TheBackShed.com

Forum Index : Microcontroller and PC projects : Sound From Maximite

Author

Message

johnbig

Newbie

Joined: 23/06/2011
Location: Australia
Posts: 21

Posted: 11:20pm 04 Nov 2011

Copy link to clipboard

Print this post

Hi There,
I would like to have a speaker of some sort or tranducer built into my Maximite so I can use sound for user feedback. The manual on Geoff's web site states:

"The resistors shown drop the voltage to a level suitable for an amplifier input but you can replace R6 with a link and drive a high impedance speaker or transducer."

Could someone give me an example of a high impedence speaker or transducer or any other thoughts on providing sound output.

Kind regards
John Leate

Gizmo

Admin Group

Joined: 05/06/2004
Location: Australia
Posts: 5078

Posted: 12:05am 05 Nov 2011

Copy link to clipboard

Print this post

I used a little piezo speaker in my Maximite. I think it came from a electric iron originally. http://www.thebackshed.com/Windmill/articles/Maximite.asp

Its actually pretty hard to find tiny piezo speakers in the electronic shops. Most are technically "buzzers", in that they have a built in oscillator to make the "beep" noise, and we dont want that.

But you can usually salvage piezo speakers from junked electronics, like PC motherboards, UPS's, a tweeter from a old set of PC speakers, etc. Some will be buzzers, test it with a 9v battery. If it beeps, its a buzzer, if it just goes "click!", its a speaker, and thats what you want.

Glenn

The best time to plant a tree was twenty years ago, the second best time is right now.
JAQ

ajkw
Senior Member

Joined: 29/06/2011
Location: Australia
Posts: 290

Posted: 02:46am 05 Nov 2011

Copy link to clipboard

Print this post

John,

I used this speaker. Its frequency response is ordinary but it certainly adds sound to my Maximite.

I also replaced the resister with a link to get some volume out of it.

Cheers,
Anthony.

brucepython

Regular Member

Joined: 19/06/2011
Location: Australia
Posts: 64

Posted: 08:23am 05 Nov 2011

Copy link to clipboard

Print this post

Laptop speakers are pretty compact. This one is from a retired MacBook and is driven by an LM386 mounted upside down on the veroboard. The board plugs into CON6. One day I'll do a combined board with the RTC and the audio so it can all plug into CON3 (for power) and CON6 without ugly flying leads. The speaker is thin enough to be anchored to the SD socket with some double-sided tape.

BruceEdited by brucepython 2011-11-06

sparkey

Senior Member

Joined: 15/06/2011
Location: Australia
Posts: 819

Posted: 08:41am 05 Nov 2011

Copy link to clipboard

Print this post

try places like "element 14" or "rockby" altonics and jaycar may have something "the go co" um you could try tandy but i think they have been bought out and dont even stock such devices ...try dismantling a set of head phones the type you get for free on the airlines ...that might be of some advantage ...not those tiny things but ones that have like one inch speakers in them...///...///

i dont really think that the impeadence will be that great of a problem

also i agree with what glenn had to say about a lot of pizeio drivers having an internal circuit because they are made that way so that they will produce a high pitch sound...///...///

here are a set of small cheap head phones which i have broken apart using only
a small flat blade screwdriver this speaker is very adequete...///

Edited by sparkey 2011-11-06

technicians do it with least resistance

VK6MRG

Guru

Joined: 08/06/2011
Location: Australia
Posts: 347

Posted: 10:31am 05 Nov 2011

Copy link to clipboard

Print this post

I just used an old head phone lead with the left and right channels connected together and plug it into my LCD screen which has a 3.5 stereo input for the screen's internal speakers.
This way I can mute or adjust the sound level to suit what program is running.

I cut the lead at the end where it goes into the head phone, striped the outer sheath and soldered the ground to the 0v (ground) and twisted the left and right wires together and soldered them to the sound out of con 6. I made a small hole next to the VGA connector to run the lead out of.
Edited by VK6MRG 2011-11-06

Its easier to ask forgiveness than to seek permission!

............VK6MRG.............VK3MGR............

sparkey

Senior Member

Joined: 15/06/2011
Location: Australia
Posts: 819

Posted: 11:54am 05 Nov 2011

Copy link to clipboard

Print this post

sound works with the head phone speaker...///...///also note the resistor that has been deleted as per earlier in this thread ..will increase output but i have a very low tone comming from speaker from head phone dismantled ..i have not jumperd the resistor ....///...///just yet...///...///its r"8" on the SM1 board...///...///abouve r"10"...///...///

and here i have a connector from a "P4" power supply i had to spread the pins a little wide so it would fit the connectoras well as having the speaker out of the set of head phones it works...///...///

Edited by sparkey 2011-11-07

technicians do it with least resistance

Print this page

To reply to this topic, you need to log in.