Micro 105 FPV Quadcopter - 3D Printed

I've been flying 250 sized FPV (first person view) quadcopters for just over a year now. For those who aren't familiar with FPV, you outfit a camera to the front of your quadcopter and transmit the video to a pair or goggles or a monitor. You then get to pilot the quadcopter from the perspective of the aircraft. It is so much fun and lets you fly in ways that would be impossible line of site.

I wanted to build a micro FPV quadcopter that I could fly around my house and in areas where my larger copters are too big. I have a 3D printer so I was hoping that I could find a 3D printed frame that I could use. Unfortunately, I couldn't find any 3D printed frames that were exactly what I wanted. I decided to design my own! My goals were to keep it crash resistant, light weight and offer good protection for onboard gear.

I'm going to walk you through the steps to building your very own micro FPV quadcopter. You will have a blast flying it and will have the pride of having built it yourself!

Basic Parts

• Frame: Micro 105 FPV Quadcopter.
• Flight Controller: Micro Scisky
• Motors: Hubsan X4 H107c 8.5mm Motors
• Battery: 380mAh Hubsan or 500mAh Hubsan
• Battery Charger: 6 In 1 Charger. You can also find 6 packs of the 380mAh and 500mAh batteries listed above that come with this charger.
• Props: Ladybird props.
• Battery Pigtail: I cut one of the leads off of a charging adapter.
• Nylon Hardware: M3 nylon nuts and 20mm M3 nylon machine screws.
• Printable Standoff And Clip: As an alternative to using nylon hardware, navyblueboss made a very nice pin and clip set. I have not yet printed a set of these but they look great.

Radio Options

The Micro Scisky requires a DSM2 compatible receiver. Of course, you will only need one radio but here are some options.

• Taranis Plus + OrangeRX DSMX/DSM2 Module
• Spektrum DX6i
• Spektrum DX5e
• FsFly T-Six

The parts listed above are enough to get you up in the air. If this is your first quadcopter build, I would suggest stopping here and getting comfortable with flying before you install FPV gear.

FPV Gear (Optional)

• Camera: 170 Degree Wide Angle Camera
• Video Transmitter: FX758-2 5.8G 200mW vTX
• Voltage Regulator: Pololu 5v step-up - NOTE: In the attached image, I was not using a 5v regulator and was drawing power for the FPV gear straight from the flight controller. This is not recomended and can fry the voltage regulator on the Scisky.
• Antenna: 20-22awg solid copper wire.

Video Options (Optional)

There are many options for viewing the FPV feed but here are a few.

• Eachine EV800 Goggles - These are inexpensive goggles that can double as a standalone screen. These would make a good pair of starter goggles.
• Fatshark Dominator V3 Goggles + Receiver Module

Other Stuff You'll Need

• Soldering Iron
• Solder
• Basic Soldering Skills
• Zip Tie
• Double Sided Tape
• Wire Cutters
• Hot Glue Gun
• Hot Glue Stick
• Rubber Band

Head to Thingiverse and download the frame. I recommend using the V3 bottom. It is the strongest of the bunch. Pick a top that suits your flying style. There are options for camera with up-tilt, down-tilt, and straight ahead. There is also a top without a camera mount.

Be sure to follow the printing instructions on the Thingiverse page, these settings will yield the strongest print. PLA can be used but ABS will give you more crash resistance. In the photo, I printed the top in PLA and the bottom in ABS.

If you don't have a 3D printer, use the 3D Hubs button to get one printed.

Attach Flight Controller

Use some double sided tape to attach the Scisky to the frame. Make sure that your USB cable can access the USB port with the Scisky attached. You can add another layer of double sided tape if it is hard to access the connector. I used a hobby knife to shave some of the plastic from the connector of my USB cable to make it easier to plug in.

I like to add a zip tie around the Scisky and through the bottom of the frame to help hold it in place.

Install Motors

Insert the motors into the frame. If you find the motors hard to install, you can use a flat head screw driver to open the gap in the motor mount to help you slide them in. You want the motors to be snug. If the motors feel loose in their mount, use a little bit of electrical tape around the base of the motor to help keep them tight. Be careful that you allow the motor wires to pass through the slot when pushing the motors into the mounts.

The motors wire color corresponds to the rotation of the motors. I have annotated the photo with the correct motor rotation for each position along with the corresponding wire colors.

Next, carefully solder the wires to the motor solder pad. The color of the wires indicate polarity.

