The stock ESC that comes with the ZOHD Dart 250g (and probably other ZOHD models), was proving hard to calibrate until I understood the reason.

If the zero throttle position is not captured within 3 seconds of applying battery power to the ESC, it will enter "programming mode" and an endless loop of beeps!

This means you need to zero the throttle immediately (within 1 second) after the 2 initial short "beep-beep" tones. The "manual" implies that you have 3 seconds after the 2 initial "beep-beep" before it enters programming mode. You don't, you have 1 second only.

This will be true if you calibrate via iNav (Outputs tab), or a PWM receiver.

Although I can display some telemetry data on the screen of my Radio, it is not possible to overlay the flight track on a map in real time without a ground station computer.

Since my latest plane build uses iNav, and I found a neat Android app to do this and more (Telemetry Viewer), I decided to create this solution as I already had a HC-05 Bluetooth module preconfigured for 56700 baud and paired to my phone.

The BT module is connected to the Smartport connection on the radio. In my case I have an XJT module in the back of the Turnigy 9XR Pro which has a Smartport connector (other radios sometimes have the Smartport connector in the radio case).

The Smartport signal from the radio is inverted, so it is necessary to uninvert it by means of a cheap "SBUS" inverter board. The wiring is very simple (3 inputs & 3 outputs):

5v power to 5v power
Ground to ground
Smartport signal to BT RX

The Telemetry protocol on the radio is set to "Frsky" so that the raw telemetry data is simply relayed from the flight controller through the radio to the BT module.

The default serial speed of my HC-05 is 9600 baud which was fast for serial communications in 1975, but I decided to increase it to 57600. The module is connected to serial port 5, so I needed to set the SERIAL5_BAUD to 57. This can be done in various ways, depending on your Ardupilot ground station software.

To change the serial speed on the BT module it is necessary to use a USB/TTL adapter to set the device in "AT" mode which on my module is achieved by holding down a button switch while powering on. In this mode the default speed is set to 38400 baud, so I configured the communication speed on the terminal software to match.

Using the terminal software (Serial USB Terminal on Android phone), I connected to the USB/Serial converter:
AT
OK
AT+UART=57600,0,0
OK

After disconnecting and rebooting, I was able to connect to the ground station at a much faster speed via BT

The Frsky X8R receiver sends RSSI data back to the XJT Frsky transmitter module so it can be displayed on the radio. However, I wanted to also display it on my groundstation. I believe the same applies for OSD.

The RSSI signal lead on the X8R receiver is connected to the RSSI pin on the F405-Wing. The receiver is connected to the FC via SBUS.

I have set the Arduplane rssi params:
RSSI_TYPE 1
RSSI_ANA_PIN 15
RSSI_PIN_HIGH 3.3
RSSI_PIN_LOW 0.25

RSSI values are displayed as percentages.

Having successfully installed a SiK radio, I decided to try connecting a BT module to perform the basic function of modifying Ardupilot parameters using my Android phone.

My first mistake was to buy a BLE (low energy) module. After some frustrating time, I concluded that this was not going to work which was confirmed by a fellow RCG member. Fortunately I was able to get a refund from Amazon and then purchased a HC-05 "classic bluetooth" module.

First step was to confirm the wiring between the BT module and the F405. I am using the S5 UART so:

5v to 5v
Ground to ground
T5 to BT RX
R5 to BT TX

Since the default baud rate of the HC-05 is 9600 baud, I preset the Ardupilot parameters:

SERIAL5_BAUD 9 (9600)
SERIAL5_PROTOCOL 1 (MAVLINK1)

N. B. The serial ports require power from the battery, not USB.

I use Qgroundcontrol to modify parameters via my Android phone. In order to do this via BT, I first paired the module via Android Bluetooth settings. The HC-05 PIN is 1234 by default.

In Qgroundcontrol, it is necessary to add a new "Comm Link" which can be found in the "Q" menu. It is only necessary to set the Type to Bluetooth. The name can be changed if desired. The device should be found by selecting "Scan" and selecting the HC-05 which will then populate the Bluetooth link settings.

Returning to the "Comm Links" page, it is now possible to select the HC-05 device and Connect.

Switching to the main Qgroundcontrol screen will show the vehicle connection has been made and the parameters from the flight controller being downloaded. Full functionality of the ground station is then available via BT with a range of 20+ metres.

I have been gradually adding various peripherals to the FC in preparation before installing in a model (TBD).
Adding the SiK radio allows me to easily edit parameters without using a computer. I use Qgroundcontrol on my Android phone.

N.B. Check the USB-OTG cable/connection to the ground station. For Android, I would recommend "Easy OTG Checker".

Wiring:
I made a cable connecting a 4 wire servo connector to a 6 pin DF13 (in my case a JST for the Hobbyking radios).

Red: 5v to 5v
Black: Ground to Ground
Yellow: R1 to radio TX
Green: T1 to radio RX

Parameters:
SERIAL1_BAUD 57
SERIAL1_PROTOCOL 1

I have been playing with Clearview on the iPad and they have a PC based version (Java) which is around $40. I wanted to use the trusty 9XR Pro but did not want to be tethered to the computer, so went looking for a wireless solution.

What I found was the Orange ORX USB Wireless dongle (Frsky protocol) which I got from Hobbyking for around $15. This device has a Frsky D series compatible receiver and appears to the PC as a HID game controller. They also sell a DSMx protocol version.

My situation was slightly complicated since I have a Macbook running Parallels with Windows 7.

The first step is to bind the dongle with transmitter which in my case is an XJT. The dongle works in D8 mode, so I changed the dip switches on the XJT to match. However, after getting everything working, I put the switches back to X16 -- and it still worked!?

You need to press the button on the dongle when inserting it, presumably to put it in bind mode since the blue light flashes.

I made sure that I could see the new USB device in Windows in the game controller control panel and noticed that Windows installed a suitable driver for it.

On the radio, I created a new model using the basic 4 channel template. Then I went to "Protocol" page and set:

External Module ON
Proto XJT
RxNum {unused #}
Type D8
Chans 8

I saved the model and went back to the Protocol page and hit Bind. I have to admit I had a few attempts at binding, but at some point the blue light on...Continue Reading