I'm working on an educational robotics project that should allow control of the robot over Bluetooth. The robot is an off-the-shelf robot with a serial interface that the Arduino is driving normally autonomously.
I'm trying to allow users to write a series of commands to the Bluetooth serial port (connected to hardware serial pins or software serial pins) while the automation is still running and when they send a new-line, the series of commands is sent to other parts of the robot.
I've used other microcontrollers and written a simple interrupt routine when a pin is pulled high or low, but I am not sure how to handle an interrupt on a character. I think that an interrupt is the best way to do this, but I haven't had much experience with Arduino, so there many be functionality I'm not aware off.
TL;DR: If I want the Arduino to execute code when a certain character arrives on a serial port, should I use an interrupt method?
I also want to add, as this is an educational project, I would like to stay fully on Arduino, several friends and colleagues have recommended alternate chips or MCUs that would have the functionality but I want to stay friendly to new programmers and engineers.
The built-in HardwareSerial does not have support for interrupt-driven handling of characters. Many sketches are OK with the typical polling approach:
while (Serial.available()) {
char c = Serial.read();
// Code that watches for certain characters
.
.
.
}
There's nothing about what you describe that requires interrupts, but you could use an extended version of HardwareSerial that I wrote (modified), called NeoHWSerial. It calls a function that you provide from the interrupt service routine (see documentation).
Related
I am using ESP8266 (NODEMCU 3.0 or something) to make a quadcopter. Ive connected ardu pro mini to RC receiver so I am reading PPM values from it. Pro mini sends data with tx to ESP8266. ESP reads it with software serial with 115200 baudrate. I am communicating with MPU9255 (Waveshire) via I2C either.
My problem is that I cant fully controll my brushless motors. When I was using arduino instead of ESP8266, servo library was the best and reliable. But ESP's servo library is different, since its not AVR, and problems occurs. First of the servo library didnt want to work on most frequencies. I mean default is 50Hz (20000uS) and in this state ESC of motors did armed but unfortunatelly when changes was fast and short (1250-> 1370 -> 1250) it did miss that change like nothing happnd... This makes my D value in PID controller useless...
Sometimes on 100Hz freq all was working fine, but sometimes not...
When Ive started to use analogWrite only 500Hz was working fine, rest of freq didnt want to arm ESCs.
PS. I am using 3.3V to 5V converter for PPM/PWM pins so I am sure that the signal is fine for ESCs.
PS2. I dont have any osciloscope unfortunately.
The ESP82266 present on your module is a RF transceiver integrated circuit that can handle WiFi communication, both configured as a slave to a microcontroller such as the ones present on various Arduino boards, or as a standalone chip by having it's on-board Tensilica L106 32-bit processor programmed via an external SPI flash memory. If used as a slave, the communication between, for example, an Arduino an the ESP82266 can be done using different protocols such as SPI / SDIO or I2C / UART interfaces. Googling a comprehensive Tensilica L106 user guide on the internet doesn't seem an easy task, and it looks as if some people have already failed to find it. If you're seeking to add Wi-Fi capabilities to your quadcopter the solution I suggest is having the Arduino take control over the servos, motors, etc. and hand off messages via SPI to your ESP82266 module. If this isn't the answer you are looking for, please try to be clearer about it, maybe find someone to do as an English translator for you.
However, if this is what you're concerned about, and you would like to use the ESP82266 module as as standalone solution, please link its built-in processor datasheet and the relevant parts of the quadcopters code that might need debugging.
Hello I am trying to get my ESP to run a webserver that will accept a string of text an output that text through a the uart serial pins to my arduino I can't find out how to do it I would apreshiate it
My seyup would be
Arduino connected to the esp through serial pins the esp would start a server and my pc would open the webserver and type in a string of text that string would transmit to the arduino
I can't comment yet, so I'll put this in an answer :)
What I understand is you want a simple 'webserver' on your ESP, that listens to simple GET requests, takes the query string, and sends that over the serial line to your Arduino.
Firstly, are you capable of flashing new firmware to the ESP?
It's not hard, but as I understand your request, you will need to be able to do it.
Then you need to pick what would be your preferred approach:
Flash NodeMcu firmware, and expand the webserver lua example to do what you want.
Set up the Arduino IDE to work with the ESP (tutorials exist), and write a Arduino sketch to do what you want.
You could also use esp-open-sdk, or the official Espressif SDK, and write what you want in C, but since you sound like a beginner, the two previous options are likley a better choice, their easier.
I expect the NodeMcu/lua way might be the quickest, although if you're already familiar with the Arduino IDE that might be a better choice.
If there are details you are stuck on, expand your question, and I'll see if I can stick them in the answer.
I am posting this question after not getting any sort of help across the web and reading many articles and tutorials. I ended up asking questions with hope of getting guided.
DESPERATE FOR HELP.
What i want:
1) I want to build a R/C tank.
2) Basically its not controlled by a remote control but i want control by a laptop.(i could write a c++ or c# program).
What i know:
1) I know how to develop a development board. (i want to develop my own, not use arduino)
2) I know c++ and assembly very well.
3) I know about AVR's ALU, Memories(all 3), Stack, Interrupts, IO Operations well.
4) I know theory about how SPI, RS232, UART works.
PROBLEMS: (I have many questions, but most important are)
1) B/c i have made my own board. How can i transfer my program(hex file) to my board(i seek practical and physical implementation, not theory please)(i know about a 6-pin ISP but not clear about practical implementation)
2) After it, how can i make wireless communication b/w my AVR and laptop.(hardware device?)(SPI, RS232, UART?)
