X-Authentication-Warning: delorie.com: mail set sender to geda-user-bounces using -f X-Recipient: geda-user AT delorie DOT com X-Original-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=rIynEno0kAkwH8/nerMILjRl23t3iELTBLqdtu/uIVE=; b=dopSArlae65jVpfG+EdTNOIXu9ud2/S1rnrbx7RU7fkYpJb8r4Y+0Kry2d0xzFLYqX jRFMp5Xo8WPGSi/5BzpfAXhrpaENUDC8I0uozCGN/ZH9/7ETh2THNGdeCJuagur4BYeM kXA82+yvLbfoHs04SXrrfyW9/kCNCLcupAeE914W0VgWStszEve9FzwBA9m/ZZkWQ4Mk j05lS8mT9KY9WSLJJCdLZxFKy9WtGXjuHZg2gw/N/hyvA2V/XFrttjj31Cxq14hPh0CM E6mlDhLo9OSn5BnD9FKSYsvTH2LHBNZaxqQfMRPxauqIgdlnOauaoZQGih4TRopwz8A3 6iXA== MIME-Version: 1.0 X-Received: by 10.152.243.9 with SMTP id wu9mr14642752lac.41.1440363419036; Sun, 23 Aug 2015 13:56:59 -0700 (PDT) In-Reply-To: <1508231827.AA21909@ivan.Harhan.ORG> References: <1508231827 DOT AA21909 AT ivan DOT Harhan DOT ORG> Date: Sun, 23 Aug 2015 20:56:58 +0000 Message-ID: Subject: Re: [geda-user] Microphone footprint woes From: "Evan Foss (evanfoss AT gmail DOT com) [via geda-user AT delorie DOT com]" To: geda-user AT delorie DOT com Content-Type: text/plain; charset=UTF-8 Reply-To: geda-user AT delorie DOT com Errors-To: nobody AT delorie DOT com X-Mailing-List: geda-user AT delorie DOT com X-Unsubscribes-To: listserv AT delorie DOT com Precedence: bulk On Sun, Aug 23, 2015 at 6:27 PM, Spacefalcon the Outlaw wrote: > Richard Rasker (rasker AT linetec DOT nl) wrote: > >> Correct me if I'm wrong, but I don't think that this is an SMD part, and >> that you're supposed to simply solder wires to the contacts. >> >> For SMD type microphones, search for "MEMS Microphone", e.g. >> SPW2430HR5H-B from Knowles. > > Thank you for shining the light on my ignorance! As I have just > learned, the type of microphones I've been looking at are called > electret condenser: they are the type that's been used in the > old-fashioned cellphones of the early 2000s, they are what the GSM > chipset I'm using has been designed to work with, and I don't feel > like changing to MEMS - my motto in this project is Do Not Innovate. > > And I also just learned why ECMs are generally not made in SMT form > factor: they can't withstand the heat of reflow soldering. This part > certainly explains why most cellphones I've examined have their > microphone on wires or on a little strip of flex whose other end is > hotbar-soldered to the main PCBA, and very few of these old phones > have their microphone directly on the main PCBA. As for the few > phones that did the latter (Openmoko GTA02 and Pirelli DP-L10 do that, > which is where I got my naive idea of doing the same), it looks like > there were some very few electret condenser microphones made in SMT > form, but they are now "obsolete" and unobtainium. A lot of the MEMS microphones are a pain to prototype with because of their footprints. That said they are massively better than electret condenser. > My solution: I'll put a two-pin header on my board instead of the > microphone part, and make the actual microphone a post-board addition. > The same as I already did with the loudspeaker. Can I suggest that you add a couple extra pins for power and gnd so that if you change your mind you can? > Thanks again for the education, > SF -- Home http://evanfoss.googlepages.com/ Work http://forge.abcd.harvard.edu/gf/project/epl_engineering/wiki/