HOWTO drone wiring (2) – Rx/APM/ESCs

Keeping notes on the founds and tested of my quadcopter.

APM outputs to ESCs

APM channels
3       1
    X
2       4
CC3D (my motors setup)
1        2
     X
4        3
So APM outputs (1234) to motors (2413)

Output pins top-down are signal, 5V, gnd… to ESC color code Y.R.Br. 黃紅棑
Picked out all reds (BEC i.e. 5v, I powered APM using solely PMU)

Radio receiver channels (TAER)

1. (T)hrottle 油門
2. (A)ileron    i.e. 'Roll' 橫滾
3. (E)levator    i.e. 'Pitch' 俯仰
4. (R)udder     i.e. 'Yaw' 偏航

APM inputs {123 4} = {AET R}

Radio Mode 1 (mode 2 has 2 & 3 swapped)

HOWTO drone power – LiPo battery charging and storage

Understanding the numbers on a battery

I have a 3S 2200mAh 35~70C LiPo battery:

Each battery cell is rated 3.7V*
3S means 3 cells, 3.7 x 3 = 11.1V
2200 mAh is the capacity, also means one unit of current (1C) is 2200mA (or 2.2A).
If discharging at this rate, last for an hour.

35C is the normal max, 70C at burst.
35 x 2.2A = 77A, and 154A, respectively.

* The voltage per cell is actually 3.7V +/- something… ranging from 3.3V (low, not empty) to 4.2V (full)  i.e. 10V ~ 12.6V on a 3S

Never go empty, or the battery will be damaged.
3.0V is deadline to kill a LiPo.
I choose 10.5V as warning, must return home and land before 10V.

Charging (≤ 1C)

To charge a multi-cell LiPo, you need a balance charger which takes care of the slightly chemical difference among the cells.

The rule is 1C for charging.  Over current heats up the LiPo, and the heat kills the LiPo.
2200 mAh battery means 2.2A max.  I won’t go max.  2.0A is good… longer life if you don’t push it hard.

Storage (rated)

Voltage actual means levels difference of charges between positive and negative poles, so pressure chemically.

If you won’t use the LiPo for very long time, store the battery at roughly the rated voltage, 3.7V.
A new battery I have was 3.8V when arrived.

Discharging (80% rule)

In case you need to discharge a battery for storage, apply this rule.  80% of 1C = .8 x 2200 my case = 1.7V

Battery alarm

Handy little thing (~$6) you could mount on your drone.  Yell loud when voltage low.  Black wire always starts first to the left most of the pins.

HOWTO drone wiring (1): FPV-Cam/OSD/VTx/Telemetry

One picture tells it all 一張圖教你接線

Writing on the phone screen is tough, readable?  ;)

The tricky part is the power flow. On OSD, voltage comes from the video-out side, and is fed back to the video-in side powering up the camera.

For telemetry, North America uses 915MHz, Europe uses 433MHz. Google for detail.

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References (downloaded) below:

OSD 飛行資訊 (you need this for the ironman thing)

Video Tx 圖傳