Let's Make Robots!

Getting SOUND from your Picaxe (Works with other controllers also).

WARNING:  If "techie-stuff" makes your head hurt, do not read the following. 

      (ha ha)

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To make sound from your picaxe, the manual shows a 10 uF capacitor in series with a 40 ohm speaker.

This will work but gives a very low volume sound.

Now, 10 uF would be 16 ohms reactance at 1000 Hz and less at higher frequencies. So for high pitched tones, the current draw from the picaxe would mostly be limited by the 40 ohms of the speaker and could approach (5v / 40 ohms =) 125 mA.  This concerns me because the current drain on any picaxe lead is supposed to be no more than 20 mA.  Now admittedly the audio component will be a fluctuating or intermittant value, so it is probably okay.

However, this will still be a very low volume sound.  If you are like me you want it to be louder. So some amplification is needed.  Consequently, I have drawn up a couple variations of fairly simple audio amps to use with the picaxe to give more volume but lower the current drawn from the picaxe.

The following are not intended to be high quality audio amplifiers, but rather have been drawn for simplicity of construction, using a few commonly available parts.

 

 

 

AttachmentSize
Audio-Amps-1-for-Picaxe.jpg204.9 KB
Audio-Amps-2-for-Picaxe.jpg153.32 KB
BIGGER-Audio-Amps-1-for-Picaxe.jpg394.32 KB
BIGGER-Audio-Amps-2-for-Picaxe.jpg321.32 KB

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Ouch. My eyes hurt. 

Please attach larger versions of the files. Then you can link the inline versions to the larger versions, so I can just click and get the big picture. Do it for me. Think of the pupils! The straining cornia! The bloodshot capilaries! Oh! The humanity!

Far be it from me to want to be found guilty of stressing a capillary, so try these attachments I just added.

Oh, so much better. Thanks.

If you want full marks, edit your post and select each inline image. Then click the 'Insert/edit link' button and paste in the URL for the relevant picture. bOd

I tried that but could not make it work. I tried both the url from my uploads page and the one from this page, below the text. Neither worked. When I clicked Insert, the url just goes away. I tried filling in the other three lines too, but nothing.

 

Some time ago, I had this problem with Google Chrome browser. I had to use IE just to add the links. But after an update, it works properly now. So, try other browsers, it's just a glitch in the matrix...

Works for me. See below.

Yep, after trying it MANY times, the top one now has the link using Firefox, but the second one still won't take it. (Firefox keeps logging me off of LMR when I try to update the link.) I log in and try again and it worked one time.  IE won't take the links at all.

 --probably something about my internet settings, I suppose.

 

In IE, I get     "This content has been modified by another user, changes cannot be saved."

 

ADDED:  FINALLY.  I must have tried it 50 times...  It finally took the other one using Internet Exploder, and using .png versions of the drawings.