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Reference Build: M4 Ladybird with Quatos

The M4 autoquad board was designed to fit the frame for one of the most popular and sold pocket quads ever: The Walkera Ladybird V2. Due to the massive popularity of the Walkera Ladybird, parts for it is available all over the world and you can get frame, motors, props and battery for around 20-25 Euro.

Putting it together is very simple. You just need to mount the controller and arms with 4 screws and solder 8 motor leads in total.

Parts you will need:

Original Ladybird frame. Beware of clones:
Motors and arms is a set. You need to get 2 clockwise (CW) and 2 counterclockwise (CCW) motors:
You will also need at least one 1S lipo battery. This one claims to be 380mAh 25C or 35C and is usually sold as a replacement battery for Hubsan X4 and Walkera Ladybirds. It weighs about 10 grams and will usually give between 6 and 9 minutes flight time depending on take off weight. Quality of individual cells can vary, but they are cheap.You can substitute with any similar weight and density battery from a name brand, but be aware to make sure it fits in the battery tray. Higher C ratings is preferred. BE VERY AWARE THAT SOME BATTERIES COME WITH REVERSED POLARITY – MAKE SURE THAT BATTERY POLARITY IS CORRECT BEFORE PLUGGING THE BATTERY.
Props are needed too. We recommend the original Walkera Ladibird propellors, but Hubsan X4 or YD117 props will work too. See further below for a table of thrust curve values for different propellors.
   You will also need a male battery connector pigtail:
TIP: You can source the male battery pigtail from one of these very cheap multiple 1 cell charging harnesses for Hubsan and Walkera batteries. They are also pretty handy for charging multiple batteries on a balance charger, so get an extra. They come for 3 and up to 6 cells:

Assembling the frame

There is really not much to it. The arms slide into the body and is held in place with the same screws that hold the flight controller. Just slide in the motor arms to begin and mount the small rubber grommets that supports the board.

As the motors are built for either CW or CCW rotation, it is important that you place the right motors in the right places.This example is for a X-quad configuration so make sure the motor rotation is set up correctly, so that the front left motor is running clockwise. Refer to below table:

Preparing the M4 board

Cutting the arms:
To build a Ladybird, you need to remove the small arms that is part of the board. They can be cut with a sidecutter, pianowire-cutter or similar tool. Make the cut just above the arm number. A little bit of sandpaper or a small file can be used to clean it up afterwards.

Battery lead: Solder a battery lead to the + and – pads of the M4 board. MAKE SURE THAT POLARITY IS CORRECT, there is no reverse voltage protection on M4 and plugging a reverse voltage source will likely destroy you board.

Radio Power: For Version 1 boards, to use the onboard Deltang 7channel DSM2 receiver, you need to supply it with 3.3V from the onboard stepup regulator. This is done by placing a wire jumper from the PWR pad of the radio connector to the top pad of the Radio power jumper. MAKE SURE THE SUPPLY LINE IS ONLY CONNECTED TO TOP PAD – Confirm with multimeter!

Radio antenna: The antenna for the onboard radio is just a piece of wire to form a dipole antenna. The exact length of the antenna should be 31.25mm from edge of pad.

Here is how it should look afterwards:

Then mount the board with “1” facing towards the front left motor:

And connect the motors to connectors M1 through M4. Observe polarity. Red wires go to plus pad, black wires to negative pad:

And you are basically done. You can add a GPS antenna to add waypoint and navigation capability, but otherwise its ready to be flashed and setup.

Firmware flashing and board setup

First thing to do is to flash the correct firmware. Depending on if you are using the Onboard Deltang Receiver or an external R/C receiver, you need to load the corresponding firmware:

If you are using the Deltang onboard receiver, you need to flash firmware for 8.5 board:

8.5 firmware download

If you are using an external reciever, you should flash firmware for an 8.4 board:

8.4 firmware download

Refer to the M4 – Installation and Setup page for details on flashing firmwares to M4 boards.

Loading parameters:

You will need to load the right parameter file for a LadyBird with Quatos. The file can be downloaded from this link:

LadyBird configuration file

Propellor selection

The default configuration is set up for the original LadyBird propellors.

Should you desire to use other propellors, you will need to load new thrust curve parameters to the controller. Below is a few popular choices:

Hubsan X4 propellor – good alrounder, runs quiet and slightly more efficient than the LadyBird props. But look out for cheap clones with bad balance and overweight issues. Replace if they become nicked in a crash, they can give nasty vibration problems if the tips are dented or nicked.

Use the following params for Hubsan X4 props:

MOT_VALUE2T_A1      0.088645289
MOT_VALUE2T_A2      0.000495285


This page was created on 19-Aug-14 by jussi. Last modified on 28-Dec-14 by kinderkram.