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Help me build a weight sensor circuit

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scdoro

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Weight Sensor

Hi All,
I need to build a device that are build on the drip and can detect and alert me when the weight of water drops from ( let say 500ml to 10ml ) . Meaning when the water in a full fill drip bag drops to a level of 10 ml, i will be able to detect that.( there is no need to give me the exact reading when the weight is dropping.).all i need is to alert me when the water goes below the weight of 10 ml. I was thinking of getting that to trigger an alarm. i have no idea where i should start from.. and was wondering how to build that weight detector circuit using ??
oh, btw, the specification of my sensor is between the range from 1000ml to 10 ml
that will be great.
Thanks for ur help..thanks
 

Noman Yousaf

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Weight Sensor

oh brother
this is very easy to build, just use a spring, has the tension according to the weight of drip, then use a micro switch. it will be connected on the top of spring fitting. when drip will loose the weight bottom of spring will go up and at last it will press the switch then you can sense it.

bye
 

Tohu

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Re: Weight Sensor

Hello,
I think that IanP idea is most suitable. If the water surface is too large, this 10 ml will be very small change of the level, and respectively to the pressure.
Using mechanical system is possible, but i think that not be very accurately or will be very complexity if you want to have good resolution with big volume of the water, for example if you have only 1 l water ,10 ml will be a possible to get with spring and micro switch, but if you have 10 l i think that will be very difficultly to give this resolution.

About tenso sensor, this that suggest IanP, you must now that this is resestiv bridge, and if you want good accuracy must use differential amplifier with a small offset and good S/N ratio.
 

yigiter

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Re: Weight Sensor

I am agree with IanP and Tohu.
A miniature load cell would be the most suitable solution.
 

du1noz

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Re: Weight Sensor

Is there a sensor which can measure weight to as low as 1 gram ?
 

polymath

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Re: Weight Sensor

Hi scdoro
Have you considered using a Hall Sensor?
Magnet+spring+Hall Sensor

Linear Chopper Stabilised Hall sensor = very stable conditioned output (eg. 0-5v).

If you want a simply binary output - good/bad level then use a Hall Switch.

Both types can be placed in a current loop for simple remote noise tolerant connection.

You could use battery+rfPIC+Hall Sensor for wireless monitoring

Just a few more options ... Polymath
 

yousafzai

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Re: Weight Sensor

U can use ultrasonic sensing for checking the level of water. Off the shelf ultrasonic sensors are available and u can interface them to any microcontroller and will be alerted automatically.
 

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