MAIN CONFUSION:
1) I cannot help myself differentiating or relating SPI, RS232 and UART.
I know these are used for serial communication between devices but how?(which is used when and why and how)(appropriate hardware for transmitting device and receiving device)
THING TO KNOW:
1) I haven't started making my board and programming it because i think i should learn everything first and then do it in a one go. OR should i start practical work and things get easier automatically??
2) I learnt a tutorial series on Serial Communication from http://maxembedded.com/2013/09/serial-communication-introduction/ the starting 5 topics leaving the last one(I2C). Am i missing something there?
I hope everything is clear, and waiting for a good-men's words.
Note: I am already very misguided and lost, so i want experienced and expert's guidance. Many Many Many Many Thanks in Advance.
MY BOARD LOOKS LIKE:
http://www.robotplatform.com/howto/dev_board/schematic_l/38.jpg
1) To upload your code into AVR chip, you can use ISP interface. That requires you to connect at least 5 pins: SCK, MISO, MOSI, RESET, GND, and optionally VCC (it used to control or supply voltage, but not mandatory, if your board has it's own power supply). All you need is just to wire 6- or 10-pin ISP connector to that pins of your CPU.
To begin programming process you need to obtain some programmer device (USBasp, AVRISPmk2, STK500/600 etc.), Also, you can use Arduino board itself as ISP-programmer for external AVR chip, like this: http://www.instructables.com/id/Programming-an-ATTiny13A-using-Arduino-servo-int/
Each of programmer model requires it's compatible software (such as PonyProg), for example STK500 and AVRISP programmes could be used directly from Atmel Studio.
Also, you can connect ISP to parallel (LPT) port of the PC, and upload firmware using specialized software, such as uniprof
Another way to upload software - it is to make your own bootloader - a tiny program that will update firmware, using any available interface.
2) USART, SPI, I2C - it is different interfaces to communicate with peripherals. Note that RS232 - it is electrical interface built over USART. I.e. you need external IC which will convert USART logical level signals to RS232 electrical levels.
each of that interfaces have it's own profs and cons. And usually selection of which interface to use depends on which interface is supported by peripherals.
SPI - it is interface for high-speed communication. One master many slaves. It requires a lot of wires: MISO (data from master to slave), MOSI (data from slave to master), SCK (clock) - those three could be common for all slaves. Also it requires a SS (slave select) - one SS wire for each slave to determine which slave is in communication at the moment, also it sets the edges of the data packet.
USART - it is common interface, to communicate two chips. Each byte transmitted with foregoing start bit, optional parity and following stop bit. I.e. transfer has a quarter overhead, but byte can be transmitted in any moment.
Works in synchronous and asynchronous modes. Asynchronous mode requires only 2 wires (RX and TX, not counting GND that also required). This mode requires that receiver and transmitter to be sychronized, in most cases that required to crystal oscillator to be installed.
Synchronous mode works in the same format as asynchronous, but have additional XCK (clock) wire, that determines in which moments bits are possible to be transmitted. This allows to increase transmission speed and not requires time precision from receiver. Synchronous mode is rare used.
I2C - it's a bus with only two wires, allows many masters and many slaves. Utilizes pull-up resistors to achieve wired AND, have it's own algorithm to detect collisions, more complicated to be programmed, transmission speed is limited.
Often used by peripherals, such as accelerometers, RTCs etc.
AVR chips have no it's own support for wireless communication, therefore, to do that you need to use some external wireless chip, for example bluetooth, or WiFi, there are a lot of such modules (for example ESP8266). AVR chip communicate with them using USART, sending and receiving simple commands.
The ArduinoIDE writes firmware to my Arduino UNO but I want to handle logic and code outside the microcontroller on the computer with the microcontroller strictly being a sensor and the computer handling the logic.
How can I have the computer handle the logic and listen to sensors (output data to a computer) and respond (input commands to the board)?
Is this done with serials? How do I get started with this?
I know how to code, I just need help understanding how to get the hardware to talk to one another. Arduino to computer, computer to arduino.
For example, I have a thermal sensor on the board, how can I have bi-directional communication where the output of temperature would go to a program on my computer and respond to the board to turn on an LED or other command based on statements on the computer.
All help is appreciated.
There is a tutorial on arduino.cc how to read a sensor on arduino en display the values in processing.
There is also a tutorial to turn on a led with a command from a pc.
If you want to do real complicated things I suggest that you take a look at Firmata
How can I send a string via serial communications from Java or Python? I have a very little arduino program that will recieve a CSV string of ints that each control different relays (I adapted it from their example).
I just got an Arduino, and I am trying to use it to open and close a relay remotely. I have it opening and closing the relay, no problem. But I really have no idea where to start as far as using serial communication.
I have a bluetooth dongle that I can connect to, but once I do that I'm lost.
Also, this is my first time using serial communications AND my first time using an Arduino. So I'm sorry if I am completely off on some of the things I am asking. All I know is what I've learned from Google.
Thank you very much
You can use any Java or Python serial port classes and methods. There is however one thing you need to be aware of.
The newer arduino's have a feature known as AutoReset. This works by connecting the DTR signal from the serial port to the Reset line on the chip using a capacitor or such. The IDE uses this to reset the board to activate the bootloader and initiate uploading code to the arduino. The serial monitor in the IDE is aware of this and does not toggle the DTR line when comunicating with the device (except when it initially connects).
There is are several ways to defeat this feature and you can read about them here.
As for actually comunicating with the device, there are several tutorials about serial communication in both Java and Python.
Pyserial includes the option to not use the DTR lines when opening a port.
Here is a website explaining how to use RXTX (a Java library) to comunicate with an Arduino
Best of luck.