I came across this website when trying to find a reliable way to use the watchdog for preventing failures (code lock ups) and saving battery using an Arduino.
I tried the code and it worked fine. However, i would also like to use the serial monitor. I tried adding Serial.begin(9600); in the setup, however, most of what is shown in the serial monitor (from the code within the main loop) are strange characters (the baud rate is set to 9600). Is this something to do with the function to configure the wdt and the placement of Serial.begin(9600) in the code?
I'd also like to use an external interrupt (via a button on Digital pin 3) to wake the board from sleep. How can be achieved based on the current code? I know how to implement using a different method of making the board go to sleep without using any watchdog at all, however, i have been unsuccessful in making it work with this code.
Many thanks for any help.
As said above, the serial communication should work fine. Are you sure you are able to make your serial communication work fine without the watchdog part of the code? I have used the watchdog tips given on the website along with serial communications without any problem on Arduino Uno, so I would guess the serial communication problem lies somewhere else in your code.
Can you write a bare bone example of your code with the watchdog management part, a serial communication or two somewhere in your loop(), and if you want some delays / infinite loops to test the watchdog firing, post it here, test it on your board and indicate if / where you have problems?
I have never used a pin interrupt, but it seems that google gives some nice results with example code. Have you tried the results given by google?
https://www.arduino.cc/en/Reference/AttachInterrupt
http://www.allaboutcircuits.com/technical-articles/using-interrupts-on-arduino/
You will have to be careful regarding the choice of the pin on which you put the interrupt, as explained in the Arduino Reference only pins 2 and 3 support interrupt on the Uno.
Related
I've been trying to establish serial (UART) communication between a Raspberry Pi Model B Revision 2.0 (checked the model like described on this page) and Arduino Mega 2560. I made a service on the Pi that writes to UART and then expects a message and a coworker programmed the Arduino with an echo program. While they were communicating, I had trouble receiving data, meaning that it was clustered in 8 byte pieces and I had to introduce a timeout for waiting between them (I was actually as much as available and calling select()for the next cluster but it turned to be 8bytes a cluster, except for maybe the last one. As explained in a question I found on this site, the programmer is the one to take care of the protocol and can not rely that the whole message will be ready to read at once (that is logical).
However, when I just connected Pi's TXD and RXD pins, no matter how much bytes I tried sending, it sends them in one go (I've gone up to a bit more than 256, that's more than enough for my purposes). I also have around 50 milliseconds of duration difference, measured directly from within the program, using gettimeofday() function.
So, could anybody clear things for me:
Why is this happening?
Is this difference in behaviour expected?
Is there a potential problem in either of the devices (if that can even be concluded from the given information).
Of course, any additional information is welcome, in case I forgot asking something that is deemed important.
Why is this happening?
I tried some time back communicating Arduino-Arduino and Arduino-Pi. I faced some problems with UART communication. However, you might want to keep same Baud rate on both the devices. With Pi, you might need to trigger an event if you receive data from Arduino. On the other side, if you code runs longer, then you might lose some data i.e. your Arduino code is running something else while Pi sends data over UART.
Is this difference in behaviour expected?
Yes. Arduino is a microcontroller based device while Pi is microprocessor based (runs on OS)
Is there a potential problem in either of the devices (if that can even be concluded from the given information).
I don't think there could be any hardware problem unless it is not functioning at all.
Also, because of this issues, I switched from UART communication to SPI communication. This solved my problem completely.
I am using 2 esp8266 wireless modules to establish bidirectional wireless communication between 2 arduino boards (one mega and one uno) without the use of any earth based technologies (i.e. radio frequencies, wifi which relies on earth sattelites, etc.). My solution was to use the esp8266 to establish a private area network with both esp's acting as a station and an access point (AT+CIPMODE=3). Unfortunately, this solution has proven to be more of a hassle than it was worth.
To start, I have the esp's each wired according to this diagram
When I first started out, the red LED was on and the blue LED was off. During this time, I was able to send AT commands, establish the server, and achieve the communication I required by entering commands directly to the serial monitor. After this, I started writing a library using the SoftwareSerial library to allow me to issue commands directly through the program to set up the esp as needed upon start up of my script. Before doing this, I changed the baudrate to make sure it was running at 9600, and entered the AT commands in the serial monitor to make sure everything was working properly and it still worked.
After I began writing the library, before uploading the code with a test of the library I noticed the blue LED was lit solid now. Noticing this, I reuploaded the barebones script (I haven't uploaded the library code to the arduino yet) and the esp was no longer receiving the AT commands.
Does this indicate an issue with the board which I can fix or does this mean the board is done?
With my deadlines approaching fast in about 3 weeks it is crucial I get this wireless communication working so if this is an issue with the board, I'm going to have to scrap the esp's and use a different way of communicating. So my second question is, if this is the case, what are other viable options for establishing this communication? I have used xbee's before and while that would be ideal, they fall out of the budget I have been alotted so I need to keep it under $50 for this. If bidirectional communication is not possible for that price I can live with one way because I just need to get this system working. Basically I just need to transmit a single byte of data.
