DASL Wiki

This page is read only. You can view the source, but not change it. Ask your administrator if you think this is wrong.
====== Lesson #2 ======

In the second lesson of the DASL UAV Training Program, students will construct their own UAV from the instructions provided and the materials listed in the bill of materials on the home page. Students will perform every task from building the frame to soldering the electrical components. Students will then test their UAV for it's first flight.

**Note:** Before starting, it is expected that every student has an adequate knowledge of proper soldering technique. If students need to brush up on their soldering, Adafruit provides a concise and well put together guide at: [[https://learn.adafruit.com/adafruit-guide-excellent-soldering/tools|Adafruit Soldering Guide]].
----
===== Part 1: Installing Mission Planner =====
The software we will be using in conjunction with these lessons is called Mission Planner. Mission Planner is a freww open sources software for windows which can interact with the Pixhawk to set certain flight parameters, controls, tune the controller, set new flight modes, and more. Students will be using Mission Planner in the beginning to set up their quad copters and later on for programming auto pilot missions. It is necessary that each student have their own copy of Mission Planner ready to use.\\
\\
The latest version of the mission planner software can be found [[http://firmware.ardupilot.org/Tools/MissionPlanner/MissionPlanner-latest.msi | Here]]\\
\\
Run the .msi and go through the installation process. When installing the software, you may be met with a prompt saying Windows can not verify the publisher of the drivers. To Bypass this, just click "Install this driver software anyways."\\
----
===== Part 2: Loading the Firmware onto the Flight Controller =====

