Design is the first phase in the digital manufacturing process. In this course, through a series of lectures and hands-on lessons, we’ll examine a designer’s approach to the design and manufacturing process—from concept to 3D model. We’ll start by applying design thinking to understand user needs, and then we’ll explore design criteria as we dive deeper into Autodesk® Fusion 360™ sketching, modeling, rendering, and documentation features.
Design Criteria: Component Selection | Part 4
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3D Model Creation with Autodesk Fusion 360
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From the lesson
Conceptual Design
This week covers the fundamentals of laying out multiple sketches for a complex part. With a design like a quadcopter, it is important to understand the artistic freedom and the mechanical constraints. Through concept sketches, we explore the shape and form in various 2D views. This allows us to understand physical volume constraints for components like a controller, batteries, and camera while playing with the overall shape.
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For this design criteria lesson,
we're going to carry on with part four of our component selection.
After completing this lesson,
you'll be able to compare video components
and options and make informed design decisions.
First, let's talk about the camera system parts that are spec'd out for this series.
For the camera, we're using a FatShark 700TVL CMOS camera,
it's capable of NTSC and PAL.
For video transmission from the quadcopter down to the ground,
we're using a SkyZone TS5823.
For the Monitor and receiver,
we have a 7-inch 1024x600 monitor that's made by Fieldview.
So first, let's talk about the camera,
the FatShark 700TVL CMOS camera,
this is a good system because it has a few things going for it.
The CMOS type camera is lightweight,
it has low power consumption and because of the technology is fairly inexpensive.
This specific unit has a few extra things going for it.
It has removable lenses so we can change the field of view.
And it also comes with a pan and tilt servo already built into it.
Now in our case we only need tilt,
so I've deconstructed a bit.
I've taken off the pan servo and we've modified it
slightly so that the servo is going to be held directly with our 3D print.
When we're looking at cameras,
there are a few things that we need to be concerned with.
First of which is the type of camera.
Now there is a CMOS and there's a CCD camera.
Generally, the CMOS cameras are going to be less expensive because of
the technology but they're also going to be lighter and have lower power consumption.
While a CCD type camera,
or really the chip that's on the camera,
is going to be more stable,
less receptive to interference in the lines,
but because of this,
it's actually going to be heavier,
it's going to use more power.
Because we're completely concerned with
power consumption and weight rather than the quality of the video,
this is why we went with a CMOS camera.
The 700TVL is actually the number of lines on the image.
The 700TVL is actually a fairly high number so we get
a really good high quality color image out of this camera.
For output, NTSC or PAL is selectable on
this specific camera so we can decide how we want to transmit the video.
For video transmission, we need to
take the camera signal and we need to send it back down to the ground.
To do that, we're using a SkyZone TS5823,
this is operating at 5.8 gigahertz and has 32 channels.
This also allows us to send both audio and video.
Now this has a few things going for it.
First of all, it's small and it's lightweight,
this is again important because it's our main focus to keep
the overall system as light as possible to increase flight time.
The specific unit running at 5.8 gigahertz will
give us about a mile of range with no obstructions.
So, if we're flying in an open field or
an open area where we don't have a lot of tree coverage or buildings,
we can get a pretty good range to get our video signal back to us one mile away.
This specific unit has a set of
DIP switches on the board that allows to change the channel.
So we're operating at 5.8 gigahertz but we
have up to 32 different channels that we can operate on.
And this specific unit also comes with
a cable that allows us to run it directly to a GoPro.
So again, this goes back to being able to configure our system.
If we want to run a GoPro camera,
we can plug the micro USB that comes directly with
this board and transmit both audio and video back down to the ground fairly easily.
The nice thing about running a GoPro is it's got
a self-contained SD card to store the video and it also has
an onboard battery so we don't have to wire the GoPro up to
the system with the exception of sending the video
back down to the ground with a live feed.
And lastly, we have the monitor and receiver.
Now the one we're using is a field view 777,
and this is a great option because it's already has a
5.8 gigahertz receiver with 32 channels on it,
it's a 7-inch 1024x600 color monitor and it also has audio capabilities.
It has video in and video out so we are able to send
the video out of this monitor and recorded on another device if needed.
The specific one is fairly high resolution,
it matches the 32 channels that we have on our transmitter,
it's 2.4 gigahertz protected.
And that means that the 2.4 gigahertz
frequency were operating at with our controller that
sends a signals to the quadcopter that tells it to go up or down, pitch left or right.
It's not going to affect the video quality at all because
this specific one is isolated from the 2.4 gigahertz frequency.