I realize this response is a little belated, and I hope you got it sorted: I've started working with the ESP8266 myself in the last few weeks, and hence why I was looking around for tutorials on direct communication between 2 units, when I found your post.
From what I've been able to ascertain, the AT commands are a part of the 'firmware' which ships with some modules. The Arduino code however starts loading onto the chips at memory address 0x0000, which is the same address that the firmware update tools use.
In other words, I believe that with the Arduino-coded program running on there, you lose the AT command functionality.
If you find a firmware update tool for the ESP8266 (plenty online) you'll get back the AT commands.
I suppose though the real question is why would you want to? It seems that the AT commands are just a way to treat the ESP as a dumb WiFi antenna. With the Arduino code, you're actually treating it as a micro-controller in its own right.
I have an Arduino Uno and I am using arduino 1.0.5 IDE. I followed he procedures for bootloading an atmega328P-PU on a breadboard.
I uploaded the ArduinoISP sketch first, made the connections(using the External Oscillator) and then wired it up. Then, I selected the programmer as Arduino as ISP, selected the board as Arduino duemilanove w/ Atmega328P. Then I selected the correct serial port and clicked Burn Bootloader.
I got the following errors:
avrdude.exe: stk500_program_enable(): protocol error, expect=0x14,
resp=0x50avrdude.exe: initialization failed, rc=-1 Double
check connections and try again, or use -F to override
this check.avrdude.exe: stk500_disable(): protocol error, expect=0x14,
resp=0x51
How to solve this issue? Also, can I upload the bootloader directly by using it on the Uno in place of the original chip. If so, how?
to my understanding the error you have indicates a bad reading from the chip. I experienced that with chips that were either dead or not properly connected, especially to power supply.
You may find more detailed information in th tutorial : https://www.arduino.cc/en/Tutorial/ArduinoISP
Especially those things :
Note for Arduino 1.0: you need to make one small change to the
ArduinoISP code. Find the line in the heartbeat() function that says
"delay(40);" and change it to "delay(20);".
Select the items in the
Tools > Board and Serial Port menus that correspond to the board you
are using as the programmer (not the board being programmed).
Instead of arduino built-in boot loader just go through below link and it will be great for uploading boot loader and verifying board status info
I am replying you this because same issue I got long back and it saved me.
One more thing for arduino boot loader: for atmega328 you need to put capacitor between reset and gnd( in case you missed)
For gammon bootloader you don't need it.
Be Innovative.
For reset line you might me using 100nf(thats what stated in documentation )...but sometimes it doesn't work...try something like 4.7uf, 22uf or 47uf or close values
I had a similar problem and the issue was that my programmer was a bit slow, I used the -B flag for avrdude to slow down the bitrate and it started working, I set the -B20 and works like a charm every time, but I use the USBTinyISP programmer, not the stk500 one, so this might not work for you.
In case someone stuck at this as I did and nothing like changing the cap value helped. Make sure you are using your USB-TTL adapter in a 5v mode (obviously for a 5v powered chip). I always used it in a 3.3v mode in order not to accidentally burn my 3.3v chips and it always worked. Until today, I was trying to flash my custom atmega8 board and everything worked with the ISP but I was having a hard time using the bootloader and after half a day searching and trying different stuff the 5v setting to the rescue.
I am using Arduino Uno R3 with the SIM900A for a couple of weeks. The problem I'm facing is, everytime I make a call from a Nokia (or anyother) cellphone to SIM900A - I see just one RING as unsolicited result code on the Serial Monitor and I cannot hear any rings going on in Nokia. Everything is blank for about 5 seconds and then the call attempt drops.
Why is this happening? Do I need to execute some AT Command as soon as a RING happens, to show Calling Cellphone that the ME is ALERTING/RINGING ? Also, when I call once to SIM900, should I not see many "RING" instead of once?
Finally, I found out what was wrong. External Power Supply!
Turns out the SIM900A board was not getting enough current to function properly. When I connected the Arduino Board to 12V external power Supply (2Amps), it worked like a charm!
Try it out, it really works! :)
I am developing a project to monitor solar voltage and battery voltage by displaying them on an LCD. I programmed an Atmega8 with an arduino. When I attached the LCD with the board it worked pretty well. So I detached it from board and made a breadboard circuit as described on this page.
It didn't work this time. I checked all the connections many times but could not get to any point. Kindly guide me how to make a standalone atmega8 circuit to display something on an LCD.
Start slowly. There are some pitfalls when migrating to your own design (and yes, there's another forum for that). If you're using an external crystal oscillator, make sure that you've programmed the Atmel chip to use it by programming the appropriate fuse bits. After that, look to see if you can toggle a single output of the device. Ideally with a single LED connected, so you can see if the output port is changing state.
Some LCD controllers can require relatively precise timings, so if you have a logic analyser you can examine the waveforms. Otherwise, check your clock timing by turning on and off an LED every ten seconds (or so) and use a stopwatch to count ten or twenty of the LED flashes. You can see what your clock speed is working out to be, and verify that it's the right clock, etc.
You need to program the fuses correectly for standalone operation when no crystal is attached (Arduino has an external crystal) Hence, for running an Atmel using the internal clock, the clock fuse needs to be programmed correctly. In the datasheet you will find the description.