Category: Bluetooth

Remote control with gamepad or joystick

Overview

In the previous article we already presented the possibility to control up to eight servos via a USB interface using a joystick or gamepad, a PC and a PiKoder/SSC. Here is now described how a wireless model remote control can be realized with a PiKoder – receiver, the PiKoder/SSC RX. Bluetooth for command transmission.

Setup

First, the PiKoder/SSC RX must be connected to the PC at the operating system level. For this purpose, you first search for new Bluetooth devices in the device control.

After a short time, the Bluetooth module of the receiver should be offered. The PIN is “1234”.

With the selection “Connect” the coupling (pairing) takes place on system level.

As the following view from the device manager shows, the coupling of the system also establishes two virtual serial interfaces, which we access later in the program for establishing a connection.

This completes the setup and the JoystickRC program can now be started as described in the previous post.

Open Source Android App for Bluetooth R/C

Overview

The “picCAR” App turns an Android-Tablet or Smartphone with Bluetooth into an R/C transmitter.

The app is based on the Cxem Car 1 Open Source Projekt. The app has been extended and revised to interface with a PiKoder/SSC RX receiver.

The picCar app is open source and released under a GNU General Public License Version 3. The app can be installed via the Play Store. The source code is provided through github.

User interface

picCar Main activity

The user interface of the picCAR app is pretty intuitive and straight forward. You can select one of four control modes by touching the respective screen button: button control, a virtual joystick, accelerometer (control by moving the device) and a combination between accelerometer and a slider. The Bluetooth connection would be established once the mode has been selected.

For building your receiver please refer to the PiKoder/SSC Bluetooth receiver page. The App is supported by all PiKoder/SSC firmware versions. It is recommended though that you use a PiKoder/SSC firmware 1.03 or above in order to deploy the TimeOut-Funktion of the Android app.

picCAR User’s Guide (.pdf File, EN)

The picCAR User’s Guide describes the picCAR app in detail.

Download Now!

Open Source Arduino Digital RC Transmitter

The sketch ArduinoDTX implements a feature rich RC addressing all needs of a state-of-the-art transmitter on an Arduino. It is based on fully digital encoding of all control information in the miniSSC – protocol rather than using a PPM frame. This fully digital encoding enables transmitting over a transparent serial channel such as Bluetooth, Wifi, and XBee. As a receiver for e.g. Bluetooth a PiKoder/SSC RX would be deployed.

This digital RC transmitter is based on the Open Source project arduinorc by Richard Goutorbe and thus inheriting the respective full feature set such as:

  • up to 9 proportional channels (Nano), 6 channels by default (Uno)
  • up to 6 additional digital channels (switches)
  • 9 model memories
  • Dual rate/Exponential switch
  • Throttle cut switch
  • 2 programmable mixers
  • End point adjustment, Potentiometer and Servo calibration
  • Throttle security check at startup
  • Optional Transmitter battery low voltage alarm
  • Programmable with Linux or Windows via USB (terminal application)

The original arduinorc-sketch has been modified and became the ArduinoDTx sketch, which outputs all channel information in the miniSSC-format rather than a PPM-pulse frame on Arduino pin D6. Every time a stick position would change a miniSSC message is generated. The PPM output has been removed completely.

The ArduinoDTx sketch is open source and provided through a respective github repository under the terms of the GNU General Public License Version 3.

Prototype setup: Digital four channel RC

Schematic setup of the Arduino Digtial RC transmitter

An RC transmitter with four channels will serve as a prototype project. As shown in the image two Thumb-Joysticks are evaluated by the Arduino (Pot 1/2 and Pot 3/4 in the above schematic). The connection to the Arduino’s analog pins is through a proto-shield. This shield does also accomodate the mode switch and the LED with the respective 270R resistor.

The RC is designed for battery operation. To guarantee the required minimum voltage of 6 V for the Arduino – even when using rechargeable batteries with a nominal voltage of 1,2 V – a battery holder for five AA elements has been selected. The two side panels support your palm operating the remote control and would enhance the user comfort significantly.

Please note that the USB port of the Arduino is easily accessible. This allows you to download software upgrades but also to customize the RC to your application.

Commissioning and testing

Test setup Arduino Digtial RC transmitter

For commissioning the RC you would download the arduinodtx sketch (.ino-file) which is provided through an respective github repository. Please note that building the sketch requires the Arduino “TimerOne”-library.

After you have uploaded the sketch to your Arduino the easiest way to test the RC would be to build the “wired remote control” shown to the right using a PiKoder/SSC evalutation board. In the standard configuration the pots 1-4 would control the respective servo channels 1-4 of the PiKoder/SSC.

If you wanted to customize your RC transmitter then you would hve to follow the steps described on the arduinorc-page. All commandos for programming the arduinorc are still available to you – for more information please refer to the (arduinorc command documentation).

Using Bluetooth communication

Bluetooth shield configuration for Arduino Digtial RC transmitter

You can easily customize the digital remote control to a Bluetooth RC with an ITEAD-Bluetooth Shield and then use the PiKoder/SSC RX as a readily available and fully compatible 8 channel receiver. Since the transmission is based on a tranparent serial protocol there are no changes needed in the sketch and the complete feature set is also available for the Bluetooth RC.

The transmitter setup is shown in the image. Prior to operating the RC the connection between the wifi modules has to be configured. Please refer to the PiKoder/SSC RX User Manual for a detailed description.

Using WLAN communication

You can also easily customize the digital remote control to a Wifi RC by adding a logic level converter, a dc-dc converter, two jumpers as UART multiplexers (to allow for programming the wifi radio) and an ESP8266-01 Wifi module and then use the PiKoder/SSC wRX as a readily available and fully compatible 8 channel receiver. The hardware setup and the programming of the wifi radios is described in great detail in the blog Arduino WLAN RC Transmitter.

Additional Application Examples

In order to increase the range of your radio control you can upgrade from Bluetooth to XBee. The setup is described in the blog Arduino based XBee radio control and in the PiKoder/SSC Application Note #3: XBee Communication.

Arduino WLAN RC Transmitter

The Open Source Arduino sketch arduinodtx implements a feature rich state-of-the-art RC transmitter with a serial command output (PiKoder/SSC compatible). The transmitter commands would be sent via a transparent serial channel.

Therefore, a wifi communication module such as an ESP8266-01 can be used in concert with a PiKoder/SSC wRX wifi based receiver to easily build a feature rich radio control.

In addition to the components for the basic setup of the arduinodtx you would need a logic level converter, a dc-dc converter, two jumpers as UART multiplexer and the wifi module as shown in the image above. The wiring of these building blocks is shown below (you would have connect all signals with identical names):

The setup is fairly simple and can be easily done on a prototype board. Please note that Arduino signals are shown in blue.

Then you would have to configure the transmitter’s wifi radio to establish a transparent link to your receiver radio – similar to binding a transmitter and receiver in a standard rc environment. This would be done by setting the jumpers as shown above to connect the radio directly to your computer. Please refer to ESP8266-01 Sketch for the PiKoder/SSC wRX for more information. If you would want to program the ESP8266-01 while in place you would have to add the additional components for the programmer to the prototype board.

Please note also the setting of the jumpers for D0/D1. Please make sure that the Arduino would not interfere with any direct communication with the ESP8266-01 by connecting the Arduino´s RESET signal to GND.

After completing the programming of the ESP8266-01, the adjusting of the jumpers, restarting of the Arduino and rebooting your RC would be fully operational.