This monitor also has a built-in battery,
and with a charge, it can last up to two hours.
And again, it does have audio capabilities as well as a headphone jack on the side.
There are many different options that you have
when you're trying to view the video on screen.
Because we're building a similar type of quadcopter to
an FPV or first-person view quadcopter,
there are plenty of on-the-shelf different types of goggle systems where you can
get the 5.8 gigahertz signal directly to a set of goggles that you wear so that way you,
can see exactly what you see from the quadcopter when flying.
Now the reason I chose to go with a monitor rather than a goggle set up is because,
the monitor can be viewed by somebody else,
fairly easily because it is a seven inch monitor.
It also allows us to fly line of sight with
the pilot while somebody else is viewing the camera.
If you just have a set of goggles and a first person view setup,
then you're not going to be able to have anybody else
look at the monitor or send the video signal
out to another set of monitors to have more eyes looking at what we see on the ground.
So again, this is a great option, fully self-contained unit.
And if you search around online,
you can find various prices for these that range from about a $100 to 150.
So overall, the camera system parts,
let's talk about what we have.
We've a lightweight camera and a transmission module.
The SkyView TX module operates at 5.8 gigahertz,
it has 32 channels available.
We have a high resolution,
a 700TVL color output camera.
We can also swap out a GoPro camera and we can
transmit audio and video easily with the TX module that we chose.
We're using options that have low power consumption,
because our camera is a CMOS chipset.
It actually operates with lower power consumption than a higher quality CCD camera.
Our camera is currently running at about five volts,
while the transmission module is running between 7-24 volts.
So, there's a wide range of voltage that we can operate on,
but we need to provide at least seven volts to be able to transmit the video down.
The good news is that,
the battery set up we're using is 11.1 volts or 14.8 volts.
We're using a power distribution board so we can
automatically supply the voltage needed to both things.
We also have camera tilt included with the camera that we chose.
There are plenty of camera options on the market,
some automatically have the transmission modules built onto them, including antennas.
So, if you're looking to build your own system,
don't think that you have to go with the cameras that we chose.
If you want to use a fixed camera or if you want to build your own tilt setup,
you can buy individual servos,
you can buy specific cameras and transmitters,
and you can pick and choose which components you want.
You can very easily get away with using
a GoPro that you have because we're planning our builds that
we have enough capacity to lift a GoPro or additional equipment as needed.
So that might be a great way to get a first person view by
using a fixed GoPro without including the tilt module,
plug it directly into the transmission.
So now, let's talk a little bit about how we can get the camera to tilt.
There are two different pieces of equipment that we can choose.
One is a brushless gimbal motor and this is
very similar to what our propeller motors are going to be,
and the other is a servo.
Now, each of these have pros and cons and I just want to pinpoint a few things here.
The gimbal motors are heavy, and generally,
they're only seen on higher capacity quadcopter or multi-rotors.
They do offer smooth motion.
Because they are brushless,
they don't have notches or different areas where
we're dealing with the gear reduction system and a stepper motor.
They do, unfortunately, require additional parts.
Generally, when you deal with a brushless gimbal motor or multiple gimbal motors,
you will have its own controller.
Now the own controller will also have a similar type of ESC that we
see when we're driving the motors that have our propellers and provide our lift.
Keep in mind that if you decide to go with a gimbal set up on one or two axes,
you're going to be adding probably
an additional 200 grams in just the gimbal motors alone,
plus you will need an extra circuit board that can help control that.
However, with the servo motor,
we generally have a fairly light package.
We will get jerky motion because we do have a gear reduction inside of the servo,
but it does plug directly into the CC3D.
Now I do want to make an important note here,
gimbal motors are generally used for stabilization.
Now, you often see these on
two or three axes rigs when somebody is running a high quality camera,
whether it's a video or still camera,
to make sure that they isolate the motion of the quadcopter and keep the camera stable.
Now this is great if you're doing
a high-quality photography or you really need that stable camera image.
In our case, the weight is going to be more
important than the jerky motion of the camera tilting.
We are going to be using manual control of the servo,
so we don't really need to worry about
that smooth motion because we're going to be turning a dial
on the controller to look down or up as needed with our camera.
We can use automatic stabilization with our CC3D flight controller to control
a servo to automatically tilt the camera up and
down based on the angle that the quadcopters flying at.
So while we will get a little bit of jerky motion,
we can achieve the same type of thing that a typical gimbal setup will require.
However, we can do this without having additional equipment because we can send
a five-volt signal directly to the servo to
control it without having any additional boards,
IMUs which are inertial measurement units, or any ESCs.
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