Just type ls /dev/tty{USB,ACM}*
in the console at the bottom of the IDE. That should display most USB connected UART devices
PS: if you want to connect to the board via SSH instead, use ssh root@bela.local
How do I make Bela receive serial communication from arduino within pure data?
Hello! I stumbled upon this thread because I try to do something similar. I got it to run the way you described with the above pd sketch and render.cpp. I am sending a series of floats as text, separated by space and ending with a newline character. It works somehow but also it seems there are numbers getting lost on the way. I am sending ten numbers (changed the unpack and pack accordingly) but I get sometimes 5, sometimes 7, sometimes ten and also they seem to get mixed up. I tried to reduce the frequency in which the Arduino sends but even at once per second it happens. Any ideas why? Thanks in advance!
I also tried to send the numbers as bytes (I mapped it to 0-255 so one byte per number because it doesn't really matter whether I get the actual values for me) and changed "newline" to "none" but then I got only zeroes ...
I have made some improvements to the SERIAL features in the past months and I just pushed a simpler but better documented example (PureData/serial). So make sure you get the latest dev
branch of Bela on your board and that you remove any .cpp file from your Pd project, then try again and come back if you still have trouble.
Among the new features, you can now set bytes
as the type and receive individual bytes as a value between 0 and 255.
Thank you very much! I tried and it seems to work now.
- Edited
giuliomoro Hi! I'm trying to make sense of Serial reading into PureData, and I can find " a simpler but better documented example (PureData/serial)". I've got the lastest dev branch of Bela on my board. Any advise?
I'm trying to send data from arduino to PureData running on Bela, i'm running the PD patch that is shared upper, and printing the values. Even though they look good on Arduino Serial Monitor, In Bela its strange, I'm not receiving every values, and it's changing variables order. I was trying to look for the example that you wrote about.
Sorry if this is a simple question that i'm not getting, and thank you!
This is the example: https://github.com/BelaPlatform/Bela/tree/dev/examples/PureData/serial
If it's not on your board, then it's likely that you are not actually running the latest dev
branch. From the IDE go to settings -> other system functions -> version info and report what you see there.
- Edited
giuliomoro , hmmm i'm still trying to make sense of "running the latest dev branch". I know i've updated Bela recently.
Ok, just got to the instructions on hwo to update to experimental release, and i'm updating to the dev branch right now!
This is was what i got on my version info:
This is after updating to dev branch:
And there is it! Thank you!
Unfortunately i'm getting inconsistent readings more than 5 variables.. Until 5 variables, i get the values print on Bela console right. With 6 variables values start jumping in a strange way.
On the Arduino:
Serial.print(gY, 0);
Serial.print(" ");
Serial.print(gZ, 0);
Serial.print(" ");
Serial.print(val_bme_temp, 0);
Serial.print(" ");
Serial.print(val_bme_alti, 0);
Serial.print(" ");
Serial.print(val_bme_humi, 0);
Serial.print(" ");
Serial.println(val_peso, 0);
Thank you again ;_;
Hey, I cant send more that 4 variable values, any suggestion? Thank you!
sergio_coutinho With 6 variables values start jumping in a strange way.
Can you say more about this? I am wondering if what's happening is that the data is received and passed to Pd just fine and the issue is only with the printing
giuliomoro hey,
Arduino:
Serial.print(aX, 0);
Serial.print(" ");
Serial.print(aY, 2);
Serial.print(" ");
Serial.print(aZ, 2);
Serial.print(" ");
Serial.print(aSqrt, 2);
Serial.print(" ");
Serial.print(gX, 0);
Serial.print(" ");
Serial.print(gY, 0);
Serial.print(" ");
Serial.print(gZ, 0);
Serial.print(" ");
Serial.print(val_bme_temp, 0);
Serial.print(" ");
Serial.print(val_bme_press, 0);
Serial.print(" ");
Serial.print(val_bme_alti, 0);
Serial.print(" ");
Serial.print(val_bme_humi, 0);
Serial.print(" ");
Serial.print(val_peso, 0);
Serial.print("\n");
delay(200);
and in Bela PureData, i've tried multiple prints, but the ones that should work:
Inconsistent readings, at least printing:
nothing shows on the last unpacked float, and the first ones are inconsistent (like the console printed values)
Thank you for your help again!
ok there was a bug in the code handling that. Try creating a new render.cpp file in your Pd project and paste the content of this one into it, then rebuild the project and try again: https://raw.githubusercontent.com/BelaPlatform/Bela/dev/core/default_libpd_render.cpp
giuliomoro It works! Thank you!
With this render file i have no problem in unpack all variables coming from serial!
- Edited
ok thanks that's available for everyone on the dev branch now. If you update your board to that, you will no longer need the cpp file in the project and the update will apply across all projects.
giuliomoro thanks
What if I don't want to connect via the USB cable, but instead via the Arduino Tx and Rx pins? Could I connect those pins (with a logic level shifter?) to the Bela somehow and have at least one-way serial communication from the Arduino to PD on the Bela? Which pins would I use in the Bela? And how would I define the serial port in PD?
- Edited
Yes that's doable. On the software side, the latest dev
branch of the Bela core code contains example PureData/uart-communication
. Make sure you update your board to the latest dev
branch following the instructions here.
Hardware-wise, if your Arduino has 3.3V signal levels, then you can connect the two directly. If your Arduino has 5V signal levels, on the other hand, you need some way of adapting that voltage to Bela's 3.3V. A dedicate logic level shifter IC would be the ideal solution, but you could toy around with a passive one, too. Remember that Bela cannot take unbound current from 5V sources into its pins, so protection is needed.
For 5V Arduino -> 3.3V Bela you could try something like this:
Arduino
Tx---+
|
R1 4k7
| Bela
+-----------Rx
|
R2 8k2
|
GND
R1 and R2 is the resistor divider with gain R2/(R1+R2) and R1's high value doubles up as a current limiter. Values are not critical, but keep R1 > 1k and pick R2 so that R2/(R1+R2) * 5V is between 2.7V and 3.3V.
Passive level shifting to go from Bela's Tx at 3.3V to Arduino's Rx at 5V is not possible, but it may be that there is no need for level shifting: the ATMEGA328p's datasheet states in table 28.2 "DC CHARACTERISTICS" that an input can be registered as HIGH if it's as low as 0.6Vcc, i.e.: 0.65 = 3.0V. So it may just work with a direct connection. However, I'd add some protection to avoid burning Bela in case the Arduino pin sends out 5V at some point, either during boot or because of a but in the fw. Put 10k in series and that should be more than enough.
giuliomoro
Hi! Just to know: if we update Bela Board from IDE (or other ways) - at present 8h - do we get this update of render.cpp for serial communication or we need to getting it by hand?
If you update to the dev
branch, then it's already there.