noob question: I'm trying to interface directly through read/writes to the file system. I got an motor running (yay!) like a lightweight EV3LargeRegulatedMotor. Now I'm trying to get an EV3 Ultrasonic Sensor running, but I'm not sure of the "startup" sequence. I think I have to write the right device to the right port...
Oh and random follow-up question. For stuff like "state" I noticed virtual file system updates the contents of the file, but not the modified date or size. Which makes me doubt I can use Java's WatchService to know when the state or speed changes. But I'm not sure. And if it would be better than rapid-polling the file, I'm all for a better way!
poll as in https://docs.oracle.com/javase/7/docs/api/java/nio/file/WatchService.html#poll() ? That is great!
I will try both these. Thank you again!
Reporting back: nope, https://docs.oracle.com/javase/tutorial/essential/io/notification.html does not notice when a motor's "position" file changes.
Thanks!
What are you trying to control?
just driving standard tricycle robot for line following
I have the basic P controller example from github
then you just have to come up with a function to convert the sensor value to a speed and angle
and it does the rest to adjust the speed of the motors
thanks!
Have a look at https://github.com/KWSmit/KSmEV3TicTacToe--PiStorms-version-, I think this will help you...
@KWSmit Cool project! And thank you for your code, i am able to do a simple Motor sanity check. I understand why i got that Device Not Connected or not found error. I was trying to step into the code and there is no device "simulator" sort of environment or library on the VS Code. How do you usually do debugging? print() statements or any special configs to step through the code in real-time?
@fadleensidek Just logging and sometimes the interactive terminal is handy (https://www.ev3dev.org/news/2020/02/13/ev3dev-vscode-extension-beta/).
And with RPi you can also do remote bugging from VS Code (https://code.visualstudio.com/docs/remote/ssh). Haven’t used it myself yet, though...
I can confirm, @KWSmit and @fadleensidek that remote debugging from vscode works beautifully on the RPI. I use it all the time... and even in containers which is kind of nice but trickier to install. There is even for simplicity this thing called codespaces which is a vscode server running on the RPI. That part I've not tried it. It's a bit more involved because it requires access to the internet from the pi, and Azure credentials, so it might not be the easiest thing to do. But it behaves more or less the same as vscode remote.
@omartin2010 and @KWSmit yes, i would like a more "typical" sort of debugging where i can put breakpoints and watches. Debugging using logging and print are just too troublesome imho. The interactive terminal is useful for stack traces too as mentioned by Kees. Not really sure why the
mtr.motor.wait_until_not_moving() function is not a blocking function when in the docs it says it is..Maybe i am missing something. No wonder Kees implemented his own wait function in his project calledwait_while_motors_running(). Since i just got my PiStorms a couple of days back, still got a lot of reading and trying to do.. I will read up the remote debugging technique as mentioned by @KWSmit and @omartin2010 . thank you.
@fadleensidek you’re right that the wait-functions don’t work on the PiStorms. I believe it has something to do with the PiStorms firmware. Maybe @dlech can elaborate more on this. You’ll also find out that the motors show a kind of ‘jittering’ behaviour, especially with
hold and brake. This are the only two disadvantages of PiStorms.
@KWSmit have not explored too much of the APIs but since i am able to do remote debugging now, things can proceed better. Probably will need to wait until the weekend to find the time to play around further. wait_while_motors_running, the wait functions and the stop actions such as hold and brake are working fine in the EV3 block? I only have the PiStorms. Btw, I tried using the motor.is_running flag to implement a custom wait.. Seems like the flag will need at least 4 to 5 ms "response time" to toggle but it can be a hit or a miss at those timings. 10ms is much safer.
I'm trying out ev3dev java, but I'm having trouble with tests of the gyro sensor. On the LCD screen when watching the values, the angle gets reported correctly in both the positive and negative direction. But when I run any of the three gyro demos (with logging of the gyro values) only positive values are being logged. Any negative values get logged as 0. I'm using the this [demo] (https://github.com/ev3dev-lang-java/examples/blob/master/ev3dev-lang-java/src/main/java/ev3dev/sensors/ev3/GyroSensorDemo3.java) can anyone help me understand why I'm not getting negative values from the gyro sensor?
Well, I know this is probably the wrong forum, but I just found out that Ev3G for Mac is EOL (being only 32-bit). Does anyone know the future of the EV3 Home Edition? @dlech thanks for the help over the last month. I was able to teach a class to rising high school students using MicroPython and VSCode. I introduced them to a number of concepts, including ... Python, networking (wifi for all the robots), ssh, Linux and VSCode. Pretty cool time.
there is a new scratch-based programming software for macOS from LEGO