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Micro Quad with 8mm Brushed Motors


Here is my build of an nice FPV micro quad with 8mm brushed motors.  Good performance; cheap to build.  The flight controller can run Cleanflight or Betaflight firmware.

Update 2/2017:

I've rebuilt the quad with a new flight controller and camera; an updated parts list is below.  I'm quite happy with how it's flying, running Betaflight v3.0.1 F3EVO firmware with my 'horizon_tilt_effect' patch.  See here for settings I've been flying with.

See here for a gallery of pics.
FPV video flying this build:  AVI file  /  YouTube

Notes:  I have the prop rotation opposite the original Cleanflight "standard" and the 'yaw_motor_direction' setting at '-1'.  I replaced the camera's antenna with a simple piece-of-wire antenna; length of 30mm works well with 5.8MHz frequencies (5/8 wavelength).

Parts List:

Micro 32bits F3 Brushed Flight Control Board Based On SP RACING F3 EVO Brush $15.89

OrangeRx R100 DSM2 Compatible Satellite Receiver

Micro-JST-1.25 sockets (4) $1.00

CL-0820-15 - motor set, direct drive (speed: fast) $27.00

Diatone Beta110 H4 V1.0 CF Frame Kit 366000141-0 $10.95

Hubsan X4 H107C Propellers 55mm

Turnigy Graphene 750mAh LiPo Pack 1S 65C w/ JST-SYP-2P $8.65

Turnigy nano-tech 750mAh 1S 35-70C Lipo Pack $3.21

Super Mini Light AIO 5.8G 48CH 25mW VTX 520TVL 1/4 Cmos FPV Camera PAL/NTSC $23.99

CUI Small Buzzer (9.6MM radial) CX-0905C Digikey 102-1285-ND $2.47

Male JST Battery Pigtail 12cm Length (10pcs/bag) $1.92

Mini Plug Extention for Micro Battery 10cm (5pcs/bag) MINIJST-EXT5

Original post:

See here for a gallery of (older) pics.
See below for videos.

The controller board, sold as the Quanum Pico or the Micro Scisky, is fully Naze32 compatible and includes power outputs for 4 brushed motors, and a Spektrum-compatible receiver.  An rcgroups discussion thread on it is here:  http://www.rcgroups.com/forums/showthread.php?t=2466286

With the four CL-0820-15 motors and Hubsan X4 H107C props the quad has good power and responsiveness.  The performance when using the cheaper HobbyKing Mini Quad Brushed Motors and the Hubsan X4 H107C props is not as good (underpowered), but can be improved if the 66mm Parrot Rolling Spider props are used instead of the Hubsans.

I attached pieces of heat shrink to the bottoms of the motors to create landing "legs" and to protected the motors.  I painted some glue on the motors before putting on the heat shrink -- this helps to prevent the motors from coming apart in a crash.  Drilling through the holes on the props is also a good idea (using a 62-gauge or 0.9mm drill); see here.

The Quanum micro-camera/transmitter fits nicely on the front, can be wired in to run directly off the 1S battery (via pigtail connector made from an extension cable), and can be held on with servo tape.  I glued an antenna saver to the side to help protect the antenna.

Weight without battery:  41g
Weight with 750mAh battery:  60g

While the firmware supports buzzer tones (for things like battery alarms and arming tones), the flight controller does not provide a buzzer output.  To access the output, a small wire can be soldered onto the PA12 pin of the CPU, as shown here:

I used 36AWG wire for this, and applying some rework flux before soldering helps a lot.  I connected the output (through a 47-ohm resistor, optional) to a small buzzer, with the other side connected to ground (pics).

It's also possible to add wires for accessing the UART1 RX and TX pins, to support connecting a bluetooth module:

In the above picture, the bottom wire is connected to the UART1 TX (pin 30), which should be connected to the RXD pin on the bluetooth module.  The +5V power for the module can be tapped on one of the 4-pin connectors (using a JST SH cable).

These Cleanflight/Betaflight settings are needed for the flight controller:
feature RX_SERIAL
feature MOTOR_STOP
feature FAILSAFE
map TAER1234
serial 1 64 115200 57600 0 115200
set max_throttle = 2000
set motor_pwm_rate = 32000
Using a Spektrum DX6i transmitter, I set the travel-adjust settings on the transmitter to their maximum values and used the following
Cleanflight/Betaflight settings to achieve receiver inputs close to the desired 1000-2000 range:
rxrange 0 1050 1950
rxrange 1 1050 1950
rxrange 2 1050 1950
rxrange 3 1050 1950
I improved the throttle center-point (where the quad hovers) with these settings:
set thr_mid = 30
set thr_expo = 30
To do fast flips, I use these settings (flying in Horizon mode):
set rc_expo = 80
set roll_rate = 90
set pitch_rate = 90
For the battery-voltage buzzer alarm ("feature VBAT"), I found I needed to lower the 'vbat' voltage settings:
set vbat_min_cell_voltage = 26
set vbat_warning_cell_voltage = 27
The Cleanflight/Betaflight code has a vbat-hysteresis function that adds an annoying time-delay lag to the warning-beep response, especially on 1S setups.  See here for a patch I submitted to deal with this function.  If the 'vbat_hysteresis' configuration parameter is available then it should be set to 0.

I found that using the Betaflight firmware and the LuxFloat PID controller ("set pid_controller = LUX"), the quad runs quite well with the default tuning settings.

Parts List (old):

Quanum Pico 32bit Brushed Flight Control Board 9154000023-0  $32.99

Diatone Beta110 H4 V1.0 CF Frame Kit 366000141-0  $10.95

CL-0820-15 - motor set, direct drive (speed: fast)  $27.00

Hubsan X4 H107C Propellers 55mm

Turnigy nano-tech 750mah 1S 35~70C Lipo Pack  $2.91

2 Pair JST-DS LOSI 2-Pin Connector plug male female with Wire  $1.99 + $1.50

Quanum ELITE TX CAMERA COMBO Micro Cam VTX 25mW 40CH 5.8GHz (NTSC)  $36.68

Mini Plug Extention for Micro Battery 10cm (5pcs/bag) MINIJST-EXT5  $2.22

CUI Small Buzzer (9.6mm radial) CX-0905C Digikey 102-1285-ND  $2.47

Turnigy High Quality 36AWG Teflon Coated Wire 1m

Alternate frames:


Micro Quad with 8mm Brushed Motors Gym Racing 2016-03-23

Micro Quad with 8mm Brushed Motors Around the House 2016-03-26

Here's a file version that may play better:  m8bqv1.avi

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ET Heli