• Red +
• Blue -
• White +
• Black -

The solder pads for the motor wires are very small and can be a challenge to solder. Double check that you didn't bridge any of the solder pads.

Install Battery Pigtail

Cut a lead off of the charging cable. You will want to experiment with the correct length. The pigtail should reach the battery's connector but should stay out of the way of the props. I like to use a rubber band on the top to both hold the battery and help keep the battery lead out of the props. Once you have found the size you like, solder on the battery pigtail, connecting black to GND and red to VIN.

Installing Cleanflight Configurator

Cleanflight is an open source firmware for flight controllers. The Micro Scisky runs Cleanflight and needs to be configured. There is a lot of depth to configuring Cleanflight but I am going to go over the basics to get you flying. There is plenty more to learn if you want to dive deeper into this topic.

First head on over to the Google Chrome Store. Install Cleanflight Configurator and open it up. The Configurator is a Chrome App that you will use to configure the Scisky.

WARNING: Do not connect the copter to USB with the battery connected. You run the risk of damaging the flight controller.

Flashing Latest Cleanflight

The firmware that came stock on my Scisky is 1.9.0. We are going to upgrade to the latest version which is currently 1.12.1.

Connect your Scisky to your computer using a micro USB cable, then follow these steps in the Cleanflight Configurator.

1. Click the "Firmware Flasher" tab on the left
2. From the "Choose a Firmware / Board" dropdown, choose "1.12.1 NAZE". Make sure your options match the screenshot:
   • No reboot sequence: Off
   • Full chip erase: On
   • Manual baud rate: Off
3. Click the "Load Firmware [Online]" button.
4. Click the "Flash Firmware" button. You will see the progress of the flash and a "Programming: SUCCESSFUL"message when it is complete.

Congratulations! You have just upgraded your Micro Scisky to the latest version of Cleanflight.

In this step, we are going to configure some basic settings for Cleanflight.

Start by hitting the "Connect" button at the top of the Configurator to connect to the Scisky. You will begin on the "Setup" tab.

Setup Tab

Place your quad on a level surface and hit "Calibrate Accelerometer".

Ports Tab

1. Turn on "Serial RX" on UART2
2. Hit "Save and Reboot"

Configuration Tab

1. Turn "MOTOR_STOP" on.
2. Set "Minimum Throttle" to 1000.
3. Set "Maximum Throttle" to 2000.
4. Select "RX_SERIAL" from the "Receiver Mode" list.
5. Select "SPEKTRUM1024" from the "Serial Reveiver Provider" list.
6. Click "Save and Reboot".

Once you have completed the configuration tab, go back to the ports tab and make sure Serial RX is still enabled on UART2. Then go back to the Configuration tab and make sure the "RX_SERIAL" option is still selected. If you need to change the settings again, make sure you save before moving to the other tab. I have noticed times where Cleanflight likes to forget my RX changes for some reason.

CLI Tab

We need to change one more option so go to the CLI tab.

1. Type "set motor_pwm_rate = 32000" into the box at the bottom of the CLI tab and hit enter. You should see the text output above confirm your entry.
2. Type "save" and hit enter. The option will be saved and the board will reboot.

Binding Your Radio

With basic configuration of Cleanflight out of the way, it is time to bind to a radio. When the Scisky is first powered up, the red LED flashes slowly indicating that it is looking for a bound radio. If after 10 seconds, it does not find a radio, it enters bind mode and the red LED flashes quickly.

1. Connect the Scisky to USB.
2. Wait 10 seconds for the red LED to begin flashing quickly.
3. Put your radio into bind mode. Consult the instructions for your radio if you need help with this. If you are having trouble binding, try holding the antenna of your radio very close to the Scisky antenna, like almost touching.
4. When binding is successful, the red LED on the Scisky will turn sold.

Receiver Tab

With the radio bound, it is time to setup the receiver. Connect to the Scisky in the Configurator and head over to the Receiver tab.

Move the sticks on your radio and observe the channel values. If the channels that are changing in the Configurator do not match what you expect based on the stick you are moving, change the "Channel Map" until they do. Note: you will need to hit "Save" before the "Channel Map" changes take affect.

In the next section, we will be assigning an AUX stick to arm your copter. Arming is a step for safety and tells the copter that you are ready to fly. The motors will not spin if the copter is not armed.

Find a switch that you would like to use to arm and see if it moves an AUX channel. A three position switch works best for this if you have one. Once you have found the switch that you would like to use, remember the AUX channel number that it manipulates. I am going to be using AUX 1.

