Compass
This compass has a fixed pointer and the compass rotates.
28BYJ-48 We need to devise a method to fix this directional scale plate perpendicular to the stepping motor shaft.
The motor shaft has a diameter of 5.0 mm. Looking at the internal structure, this axis does not seem to be as hard as it looks. I avoided processing the shaft directly so as not to break it by applying excessive force.
In the center of the wood I made a disk with a hole of about 4.9 mm and I fitted it. I wish I had better materials.
Step Motor 28BYJ-48 is used to move the louver of the air conditioner, it is mass-produced and available at a low price. Like the parts of home appliances, the exterior is small and solid.
The same Step Motor is often used for meters sold overseas for flight simulators.
Since it makes one rotation in 4 seconds, it can not cope with fast movements, it is enough for meter production unless it is acrobatic flight.
360° rotation of the output shaft at 2048step (two-phase excitation) is important for Mobiflight's config settings.
Driving a stepping motor
A driver IC is used to handle a large current to drive the step motor.
This IC ULN2003 was attached to the step motor. Use 4 of the 7 transistor arrays. Since the current will be large, you should prepare a separate power supply without taking it from Arduino.
meter_size
The exterior of meters is made of vinyl chloride pipe with an outer diameter of 54 mm (inner diameter of 52 mm) and an aluminum plate of 1 mm. If it is made smaller than this, the motor will not fit.There are 4 holes so that it can be attached to the panel with 3mm screws.
After that, I removed the plastic of the front cover and changed the pointer to be displayed by hanging it with a 0.5mm brass wire.
If there is a cover on the surface of the meter, it will be difficult to see due to reflected light. The angle of the speedometer of the car is devised so that it is not difficult to see.
I used it on the compass because it was necessary to attach a pointer, but I removed the surface cover because it is easier to see if it is not possible. compass
My MobiFlight settings are as shown in the figure below. The north direction is zero on other meters. Move the pointer to his N position with the `Manual calibration` of the` ConfigWizard`, then press `Set Zero` to set it.
<--
