggle switches.

Hello Johan,

welcome to MobiFlight!

Your question cannot be answered in a few words. It would be nice to know which simulator you are using, which add-on.
When it comes to the MCP itself, a distinction is made between two devices: Honeywell and Collins. Both are basically the same, but look a little different.
Honeywell type is easier to build because the LEDs are not housed in labeled housings. The Collins type uses so-called Korry switches, in which the LED is housed in the housing.
If you have a 3D printer, you can make the housings for these switches (actually, they are buttons) yourself, as they are relatively expensive in the relevant shops.
So much for optics.

If you want to create an MCP, which should only work as a 1st attempt, you can fall back on relatively simple means.

Parts list for the mechanics:

5 ON-OFF switches (2 x F / D, 1 x A / T ARM, 2 x A / P DISENGANGE) - no specific company
16 buttons (N1, SPEED, IAS / MACH C / O, LVL CHG, SPD INTV, VNAV, LNAV, VOR LOC, APP, ALT HLD, V / S, ALT INTV, 2 x CMD, 2 x CWS) - no specific ones company
6 encoders type 1: 1 (2 x COURSE, IAS / MACH, HEADING, ALTITUDE, VERT SPEED) - the affordable encoders from ALPS are sufficient here
1 Rotary Switch (combination HEADING / BANK ANGLE) - no specific company

For the displays you use the green circuit boards (from China) for the MAX7219. Here the displays are removable. Depending on whether you want to use 1 circuit board with 8 digits for each display, you need 6 fewer pieces if you combine them. The parts cost just under 2 euros each. - Recommended seller in China: Sensecore company

Then you need an Arduino MEGA 2560 R3. It doesn't have to be an original here, a Chinese clone is enough for about 10 euros / piece.

You should also take the time to read in the forum how others have done it. If you have any questions, you can ask them here in the forum. If things get complicated, we can also help you on Discord.

Thanks Stephan
It will be a Collins MCP. I do have a lot of rotaries and encoders switches but want to know if I must use momentary push buttons with LED connected. Will momentary push buttons work or do I have to use latching push buttons. I am using Arduino card with shield

Will a LED stay on when a momentary button is pushed, meaning activate for example heading select.

Hi Johan,

a momentary push button normaly is always non latching. These ones work like a toggle.
The LEDs are always independant from the buttons. These are working via offsets. Every LED in your virtual cockpit has an offset. You have to read out this offset via MF and if you have it connected in the right way it will light or not - like in the sim.

If you have i.e. a PMDG then the offsets are for outputs (from the sim). EventIDs are used as inputs (like switches, buttons, encoders etc). So you have to separate the switch for something in your cockpit and a correspondeting LED. Best example is the switch/LED with the parking brake - please see tutorial.

And yes, a LED will stay on with a momentary button is pushed if you have wired it correct like in the tutorial.

Hi

I think you mean Buttons with integrated LED..... Like this.... https://www.reichelt.de/kurzhubtaster-rf-15-35vac-dc-au-2-led-rt-rafi-200-011-p110846.html?&trstct=pos_1&nbc=1

Important for Homecockpits is.... the LED must be indipended.....
Mostly Latching switches ( non momentary) can be problematic cause CarHifi Switches work different..... Here the LED is not controlled by a own Input line..... Its just connected to the switching circuit. Mean it simply light if Switch is in ON position.
For Homecockpits the LED must show the status of the Sim..... Not the status of the switch !

Whatever..... If you build a Collins with Korry switches it´s recommend to use the housings.... You need 2 LED Parts ( 2 chambers) that work also indipended..... the Upper is the white Backlight of the Label ( e.g. the Characters "VNAV" ) the lower is mostly Green and must light the dashboard area that show if Function is ON or OFF.

So here mostly we use a ordinary 5 cent microbutton and a 3D Printed or CNC generated Box for it.

As I live in South Africa Korry switches is not an option and to import it will be too expensive. I have do with what I can get here.

I fly FSX default 737

Sorry I mean a Honeywell MCP not Collins

Korrys are possible if you have a 3D-printer. You only need to search via google for "korry switch 3d printer"

Don't have a 3D printer to expensive in SA. Will start my build and revert back. Just one question as I am new to arduino I only use a bread board for testing and it is not a permanent install with arduino.

For testing a breadboard is ok. For the final product you should solder your wiring.
Only with the MAX boards you should be carefully because the chips are extremly sensitive regarding the wiring.