ersky9x: which speaker would smoke / be ok / be the best

Post by **bertrand35** » Sun Apr 08, 2012 7:40 pm

Hi,
For a first try I have in stock some speakers from a broken headphone. Would it be ok or would it burn ? Or worst burn my board ...
And what would be a good compromise when I will want to change?
Thanks,
Bertrand.

Post by **Rob Thomson** » Sun Apr 08, 2012 7:53 pm

I am using some headphone speakers - work perfectly

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Clivew · Post by **Clivew** » Sun Apr 08, 2012 10:01 pm

I would think most headphone speakers would be safe as they tend to be 32 ohms.
These 8 ohm speakers sound great and fit beautifully :-
http://www.ebay.co.uk/itm/1-x-MINIATURE ... 3efdea0dd3
I'm going to fit a series resistor, 10 ohms or so to be on the safe side.
Until then, I'm keeping the volume low.
It doesn't look too easy to feed the audio amp from the 5 volt rail which I would like to do!

Post by **MikeB** » Sun Apr 08, 2012 10:36 pm

The driver chip is specified for 8 ohm speakers, so 8 ohm or higher is OK.

Mike.

Clivew · Post by **Clivew** » Sun Apr 08, 2012 10:48 pm

MikeB wrote:The driver chip is specified for 8 ohm speakers, so 8 ohm or higher is OK.

Mike.

I just worry about that 3.3v regulator shutting down Mike?
I wonder if there is an easy way of feeding speaker AND haptic
off 5 volt reg. If that one shuts down, you don't crash

Clive

Post by **MikeB** » Sun Apr 08, 2012 10:57 pm

I believe SkyNorth has an answer to how to do this. I'm also discussing the 3.3V regulator power dissipation with him.

Mike.

Clivew · Post by **Clivew** » Sun Apr 08, 2012 11:00 pm

Sorry, you're on the case already,
Should have known

That little speaker is brilliant by the way!
(No commercial interest here)

SkyNorth · Post by **SkyNorth** » Mon Apr 09, 2012 12:57 am

I use a 8 Ohm , 30mm diameter speaker , hot glued in place.
The Haptic can be feed from 5V..
You cant feed the speaker from 5V , You can cut one track and run a 5 Volt jumper...let me try it first....
I'm looking at some type of heatsink for the regulator , its just real tight fit
-Brent

Post by **jhsa** » Mon Apr 09, 2012 6:42 am

i think that maybe the audio amp and anything else that takes a little more power should be using battery voltage? Not connected to any regulator that powers the MCU...

Post by **bertrand35** » Mon Apr 09, 2012 7:59 am

Brent, I understand that 8Ohms is a little bit too much for the regulator, while 32 is ok. What about 16Ohms, is there a risk, without modding the board to burn it when we will add the inflight background music from the mp3 over the SD-card?
Bertrand.

Clivew · Post by **Clivew** » Mon Apr 09, 2012 10:20 am

Audio i/c is 5.5v max, so can't be fed direct from the battery.
The 5v regulator only feeds the backlight as far as I can see,
so in the worst case and it shut down, you lose nothing vital!

SkyNorth · Post by **SkyNorth** » Mon Apr 09, 2012 11:27 am

The speaker is driven by a Bridge style of output., there is no connection to power or ground.

The best way to dissipate the heat would be a copper heatsink, that could be soldered on to the regulator tab.

You could glue a heatsink on , but with the thermal resistance through the plastic body, I dont think it will do a good job.

I'm looking at using a TO220 regulator , this can handle the heat , and is easy to attach a heatsink to. (just not as pretty)

I need to run a couple of tests as see.

-Brent

Hexperience · Post by **Hexperience** » Tue Apr 10, 2012 4:01 pm

Anyone know the ohms on a blackberry speaker?
http://www.amazon.co.uk/dp/B004U98E14/r ... B004U98E14
I have access to a dead blackberry 8330 which has haptic, speaker and blue tooth!

Wondering what I can use out of those.

Mechcondrid · Post by **Mechcondrid** » Thu Apr 12, 2012 2:53 am

wel you most likely cant use the bluetooth as thats built into the rf chip (along with wifi if i remember correctly) the haptic you may be able to use if you make a voltage divider as i believe its a 3v max motor the speaker i have no clue on i always just threw those out

gohsthb · Post by **gohsthb** » Thu Apr 12, 2012 9:49 am

The way the haptic mod is set up. You only get 3 volts to the motor. The voltage divider controls that through the transistor.
-gohst

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Mechcondrid · Post by **Mechcondrid** » Thu Apr 12, 2012 1:27 pm

ah ok didnt realize that then ya you should be able to use the blackberry motor

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