This Howto will develop into a detailed project plan for building a C172P Instrument Panel. While not a step by step guide, it will include details on the prototyping, design and building of a panel. The project includes the following major activities:
Open Identified Tasks
Task Description |
Blocking Factors/Action Items/Progress |
Status
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Bench Power Supply
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- Blocked by Lack of suitable case
- Action: Visit Robinson's Hardware, check out aluminum sheet
- Blocked by: Lack of a Bending Brake
- Action: Make a Bending Brake
- Action: Bend Some Tin
- Test what load Resistor will turn on the power supply
- Drill Mounting Holes for Load Resistor
- Mount the power supply in the case
- Blocked by: No way to extract power from power supply without cutting wires
- Action Taken Ordered 24 Pin Socket from E-Bay
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Proceeding in part
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Task Description
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Blocking Factors/Progress
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Status
Description
The work product will match an actual C172P cockpit instrument panel as closely as possible given constraints of tool availability, time and money.
Versions:
- A set of rotary encoders and switches in an overlay for a regular monitor
- Expand the project to include items in the radio stack
- Replace the monitor with individual instruments
Design Alternatives
- Instruments
- Monitor Overlay
- Individual Instruments
- Multi-value inputs
- using potentiometers and ADC ports
- Using magnetic encoders with:
- AtMega driven pins
- SPI
- I2C
- Display of Numeric and Alphabetic data
- driven by Maxim Max7221 on an SPI interface
- driven directly by an AtMega processor
- Banks of switches and rotary encoders with a multiplexed parallel interface
- Raspberry Pi connected to one or more AtMega Processors via SPI or I2C
- Raspberry Pi connected to a 4 to 16 bit multiplexer to select SPI data
- Raspberry Pi responsible for interfacing raw data to flightgear property values
- Display of numeric and alphabetic data using 7 and 16 segment displays
- drive with AtMega chip and Transistors
- drive with Maxim Max7221CNG Integrated Circuit
- AtMega Processors with port expanders responsible for raw data
- AtMega Processors communicate with Raspberry Pi
- Telnet interface to Flightgear runs on Raspberry Pi
== Code Development Activities
Client to Flightgear protocol
=== Client to AtMega protocol
Pi Client
AtMega Client
Magnetic Encoders
- For Heading Adjusters on Instruments
- Replacement for Rotary Encoders
- Replacement for Potentiometers
Proof of Concept and Prototyping Activities
Client on PI
Communication with Flightgear using Telnet
- Change the value of a cockpit switch
- Read the value of a Com or Nav Radio's frequency
- Change a standby frequency
- Make a standby frequency the in use frequency
- Dim and brighten the instruments
- Move the throttle
- Move one of the control surfaces
SPI
- different speeds
- Error Detection and re-transmission
- Client to ATMega
- Client to Max7221
- Client to Port Expander
I2C
- different speeds
- Error Detection and re-transmission
- Client to ATMega
- Client to Port Expander
Client on AtMega
Communication
- I2c
- SPI
- Raw Data Protocol
Data Acquisition
- Switch
- Rotary Encoder
- Magnetic Encoder
- Potentiometer
Control Data
- Air Core
- Stepper Motor
- Lighting Level
Building
Hardware Choices
- AtMega Models
- Raspberry Pi III
- for 7 and 16 segment displays
- Max7221
- or 7 Segment Driver Transistors
- 4 to 16 Multiplexer
- Magnetic Encoder
- Rotary Encoder
- Slider Potentiometer:
- Power Supply: Bench Supply based on an ATX PC power supply
- Knobs
- Heading Adjusters
- Radio Stack Volume
- Radio Stack Frequency Select
- Radio Stack Buttons
- Rotary Switches
- Rocker Switches
- Toggle Switches
- Main Switches
- Magneto Switch
- Flaps Lever: Design the Mechanism to attach to a rotary switch
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