Arduino – Maker Projects

Arduino remote control transmitter with iRangeX multi-protocol module

The previous blog describes the Arduino PPM encoder. Together with a multi-protocol module, you can set up a complete remote control transmitter with little additional effort.

To do this, adapt the module using an Arduino prototype shield. However, not all shields are equally suitable. Some shields do not have a hole pattern in the lower right area but a specific layout like the red circuit board in the picture. But you need a prototype board with a complete breadboard like the blue circuit board.

You make the electrical connection between the Arduino and the module with a five-pole pin header with extra-long pins. Insert the pin header into the socket header on the back of the module. Then position the module on the prototype shield and find the correct position for the module and the soldering points that you need to use.

To ensure a secure hold, I have also provided Velcro tape. Since this additional intermediate layer changes the height of the soldering pins again, you can only solder the pins now.

The wiring for the power supply and for the PPM signal can be found in the picture. The assembly is completed when the module is plugged in.

USB2PPM by Arduino

My previous blogs about connecting a joystick to a model remote control via USB have always used one of my PiKoders. But of course an Arduino can also take over the PPM signal generation.

To implement this idea I created an Arduino Sketch USB2PPM_by_Arduino (Open Source), which you can find on Github . The program implements a PPM encoder whose parameters and channel values are set via serial commands.

For example, you can switch the polarity of the output signal and select the number of PPM channels in the range from one to eight in order to adapt the encoder to your transmitter.

The PPM signal can be found on pin D8. To connect to the student input of your model remote control, you will then need a corresponding cable. It may also make sense to use an Arduino prototype shield that accepts a suitable socket to ensure a stable connection.

For the integration of the PPM encoder into your application, the definition of the commands and messages can be found in the header file protocol.h.

Additionally you will find the Joystick2PPM4Arduino app in the Microsoft Store with which you can connect a joystick or gamepad (DirectX-compatible) to your Arduino-based PPM-Encoder. The app connects to the Arduino Uno, Nano and Pro Micro.

Arduino Pic Programmer

Overview

If you would search the internet you will find quite some DIY pic programmers. However, those designs often either require a true serial or parallel port instead of an easily available USB port or are designed around a pre-programmed controller assuming access to a programmer.

A compelling alternative would be the use of an Arduino as in the ArdPicProg. Load the Arduino sketch, the host program and add a prototype shield with a very limited number of additional components to build your pic programmer. This programmer features also a ICD connector and an RJ-11 jack (ICD2) interface. The complete project including hard- and software is open source and is released under the GNU General Public License Version 3. You can build your own ArdPicProg by using the especially designed PCB.

The complete setup and the application of the ArdPicProg is described in more detail in the User’s Guide.

Download User Guide ArdPicProg (.pdf, EN)

Host-Software for ArdPicProg

For programming a pic controller a host software would be required. You can select between two options: the terminal program “Ardpicprog” or the “Arduino Pic Programmer” (ArdPicProgHost) with a Windows based graphical user interface. The source code for both programs is Open Source and would be available for download on github.

Arduino Pic Programmer (ArdPicProgHost)

This windows application offers a modern and intuitive way of programming a pic controller.

Controllers which are supported by the Arduino Pic programmer can be read, erased, and written. The user interface and the program options are also described in the User’s Guide.

ArdPicProgHost was programmed with Microsoft VB2010 Express and is released under a GNU General Public License Version 3. The source code is provided through a github repository. The executable (Release 0.2.7) can be downloaded here:

Download ArdPicProg.Exe (.zip Datei)

The software does not require any installation. After downloading and unzipping the program can be executed right away.

PicProgHost (terminal program)

You could also employ the host application “PicProgHost” for programming pic controllers which offers a terminal interface. The application is based on the open source Ardpicprog host software you would find on the ArdpicProg project pages. These pages also provide for a suitable documentation of the program operation.

The original source code has been migrated to a Qt 5 environment and the most recent version is now capable of handling COM ports > 9. The can be downloaded here:>

Download PicProgHost.Exe (.zip Datei)

The source code is available on github. The line commands are fully backwards compatible to Ardpicprog – therefore please refer to the ArdPicProg project pages for more information.

There is no program installation required. The user interface is also described in the User’s Guide.

Arduino sketch “ProgramPic”

The “ProgramPic” Sketch which is required for using the Arduino ArdPicProg shield is released under a GNU General Public License Version 3 The sketch is provided through the ProgramPic github repository.

ArdPicProg printed circuit board

The ArdPicProg PCB is available in the shop.

RC model control with web browser – improved user interface

A few days ago I came across the ESP8266 MikroE Buggy project.