Modes Tab

Now it is time to setup arming and flight modes so open the Modes tab.

WARNING: You are going to be arming the copter in this step to test the settings. Make sure the battery is not connected.

1. Click "Add Range" in the ARM section.
2. Set the AUX channel that you picked for arming.
3. Move the sliders to set the range of the channel that you want to specify as "Armed". In the image above, my arm switch is setup to be disarmed in the up position and armed in the middle and bottom position. You can move the switch on your radio and observe the green tick move indicating the current position.
4. Click "Add Range" in the ANGLE section.
5. Set the AUX channel that you chose.
6. Move the sliders to select the entire range. This means that the copter will always be in Angle or self leveling mode. If you are familiar with flying in rate mode, you can set this slider up accordingly. You can read more about flight modes here.
7. Click Save.

Installing Top Plate

Install the top using nylon machine screws and nuts. You can cut the nylon screws to length once they are installed, or you can use them as landing legs.

Attach a rubber band to the top plate using the hooks. The rubber band is used to hold the battery in place. I like to use the rubber band to help keep the battery cable out of the way as well.

Installing Props

The props on a quadcopter alternate turning clockwise and counterclockwise around the frame. The prop spins towards the edge of the prop that is higher, known as the leading edge. An easy way to remember how to install the props is to turn them to form parallel lines across the front and back of the quad. The inside edge, closest to the body of the quad will always have the leading edge facing the opposite prop. Take a look at the picture for a visual explanation.

Maiden Flight

Now it is time to test out your work so far. You won't have the FPV gear installed yet but it is best to test line of sight for your first flight.

Turn on your radio and plug in the battery. Now arm the copter using your transmitter switch. Slowly take off and enjoy your first flight!

Congratulations! You have just maidened your custom built quadcopter!

If you are new to quadcopters I would suggest stopping at this step for now. Practice and improve your flying skills. It may be challenging at first but with practice flying these little machines will become second nature.

When you are ready to install FPV gear, check out the next step.

Introduction

I am going to describe an easy approach to wiring up the FPV gear. While the video transmitter is capable of transmitting on different frequencies, for the sake of simplicity, we will use the default frequency of 5865MHz.

Because the video transmitter and camera like to run on 5v, we will be using a voltage regulator to boost the battery voltage to 5v for the FPV gear.

Laying Out Components

Get your frame top, video transmitter, camera, and voltage regulator ready. It's time to install the FPV gear.

Test fit the camera in the camera mount. Observe where the camera will sit when installed. Lay a bead of hot glue inside the camera mount where the top edge of the camera will sit. While the glue is still hot, quickly push the camera into the mount. Be sure that the microphone and wires are facing up with the top laying flat; this is the bottom of the camera.

Use hot glue or double sided tape to attach the video transmitter and voltage regulator as shown.

Wiring It Up

Carefully follow the wiring diagram in the attached image to solder up the connections. You can use the extra wire from the camera wiring harness to complete all of the connections. You won't need the connector that comes with the camera.

The Scisky will already have the battery pigtail connected but you can power the voltage regulator from the same solder pads. Take your time and make sure you get all of the connections right.

Optionally, you can use a connector between the voltage regulator and the Scisky to make it easier to remove the top of the frame for repairs.

WARNING: Do not connect the battery just yet. Video transmitters can be damaged if they do not have an antenna attached.

Connecting the Antenna

Strip the insulation off of a 2 inch length of solid copper wire and solder it to the antenna pad of the video transmitter. Once it is soldered in place, cut the antenna to exactly 12.8mm. It is important to cut the antenna to the correct length. The length is tuned to the frequency in which the video transmitter is broadcasting. The antenna length is tuned to the quarter wavelength of 5865MHz, found using this handy calculator.

Testing

Double check all of your connections, then check them again. Once you feel confident in your work, plug the battery in. Power up your goggles or monitor and search through the channels. If all went well, you will see the video being transmitted from your new FPV quadcopter!

Now you are ready to assemble the frame and take it for a FPV test flight.

WARNING: The video transmitter can become hot, especially without the cooling of wind and spinning props. I don't like to leave the battery connected for very long if I am not flying to avoid damaging the transmitter.

If you made it this far, I hope you have enjoyed my Instructable. If you have any suggestions to make it better please let me know.

Enjoy your new FPV quadcopter :)!