----
===== Part 3: Construction =====
{{ ::uav_materials.jpg?nolink&800 |}}
Necessary Materials:\\
1. Q450 V3 Kit\\
2. LDPower Motor, Propellor, and ESC Kit\\
3. 2200 mAh LiPO batteries\\
4. Pixhawk Kit\\
5. Futaba Transmitter\\
Not Pictures: zip ties, velcro, and double sided foam tape.\\
==== Step 1: Bottom of the Frame ====
The first step of construction is to fasten the bottom plate of the frame to the four arms. The pads for where the batterie cables will be soldered is the back of the UAV. We place the arms so that one color occupies the back, and one color occupies the front. This is because when flying, it is very important to know what the orientation of your UAV is. As you fly your vehicle farther and farther away, it can become difficult to know your orientation and so we use the colors as a reference point. In the picture below, the white arms are placed in front and the red arms placed in back. If you are taking these lessons in conjuction with other students, it is recommended that you all follow the same convention for ease of explanations in further lessons.
{{ :img_2299.jpg?nolink&600 |}}\\
\\
==== Step 2: Attaching the Battery Cables ====
The second step is to attach the cables for the battery connector to the bottom PCB plate of the frame. The cables that come with the Pixhawk do not natively attach to the frame and so we are going to have to do some wire stripping and soldering. In the picture on the left you can see the battery cables. Using strong wire cutters or otherwise, cut the wires as close to the yellow plug on the right and strip off the remaining heat shrink. The exposed wires must then be soldered to the pads on the frame as shown in the right picture. It is absolutely necessary to solder the red wire to the positive terminal and the black wire to the negative terminal.\\
{{::img_2300.jpg?nolink&450|}} {{::img_2266.jpg?nolink&450|}}\\
\\
==== Step 3: Attaching Motors and ESC's====
The next step of construction for your sUAS is to attach the motors to the arms. When attaching the motors, it is very important to check the threading on them. Some motor sets have different threading for the clockwise and counter clockwise rotations, others are universal. The motors purchased for this course **DO** have specific threading and thus students must be extra attentive when attaching the motors to the arms.\\
\\
When placing the motors on the arms, you must pay attention to which way the threading is going. For this configuration, our front left and back right propellers will spin clockwise, and our front right and back left will spin counter clockwise. We want the motors to spin in a way that will allow them to tighten if the propeller makes contact with anything, and so if you are looking at the frame from either the front or the back, the threading should rise inwards towards the center of the frame, as shown in the photos below.\\
\\
{{::img_0006.jpg?nolink&450|}}  {{:img_0005.jpg?nolink&450|}}\\
\\
The next goal is to attach the ESC's. The ESC's do not require as much attention. Any ESC can be attached to any motor and for now it does not matter which of ports you join to which wires on the motor. If the motor ends up spinning in the wrong direction later on, it can be easily fixed by switching any two of the leads between the ESC and the motor. After your ESC's are connected, you must solder the wires to the bottom plate of the frame. The same convention is used as for the battery leads; red to positive, and black to negative. An example of the soldered leads can be seen above in the picture for the battery wires. On the left hand side you can see the red wire from one ESC and on the right hands side you can see the black wire from another ESC. After they are soldered you shoud zip tie the ESC and it's wires to the top of the arm so that they do not interfere with the propellers.\\
\\
{{ :img_0004.jpg?nolink&450 |}}\\
==== Step 4: Mounting the Flight Controller and its Peripherals ====
The next step is to mount the flight controller and all of the necessary peripherals onto the frame. To do this, we will be using double-sided foam tape. First, grab your Pixhawk and place a square of foam tape at each corner. If the tape you are using is thin, it would be a good idea to use multiple layers. It is a god idea to use enough layers that there is some clearance between the Pixhawk and the bottom plate so that wires can be secured between the two. The Pixhawk should be oriented so that the white triangle is facing up and the point is facing forwards. It is possible to program the Pixhawk for different orientations in the software, but it will not be necessary for these lessons.\\
\\
The first peripheral to connect is the buzzer. The buzzer is used to make different sounds that will be used to alert the pilot when certain parameters have been hit. This buzzer is useful for things like knowing when the battery has only a little amount of juice left. The buzzer should be mounted on the right hand side, again with double-sided foam tape, and it's wired should be looped under the Pixhawk then plugged into the "Buzzer" port on top.\\
\\
On the left hand side we will be mounting the R/C receiver and the arming switch. Mount the receiver using double sided foam tape with the antennae facing outwards. To avoid the antennae getting caught in the propellers, secure them in the zip ties used to fasten the ESC's. The arming switch can be mounted next to the receiver by zip tying it using one of the slots on the plate. The wires for both of these can be looped under the Pixhawk, however only the arming switch has a port on the top. The receiver must be connected to the RC port on the back of the Pixhawk, with the brown ground wire connecting to the top pin.\\
\\
{{ ::pixhawk_and_peripherals.jpg?nolink&450 |}}\\
\\
Finally, the ESC's must be connected to the Pixhawk as well. It can be seen in Mission Planner what motor is to connect to which pin on the Pixhawk. For the X-Configuration we are using the front right motor should be Pin 1, the back left motor should be Pin 2, the front left motor should be Pin 3, and the back right motor should be Pin 4.\\
\\
{{ ::img_0015.jpg?450 |}}\\
==== Step 5: Finishing the Frame and Mounting the Battery ====
To finish constructing the frame for your sUAS you need to fasten the top plate to the arms using the provided screws. When placing the plat on top of the frame, place it so that the two horizontal slots are in the front and back of the plate, and the single horizontal slots are on the left and right. The purpose of this is for using the velcro strap to secure the battery. On the top plate you should cut and secure a strip of the coarse end of velcro. You can cut a soft strip of velcro and stick it to the bottom of each battery. Although this fastens it, it is not secure enough, and so you should loop a velcro strap through the horizontal slots to the front and back of the battery and tighten it to hold the battery securely. The battery should be oriented horizontally.\\
\\
{{ ::img_0016.jpg?450 |}}


=====Flight Safety Assessment=====
\\ At the conclusion of this lesson  students will be given the opportunity to take the first test on safety. This test is needed in order to advance in rank.