In this project, a web server is implemented on the ESP8266 – similar to my blog Model Remote Control with Web browser. Using this concept, a browser based (and therefore operating system neutral) radio control could be easily made available. In this project, especially the HTML5 based user interface implementing a joystick caught my attention.

The software is open source and so I was able to change the program for use with a PiKoder/SSC wRX. Additionally, I adapted the code for controlling a ‘normal’ car or boat (one channel for speed, one channel for direction). The customized source code is available in a github repository.

The programming of the ESP8266 is also described in the web browser model remote control blog. An additional feature of the ESP8266 MikroE Buggy project is that the Arduino file system is used. The installation and use is described here.

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.

ESP8266-01 Sketch for the PiKoder/SSC wRX receiver

The PiKoder/SSC wRX uses the ESP8266-01 module configured as an Access Point (AP) to implement a transparent serial communication channel between a transmitter a PiKoder/SSC. The ESP8266-01 can be programmed as needed based on its default firmware by using respective AT commands. However, given the number of parameters used for the commands this approach is complex and rather error prone. In addition, the verification of the programming is difficult and mistakes very often require to re-flash the ESP8266.

It has turned out to be significantly easier to flash the ESP8266-01 with a dedicated sketch, which implements all the features required for the serial communication and offers an additional command interface for setting the AP parameters needed.

This sketch udpRC_ESP8266-01 is Open Source and is provided via github for download. The sketch will be compiled and uploaded to the ESP8266-01 via the Arduino IDE as described in the blog RC with your webbrowser.

The use of the re-programmed module is very simple and intuitive. After rebooting the sketch would check the non-volatile memory of the ESP8266 for a valid parameter set. If no parameters are found then the default values will be used. After rebooting the the Controller is ready to operate.

The screenshot shows the user interface and the available commends. After rebooting the ESP8266-01 sents a more or less unreadable stream of characters to indicate that it is ready.

Entering the command ‘$?<cr><lf>’ will echo the current parameter setting. The SSID of the AP would be changed with the command ‘$s=’ followed by <cr><lf> and for changing the password you would use ‘$p=’. The revised parameter will be stored right away but will only be applied after a reboot. You can always check the changed parameter settings with ‘$?<cr><lf>’.

Radio control with your webbrowser

If your rc model would offer an access point and run a webserver, then you could control your model with a webbrowser running on your smartphone – no matter whether this is a Windows or Android device or an iPhone.

The PiKoder/SSC wRX (see below) is well suited as a hardware platform for this concept: the ESP8266-01 offers the access point and runs the webserver, the PiKoder/SSC manages all realtime aspects of controlling the servos and the electronic speed control.

PiKoder/SSC wRX

The standard configuration of the PiKoder/SSC wRX requires the ESP8266-01 to act as a transparent bridge. Since we will be needing a webserver, we would have to flash this wifi controller with a new firmware. This can be easily accomplished by using the latest Arduino IDE which is supporting generic ESP8266 modules.

The new controller firmware is open source and would be available through the github repository makerprojects/httpRC. After downloading open the sketch in the Arduino IDE. At the beginning of the source code you will find the settings recommended for compiling the program. [Update December 27, 2018: The httpRC sketch has been completely revised and updated. Please check this blog for more details.]

In order to flash the ESP8266-01 you will need an USB-Serial converter, since the wifi module does not feature a USB port. Please keep in mind also, that the ESP8266 requires a supply voltage of 3,3 Volts – the board is not 5 V tolerant! The offering of USB-Serial converter offering a 3,3 Volt supply as well as 3,3 Volt signal level is limited; therefore it might be easier to use a converter with 5 V supply and 3,3 V signal level such as the PL2303TA readily available at ebay (shown below) and build your own converter from 5 V to 3,3 V.

USB-Serial connector

Since you would need a “reset” and “program” button for flashing the module you might consider to construct the little adapter shown below using a prototype board.

Programming adapter for the ESP8266-01

The schematic for the programming is shown below.

The conversion of the 5 V provided by the USB-Serial adapter to 3,3 V follows the design of the PiKoder/SSC wRX and requires a standard low drop voltage controller LF 33 CV ( please refer to the following excerpt of the PiKoder/SSC wRX schematic; the 5 V input would be to the left, the output is to the right).

Unfortunately the flashing of the ESP8266 does not start automatically as you might be used to when downloading a program into your Arduino but has to be initiated manually. You would push the RST and PROG button simultaneously and release the RST button while still holding the PROG button. After releasing the PROG button, the module would be in flash mode. Now you would start uploading the program. Now you would start uploading the program. Once the upload is complete your controller would require another reset prior to being operational. Once the upload is complete your controller would require another reset prior to being operational.