From: Manu Abraham <abraham.manu@gmail.com>
To: Microcontroller discussion list - Public. <piclist@mit.edu>
Sender: "piclist-bounces@mit.edu" <piclist-bounces@mit.edu>
Date: Thu, 26 Nov 2020 10:18:00 -0800
Subject: Re: [EE] Current Sense Project
Thread-Topic: [EE] Current Sense Project
Thread-Index: AdbEIbBaXbkXPwecSnGPTSUw/7Z1Sg==
Message-ID:
 <CAHFNz9JGm0CwMYkNtzn5oo-jXHpWcCnji+a==upbMXWf_MgMAw@mail.gmail.com>
References:
 <CAD2N_E8SKNGVyfvMSqwEP9zAVgXW80mJvxAD5LY_e6Kg-8LyhA@mail.gmail.com>
In-Reply-To:
 <CAD2N_E8SKNGVyfvMSqwEP9zAVgXW80mJvxAD5LY_e6Kg-8LyhA@mail.gmail.com>
Reply-To: Microcontroller discussion list - Public. <piclist@mit.edu>
Accept-Language: en-US
X-MS-Exchange-Organization-SenderIdResult: Pass
X-MS-Exchange-Organization-PRD: mit.edu
X-MS-TNEF-Correlator:
received-spf: Pass (protection.outlook.com: domain of gmail.com designates
	209.85.219.179 as permitted sender) receiver=protection.outlook.com;
	client-ip=209.85.219.179; helo=mail-yb1-f179.google.com;
dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com;
 s=20161025;
	h=mime-version:references:in-reply-to:from:date:message-id:subject:to;
 	bh=YQbppLzSIZheVTRSuaAy5YLCFyOx8g2AWZaL14THBPI=;
	b=GBbcpCA7R/NIR1nK8b+adoibH8PY3B9pv1kFM7pFO+6bEW3FaEU9xCQmGBfZceDyRL
	RS/ArxEhh+r4fELqJBpWVfuGR61Sj37DQsU0A8suvqUg8MOGfhSi0gg+kUkxZTEIwRJc
	W1e9Hq9vFTACEuoUU3EyrZeLLuNrjs+4SPnsRnC0A663gSU0vWNEavpUwEf5U3sBNj+F
	un9I4fKw0BSslAAC6E4G7vwA0V+3a6RovfpJE+dOatV90ph4yM5f6PHEnfIDB5MFNJ+i
	NX43R1+6DF5O4ddVYl5q7u7uR8zAsLn6PT8V4W99VBcnmlBxB9yLHljeNNuwMK7RXwPg	FXoQ==
authentication-results: spf=pass (sender IP is 209.85.219.179)
	smtp.mailfrom=gmail.com; mit.edu; dkim=pass (signature was verified)
	header.d=gmail.com; mit.edu;	dmarc=pass action=none header.from=gmail.com; 
errors-to: piclist-bounces@mit.edu
list-id: "Microcontroller discussion list - Public." <piclist.mit.edu>
list-post: <mailto:piclist@mit.edu>
x-beenthere: piclist@mit.edu
x-mailman-version: 2.1.6
x-received: by 2002:a25:680d:: with SMTP id
 d13mr6062199ybc.92.1606414690734; 	Thu, 26 Nov 2020 10:18:10 -0800 (PST)
x-topics: [EE]
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0

On Thu, Nov 26, 2020 at 11:04 PM Josh Koffman <joshybear@gmail.com> wrote:
>
> Hi all,
>
> I'm thinking about throwing together a quick monitor for my block
> heater. I'd like to know when I forget to plug the car in (because
> let's be honest, it's going to happen...). I've got a small current
> transformer on the way (5A/5mA). I'd like to trigger a relay that
> lights up a 120V indicator light when the block heater is plugged in
> and powered.
>
> My "current" thought is to run the transformer to an ADC on a micro
> and use it to trigger a relay. Am I missing an easier solution? Could
> I run the output of the current transformer to an opto that triggers
> the relay? I would lose the "tweakability" of levels though.

Option #1
Use a transistor and a pot to set the trip point.

Option #2.
Use a zener to set trip point, maybe a TL431 even

Option #3
Use an opamp as a comparator, or maybe even a 555 timer

Option #4
use a microcontroller with a builtin ADC

Option #5
use a microcontroller with a builtin comparator

Could be a lot more options, though.


Cheers
Manu
--=20
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.