Flight Sim Hardware - DIY
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Mode Control Panel (MCP)
Introduction
The Mode Control Panel (MCP) on the Boeing 737 Next Generation (NG) is a crucial interface for pilots to interact with the aircraft’s autopilot system. Located on the glareshield, the MCP allows pilots to input and monitor various flight parameters.
Image courtesy of X-plane 11 Flight Simulator
Key Components and Functions:
Autopilot Engagement/Disengagement:
A/P CMD Buttons: The MCP has two Autopilot Command buttons (A and B) to engage the autopilot. These buttons are used to control which autopilot channel is active.
Disengage Bar: A disengage bar at the bottom allows pilots to quickly disconnect the autopilot if necessary.
Flight Director:
FD Switches: The Flight Director (FD) switches provide visual cues on the Primary Flight Display (PFD) for manual flying, indicating the optimal flight path.
Speed Control:
Speed Selector: Pilots can set the desired airspeed using the speed selector knob. The MCP can manage airspeed in different modes, such as IAS (Indicated Air Speed) and Mach.
N1 and Speed Buttons: These buttons allow for automatic thrust management, ensuring optimal performance during different phases of flight.
Heading and Navigation:
Heading Selector: The heading selector knob is used to set the desired heading. It can operate in HDG SEL (Heading Select) mode or be slaved to navigation waypoints in LNAV (Lateral Navigation) mode.
Bank Angle Selector: A small selector allows pilots to limit the bank angle during turns, ensuring smoother transitions.
Altitude Control:
Altitude Selector: This knob sets the target altitude. The MCP can control altitude changes in VNAV (Vertical Navigation) mode or through manual inputs.
Vertical Speed (V/S) Selector: Allows pilots to control the rate of climb or descent.
Approach and Landing:
APP Button: Engages the approach mode, allowing the autopilot to manage the aircraft's descent along the glide slope and localizer during an ILS (Instrument Landing System) approach.
LOC Button: Captures and follows the localizer signal for precise lateral guidance during the approach.
Operational Modes
LNAV (Lateral Navigation): Automates lateral flight path based on the flight plan.
VNAV (Vertical Navigation): Manages altitude and speed profiles according to the flight plan.
HDG SEL (Heading Select): Allows manual heading adjustments.
ALT HOLD (Altitude Hold): Maintains the selected altitude.
V/S (Vertical Speed): Controls rate of climb or descent.
The MCP is designed to enhance flight safety and efficiency by enabling precise control over the aircraft’s automated systems
DIY - Flight Sim MCP
This comprehensive guide will walk you through creating a functional MCP using two custom-designed PCBs and an Arduino MEGA microcontroller. Perfect for flight simulation enthusiasts, this MCP replicates the essential controls in the 737-800 aircraft, enhancing your simulation experience.
Project Overview
The microcontroller-based Project (MCP) is designed to provide hands-on experience in developing and implementing a complete electronic system using a microcontroller. The project aims to enhance understanding of microcontroller architecture, programming, interfacing, and real-world applications, utilizing the Mobiflight connector for programming.
In our DIY MCP (Mode Control Panel) project for the 737 NG, we will design and implement two separate PCBs (Printed Circuit Boards) to control the left and right halves of the panel. This approach ensures modularity, ease of troubleshooting, and efficient management of the various controls and indicators.
Key Components
Two Custom PCBs:
Left MCP PCB:
Captain CRS (Course): Rotary encoder.
IAS (Indicated Airspeed): Rotary encoder.
AT (Autothrottle) Switch: Toggle switch.
Heading: Rotary encoder.
N1 (Engine Thrust): Push button.
SPEED: Push button.
LVL CHG (Level Change): Push button.
Bank Angle: Rotary encoder.
Right MCP PCB:
ALT (Altitude): Rotary encoder.
Vertical Speed: Rotary encoder.
Autopilot CMD A and B: Push buttons.
CWS (Control Wheel Steering) A and B: Push buttons.
First Officer CRS: Rotary encoder.
3D Printed Face Plate:
Design and 3D print the front plate either as two pieces as shown here, or three pieces if you have a smaller 3D-printer.
The front plate will house all the controls and provide a professional-looking interface for the MCP.
Step-by-Step Guide
Designing the PCBs
Each PCB shield is designed to replicate the specific controls of the 737-800 MCP.
Assembling the PCBs
Soldering Components:
Solder all components onto their respective PCBs. Ensure each connection is secure to avoid loose or faulty connections.
Wiring:
Route all wiring from the PCBs to the Arduino MEGA. Use jumper wires and connectors to simplify connections and ensure reliable communication between the PCBs and the microcontroller.
Programming the Arduino MEGA
Arduino Code:
Develop or upload a pre-existing Arduino sketch to handle inputs from the MCP controls and interface with your flight simulation software. This code will translate physical inputs into digital signals understood by the simulator.
Testing:
Before final assembly, test each control to ensure proper functionality. Make necessary adjustments to the code or wiring as needed.
Creating the Face Plate
3D Printing:
Design and print the face plate using a 3D printer. Ensure it has appropriate cutouts for all MCP controls, providing easy access and a professional finish.
Mounting the PCBs:
Secure the PCBs behind the face plate. Align the components with the corresponding cutouts.
Final Assembly:
Assemble the MCP by mounting the face plate onto an enclosure or panel. Ensure all wiring is neatly routed and secured.
Final Thoughts
This DIY Mode Control Panel for the 737-800 is a rewarding project that brings a new level of realism to your flight simulator setup. By following this guide, you'll create a functional MCP that looks authentic and enhances your simulation experience. Happy building, and enjoy your flights!
Arduino MEGA Microcontroller:
Acts as the central brain for the MCP, receiving inputs from the PCBs and sending outputs to your flight simulator software.
