Volume control PI in Node-Red

[Peter Scargill]

I wonder if anyone here is a step ahead of me.  In the THINGBOX is a VOLUME node (which I could not get to work) - so back in the world of ordinary Node-Red - has anyone come up with a Node-Red node which will allow control of the PI volume... would be useful as I've done a speech flow using mpg123 and ivonatts - and in my latest installation it's a tad quiet - of course you can go into Linux but it would be so much better if you could prefix - say an alarm sound with high volume or general speech with low volume..

Any takers?

[Nathanaël Lécaudé]

You can control the volume of the ALSA mixer using an exec node in Node-RED with this command:

amixer --quiet -c 1 set Digital VOLUME

Where Digital is the name of the parameter you want to control and VOLUME is the value. 

[Peter Scargill]

I tried that (Raspberry Pi 2 running Wheezy playing an MP3 file) with a space after the word Digital (I am using the 3.5mm connector for audio) and different values as parameter passed by an inject node. Made no difference at all ???

 

Pete.

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[Peter Scargill]

Thanks for that – you started me off

amixer cset numid=1 --

 

That did the job with 100% stuck on the end  - a little sub-node I think as 40% is almost silent.. Got it – great.

 

From: node...@googlegroups.com [mailto:node...@googlegroups.com] On Behalf Of Nathanaël Lécaudé
Sent: 05 January 2016 15:38
To: Node-RED <node...@googlegroups.com>
Subject: [node-red] Re: Volume control PI in Node-Red

 

You can control the volume of the ALSA mixer using an exec node in Node-RED with this command:

--

[Nathanaël Lécaudé]

This also works:

[{"id":"45776f8a.ba889","type":"ui_tab","z":"e17f5ace.1e80a8","name":"Home","icon":"dashboard","order":"1"},{"id":"7b75ca20.848a34","type":"ui_slider","z":"e17f5ace.1e80a8","tab":"45776f8a.ba889","name":"Slider","topic":"","group":"","order":1,"min":0,"max":"100","x":130,"y":200,"wires":[["c871e3ff.378e2"]]},{"id":"3058a916.cfa756","type":"exec","z":"e17f5ace.1e80a8","command":"amixer set PCM","addpay":true,"append":"","useSpawn":"","name":"","x":438.5,"y":200,"wires":[[],[],[]]},{"id":"c871e3ff.378e2","type":"function","z":"e17f5ace.1e80a8","name":"","func":"msg.payload = msg.payload + \"%\";\nreturn msg;","outputs":1,"noerr":0,"x":270,"y":200,"wires":[["3058a916.cfa756"]]}]

[Peter Scargill]

I was so pleased the numid thing worked I did a little blog item – I’ll try yours now – thanks! http://tech.scargill.net/raspberry-pi-volume-in-node-red/

[maxime....@digitalairways.com]

Hello Peter,

The volume node from thethingbox works as you do on your blog post.
Here an example with this node:

[{"id":"45776f8a.ba889","type":"ui_tab","z":"e17f5ace.1e80a8","name":"Home","icon":"dashboard","order":"1"},{"id":"7b75ca20.848a34","type":"ui_slider","z":"e17f5ace.1e80a8","tab":"45776f8a.ba889","name":"Slider","topic":"","group":"","order":1,"min":0,"max":"100","x":130,"y":200,"wires":[["c871e3ff.378e2"]]},{"id":"3058a916.cfa756","type":"exec","z":"e17f5ace.1e80a8","command":"amixer set PCM","addpay":true,"append":"","useSpawn":"","name":"","x":438.5,"y":200,"wires":[[],[],[]]},{"id":"c871e3ff.378e2","type":"function","z":"e17f5ace.1e80a8","name":"","func":"msg.payload = msg.payload + \"%\";\nreturn msg;","outputs":1,"noerr":0,"x":270,"y":200,"wires":[["3058a916.cfa756"]]}]

If you any troubles with it, please tell me, I can help you.

Maxime
TheThingBox Team

[Peter Scargill]

Thanks for that.  I found my modification necessary as for some reason all the volume seems to be concentrated at one end of the scale. Good idea to use the slider from UI

 

Pete.