<div dir="ltr">You can't use 5v with the PNP because the transistor will turn on when the base is more negative than the emitter (more positive for an NPN). If you connect emitter to 5V and drive it with 0 - 3.3 from the Pi, the transistor will see -1.7 to -5 (via the resistor). So it will never turn off, though if the resistor is large it will turn on less strongly when the Pi output is at 3v3.<br>
</div><div class="gmail_extra"><br><br><div class="gmail_quote">On Wed, Mar 19, 2014 at 9:02 PM, Adrian Godwin <span dir="ltr"><<a href="mailto:artgodwin@gmail.com" target="_blank">artgodwin@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">On the NPN circuit, the relay is driven from 5V. But your PNP circuit is fine if the top connection is 3v3.<br>
<br></div><div class="HOEnZb"><div class="h5"><div class="gmail_extra"><br><br><div class="gmail_quote">On Wed, Mar 19, 2014 at 9:01 PM, Adrian Godwin <span dir="ltr"><<a href="mailto:artgodwin@gmail.com" target="_blank">artgodwin@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Yes, fine if it's an electronic buzzer. If it's electromechanical then you need the diode.<br><br>
</div><div><div><div class="gmail_extra"><br><br><div class="gmail_quote">On Wed, Mar 19, 2014 at 8:58 PM, Bo Herrmannsen <span dir="ltr"><<a href="mailto:bo.herrmannsen@gmail.com" target="_blank">bo.herrmannsen@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word">been following this pic<div><br></div><div><a href="http://3.bp.blogspot.com/_c8EartLqdVs/TNQ-7InWxaI/AAAAAAAAAmo/ICttrtFaPlw/s1600/PNP+Driver.bmp" target="_blank">http://3.bp.blogspot.com/_c8EartLqdVs/TNQ-7InWxaI/AAAAAAAAAmo/ICttrtFaPlw/s1600/PNP+Driver.bmp</a></div>
<div><br></div><div>replaceing the relay coil with the buzzer and leaving out the diode</div><div><br></div><div><br><div><div><div>Den 19/03/2014 kl. 20.09 skrev Adrian Godwin:</div><br></div><div><div>
<blockquote type="cite"><div dir="ltr">I wouldn't. That buzzer takes 30mA and the pi pins are rated at 16mA.<br><br></div><div class="gmail_extra"><br><br><div class="gmail_quote">On Wed, Mar 19, 2014 at 6:52 PM, Bo Herrmannsen <span dir="ltr"><<a href="mailto:bo.herrmannsen@gmail.com" target="_blank">bo.herrmannsen@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word">I have seen guides where they attached one direct...<div><br></div><div>but of course a 3V one is needed... </div>
<div><br></div><div><a href="http://www.tandyonline.co.uk/miniature-3-3v-pcb-buzzer.html" target="_blank">http://www.tandyonline.co.uk/miniature-3-3v-pcb-buzzer.html</a></div><div><br></div><div><br></div><div><br><div><div>
Den 19/03/2014 kl. 19.17 skrev Adrian Godwin:</div><div><div><br><blockquote type="cite"><div dir="ltr">A GPIO pin won't drive a buzzer. Needs a transistor at least. <br></div><div class="gmail_extra"><br><br>
<div class="gmail_quote">On Wed, Mar 19, 2014 at 5:34 PM, Bo Herrmannsen <span dir="ltr"><<a href="mailto:bo.herrmannsen@gmail.com" target="_blank">bo.herrmannsen@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word">yeah....<div><br></div><div>a buzzer with 2 terminals cant be more simple... one terminal to gnd and one to a GPIO pin... ie pin 15 or GPIO 22</div>
<div><br></div><div><br><div><div>Den 19/03/2014 kl. 18.30 skrev Stuart Poulton:</div><div><div><br><blockquote type="cite"><p dir="ltr">I going with the keep it simple approach. </p>
<div class="gmail_quote">On 19 Mar 2014 17:25, "Bo Herrmannsen" <<a href="mailto:bo.herrmannsen@gmail.com" target="_blank">bo.herrmannsen@gmail.com</a>> wrote:<br type="attribution"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div style="word-wrap:break-word">to big.... it will not fit... its the buzzer only i need<div><br></div><div><br><div><div><div>Den 19/03/2014 kl. 17.50 skrev Stuart Poulton:</div><br><blockquote type="cite"><p dir="ltr">
How about this</p><p dir="ltr"><a href="http://shop.pimoroni.com/products/pibrella" target="_blank">http://shop.pimoroni.com/products/pibrella</a></p>
<div class="gmail_quote">On 19 Mar 2014 14:32, "Bo Herrmannsen" <<a href="mailto:bo.herrmannsen@gmail.com" target="_blank">bo.herrmannsen@gmail.com</a>> wrote:<br type="attribution"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Figured it....<br>
<br>
Now where do i find a buzzer for 3.3V that does not overload the Ras Pi's GPIO pins?<br>
<br>
<br>
<br>
Den 18/03/2014 kl. 14.14 skrev Bo Herrmannsen:<br>
<br>
> Hi<br>
><br>
> anyone that can help me out with php?<br>
><br>
><br>
> i need to replace some special danish char's with something else. This should happen no matter where they pop up.<br>
><br>
><br>
> $string = $row['delivery_street_address'];<br>
><br>
> $patterns = array();<br>
> $patterns[0] = '*å*';<br>
> $patterns[1] = '*æ*';<br>
> $patterns[2] = '*ø*';<br>
><br>
><br>
> $replacements = array();<br>
> $replacements[3] = '/x7D';<br>
> $replacements[2] = 'X';<br>
> $replacements[1] = '/x7C';<br>
><br>
> echo preg_replace($patterns, $replacements, $string);<br>
><br>
><br>
><br>
> the address in this case is: Sandkæret 1,1,1<br>
><br>
> but these 3 letters can pop up anywhere in any numbers<br>
><br>
> all help is welcome :-D<br>
><br>
><br>
<br>
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