PWM output does not work

[RemiSlv]

Hi,

I am having issues with PWM controls on the REST API:

POST /GPIO/x/function/pwm returns a 403

POST /GPIO/x/pulseRatio/0.5 results in a single one period of PWM

POST /GPIO/x/pulseRatio/1 has the same effect as POST /GPIO/x/value/1

Config: RPi3 / Python 2.7.9 / rpi3-webiopi-0.7.1-deb03

The same issue was reported earlier on https://groups.google.com/forum/#!topic/webiopi/qN0RWDxPPO4

[thortex]

I was able to reproduce the problem. REST interface for pwm is not provided in v0.7.1. We should add the interface, if you would like to pwm function for GPIO.

[RemiSlv]

Hi Watanabe-san. Thank you so much for picking this up. This will be very useful to me if you find the way to fix it ! good luck

[thortex]

I've fixed the issue, and committed to master branch (as a work-around): https://github.com/thortex/rpi3-webiopi/commit/d6ea7f688c62197fdfbfc95661dc9c4b2ea8424f

Test script is also committed: https://github.com/thortex/rpi3-webiopi/blob/master/dev/test/hotaru.sh Please modify user, pass, ipadr, port, and pin parameter (line 4 through 8) for your RPi environment (e.g. An LED is wired to my RPi GPIO port no. 4). https://github.com/thortex/rpi3-webiopi/blob/master/dev/test/hotaru.sh#L8

pulseRatio and pulesAngle is already deprecated in v0.7.1. But the following REST interfaces are not provided yet: GET /GPIO/%d/pwm POST /GPIO/%d/pwm/enable POST /GPIO/%d/pwm/disable POST /GPIO/%d/pwmWrite POST /GPIO/%d/pwmWriteAngle Above interfaces may be added in the future release.

[RemiSlv]

That is great ! Confirmed it is working accordingly from my end as well. As mentioned in your test script, PWM default frequency is 50Hz.

Is there a method to change it ? I can't figure this out easily from the code. I'm using it to control LEDs so I'd like to change that to 100Hz or so to reduce the flickering effect :)

Other than that, this issue can be closed !

Thanks :+1:

[thortex]

I added pulse frequency setting interface to REST. Please test with /dev/test/ directory scripts: https://github.com/thortex/rpi3-webiopi/blob/master/dev/test/

maximum frequency is 100.0 Hz, but 100.0 Hz is not recommended for ordinary use.

./hotaru.sh 100

In case of 50 Hz:

./hotaru.sh 50

In case of three seconds blinking at 1 Hz:

./min-pulse.sh 1 3

In case of three seconds blinking at 2 Hz:

./min-pulse.sh 2 3 

In case of two seconds blinking at 10 Hz:

./min-pulse.sh 10 2

In case of twice sos signals for emergency (sleep timing should be optimized for your CPU frequency):

./sos.sh

Usage restriction is listed below:

• First, set GPIO pin function to PWM, then set pulse frequency, Finally set pulse ratio.
• For blinking, pulse frequency can be set to less than 25 Hz.
• For dimmer, pulse frequency can be set to more than 30 Hz.
• Does not work at less than 1 Hz.

[RemiSlv]

This is excellent, thank you so much again. I'm all set now, you've been a great help !

Just out of curiosity, may I know why 100Hz is not a recommended value ?

[thortex]

Please refer to WebIOPi forum in Google Groups: https://groups.google.com/forum/#!topic/webiopi/qN0RWDxPPO4

[RemiSlv]

thanks, I am closing this issue now

[thortex]

Thank you for your issue reporting, and closing. Please feel free to ask me, if yo have any questions, ideas, or improvements.