X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from wr-out-0506.google.com ([64.233.184.225] verified) by logan.com (CommuniGate Pro SMTP 5.1c.2) with ESMTP id 1221660 for flyrotary@lancaironline.net; Sun, 02 Jul 2006 22:02:31 -0400 Received-SPF: pass receiver=logan.com; client-ip=64.233.184.225; envelope-from=russell.duffy@gmail.com Received: by wr-out-0506.google.com with SMTP id 68so624659wra for ; Sun, 02 Jul 2006 19:01:48 -0700 (PDT) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:from:to:subject:date:message-id:mime-version:content-type:x-priority:x-msmail-priority:x-mailer:importance:in-reply-to:x-mimeole; b=BcHeIGuPo/8Cd7UPwxLSHGayJWDrrR6FFWNeeHvNUUKjVmxI/f/OKNIYYQfVyQKJMrF9EqyJJfkWxpoo1u+vLK3DAY1PZeaGv712A/tZFxR66bq/4DwsH2MHfBtRnTTnjn0GeIYdCanAqIgW3G+KaNK/N6/zXvx1wj6vEB9joUU= Received: by 10.54.69.13 with SMTP id r13mr1102291wra; Sun, 02 Jul 2006 19:01:48 -0700 (PDT) Return-Path: Received: from rd ( [65.6.194.9]) by mx.gmail.com with ESMTP id 38sm1695685wrl.2006.07.02.19.01.46; Sun, 02 Jul 2006 19:01:47 -0700 (PDT) From: "Russell Duffy" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] EM-2 question for Tracy Date: Sun, 2 Jul 2006 21:01:47 -0500 Message-ID: <000001c69e44$a4ea6fb0$6101a8c0@rd> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C69E1A.BC16D8B0" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 Importance: Normal In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2869 This is a multi-part message in MIME format. ------=_NextPart_000_0001_01C69E1A.BC16D8B0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable I have an LED (designed for 12V) wired up for the alarm light, and it = comes on (not flashing, steady) at what seems to be about half brightness when power is applied to the EM-2. =20 =20 Hi Bill, =20 I had the exact same problem with the current EM-2 (all in one), but not with the earlier one (separate electronics box). In both cases, I used = the exact same super bright LED's from the Shack of Rat. =20 =20 In talking to Tracy, my understanding is that the alarm signal pin is on = a 5V pull up, with a 10k ohm resistor. When the EM-2 wants the light on, = it grounds the pin, but when it's "off", the pin would be sitting at 5V. = If you tie the light to 12V, then there's a 7V potential across the light, = with a 10k ohm resistor in series. This will allow some current to flow, and would probably not be noticeable on an incandescent lamp, but for LED's, = it will appear to be on, but dim. =20 =20 The fix was to use one of the EM-2 5V outputs for the LED alarm light = power. This gives no voltage differential when the light is supposed to be off, = and 5V differential when on. =20 =20 If you are using a pre-packaged LED that's made for 12V, and you use 5V instead, it will work but will be dimmer than it would have been with = 12V. You may have to use a different LED. =20 =20 Tracy may also have a better answer now, so stand by for the real answer = :-) =20 Cheers, Rusty (single rotor engine currently installed on the hanger floor) ------=_NextPart_000_0001_01C69E1A.BC16D8B0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Message
I have an LED (designed for 12V) =  wired=20 up for the alarm light, and it comes on (not flashing, steady) at what = seems to=20 be about half brightness when power is applied to the EM-2.  
 
Hi=20 Bill,
 
I had=20 the exact same problem with the current EM-2 (all in one), but not with = the=20 earlier one (separate electronics box).  In both cases, I used the = exact=20 same super bright LED's from the Shack of Rat. =20
 
In=20 talking to Tracy, my understanding is that the alarm signal pin is on a = 5V pull=20 up, with a 10k ohm resistor.  When the EM-2 wants the light on, it = grounds=20 the pin, but when it's "off", the pin would be sitting at 5V.  If = you tie=20 the light to 12V, then there's a 7V potential across the light, with a = 10k ohm=20 resistor in series.  This will allow some current to flow, and = would=20 probably not be noticeable on an incandescent lamp, but for LED's, it = will=20 appear to be on, but dim.  
 
The fix=20 was to use one of the EM-2 5V outputs for the LED alarm = light power. =20 This gives no voltage differential when the light is supposed to be = off,=20 and 5V differential when on.  
 
If you=20 are using a pre-packaged LED that's made for 12V, and you use 5V = instead,=20 it will work but will be dimmer than it would have been with=20 12V.   You may have to use a different LED. =20
 
Tracy=20 may also have a better answer now, so stand by for the real answer=20 :-)
 
Cheers,
Rusty=20 (single rotor engine currently installed on the hanger=20 floor)
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