jmig
SOH-CM-2024
T-38 Blog
9/25/10
End Devices for I/O Cards
Real world pilots control aircraft functions with switches, potentiometers, encoders, etc. We virtual pilots can also control our virtual aircraft with switches, potentiometers, encoders and more…through the I/O card.
Remember the I/O card is nothing more than a middle man between us and the flight simulator. By twisting a knob, or moving a control we send information through the I/O card to our virtual airplane. In this entry we will look at some of these devices.
We can attach many different input devices to our I/O card and tailor the flight sim to our desires. Because I/O cards have Analog to Digital (A/D) circuits build into them they can often break down the 256 steps of resolution MSFS offers through the Game controller applet into many more. Some I/O cards provide over 4000 steps within the control movement. The homemade throttle, shown in the picture, illustrates what this means to you, the flight simmer. If your throttle has 4096 steps from 0 to 100% throttle, you have a much finer control of the throttle. View attachment 19847
The photo below shows some of the input devices which can be attached to I/O cards. You see both rotary and slide potentiometers. Slide pots are good for throttles, props, mixture and such. With pots you want to use as much of the device’s travel as possible. Most rotary pots only turn around 270 degrees.
The device that looks like a pot with the red wire is a Grey type encoder. This one has a built in on/off switch. A Grey encoder is actually a special kind of rotary switch. It counts the detents with each detent being an on/off point. So a Grey encoder can count the steps (detents). They also have the ability to tell which way you are turning the encoder. Encoders are often used in radio turning or selecting course, headings, and altitudes in an autopilot.
The larger silver pot looking device below the encoder is a Hall Sensor. Hall sensors use a rotating magnet to measure angular movement and convert the movement into a voltage change. They are much like potentiometers in operation. Hall sensors do not have contacting surfaces and so they do not wear out like pots. They are generally much more accurate than pots. Another advantage of a hall sensor is the ability, through software, to use only part of the travel range with the total resolution. What that last sentence means is this; let’s say you are using a hall sensor for brakes. Brakes have a very small range of motion, maybe 30 degrees. If you have the software to do it with your I/O device you can squeeze those 4096 steps above into the 30 degree movement. You can’t do with a pot. View attachment 19846
.
Switches
Switches come in two main types. There are momentary switches, which are normally off. A momentary or push-button switch is only on when pushed. As long as the switch stays pushed it stays on. As soon as it is released it turns off again. This type of switch sends a single pulse of voltage to the I/O card.
They are often used as toggles, meaning one push turns on and another turns off. The push buttons on your joy stick are momentary switches. A momentary switch can be programmed to repeat itself. A good example of this is the trigger on your joystick. So long as you hold it closed, the I/O card will send repeated pulses to the flight simulator program.
The other type of switch often used is called a toggle switch but it really is an on/off switch. This is like a light switch. You flip it on and then you flip it off. These types of switches can be found in different formats or packages. The picture below shows several types of switches.
View attachment 19845
If you go back to the blog entry with the cockpit pictures, you will see many of these switches and others being used in the cockpit.
In our next entry we will start actually building a simple panel which will do some of the common functions within FS9, FSX or X-Plane. We will control the landing gear, flaps, lights and more using our panel.
9/25/10
End Devices for I/O Cards
Real world pilots control aircraft functions with switches, potentiometers, encoders, etc. We virtual pilots can also control our virtual aircraft with switches, potentiometers, encoders and more…through the I/O card.
Remember the I/O card is nothing more than a middle man between us and the flight simulator. By twisting a knob, or moving a control we send information through the I/O card to our virtual airplane. In this entry we will look at some of these devices.
We can attach many different input devices to our I/O card and tailor the flight sim to our desires. Because I/O cards have Analog to Digital (A/D) circuits build into them they can often break down the 256 steps of resolution MSFS offers through the Game controller applet into many more. Some I/O cards provide over 4000 steps within the control movement. The homemade throttle, shown in the picture, illustrates what this means to you, the flight simmer. If your throttle has 4096 steps from 0 to 100% throttle, you have a much finer control of the throttle. View attachment 19847
The photo below shows some of the input devices which can be attached to I/O cards. You see both rotary and slide potentiometers. Slide pots are good for throttles, props, mixture and such. With pots you want to use as much of the device’s travel as possible. Most rotary pots only turn around 270 degrees.
The device that looks like a pot with the red wire is a Grey type encoder. This one has a built in on/off switch. A Grey encoder is actually a special kind of rotary switch. It counts the detents with each detent being an on/off point. So a Grey encoder can count the steps (detents). They also have the ability to tell which way you are turning the encoder. Encoders are often used in radio turning or selecting course, headings, and altitudes in an autopilot.
The larger silver pot looking device below the encoder is a Hall Sensor. Hall sensors use a rotating magnet to measure angular movement and convert the movement into a voltage change. They are much like potentiometers in operation. Hall sensors do not have contacting surfaces and so they do not wear out like pots. They are generally much more accurate than pots. Another advantage of a hall sensor is the ability, through software, to use only part of the travel range with the total resolution. What that last sentence means is this; let’s say you are using a hall sensor for brakes. Brakes have a very small range of motion, maybe 30 degrees. If you have the software to do it with your I/O device you can squeeze those 4096 steps above into the 30 degree movement. You can’t do with a pot. View attachment 19846
.
Switches
Switches come in two main types. There are momentary switches, which are normally off. A momentary or push-button switch is only on when pushed. As long as the switch stays pushed it stays on. As soon as it is released it turns off again. This type of switch sends a single pulse of voltage to the I/O card.
They are often used as toggles, meaning one push turns on and another turns off. The push buttons on your joy stick are momentary switches. A momentary switch can be programmed to repeat itself. A good example of this is the trigger on your joystick. So long as you hold it closed, the I/O card will send repeated pulses to the flight simulator program.
The other type of switch often used is called a toggle switch but it really is an on/off switch. This is like a light switch. You flip it on and then you flip it off. These types of switches can be found in different formats or packages. The picture below shows several types of switches.
View attachment 19845
If you go back to the blog entry with the cockpit pictures, you will see many of these switches and others being used in the cockpit.
In our next entry we will start actually building a simple panel which will do some of the common functions within FS9, FSX or X-Plane. We will control the landing gear, flaps, lights and more using our panel.