Arduino based clamp system

Hi,

My name is Mar and I am a Biomedical Engineering student.

I'm enrolled in a project which consists of a sensor that detects presence of liquid in a tube. When the sensor output is 1 (i.e., there's liquid) I want to send a signal to a clamp (designed or bought) to press the tube in order to stop liquid from passing through.

Does anyone has any suggestions or ideas on how to address this aim?

Thanks in advance!!

Mar.

marmm:
detects presence of liquid in a tube

Have you already sourced the hardware and are looking to put it together and code it up or are you starting from zero?

If from zero, optical detection might work if it is a transparent tube and a nontransparent liquid.
If you have things and are just putting them together, what have you tried?

marmm:
I want to send a signal to a clamp (designed or bought) to press the tube in order to stop liquid from passing through.

If this is a soft flexible tube you should able to squeeze it shut with a servo. Servos come in a wide range of sizes and are very easy to control with the Arduino Servo library.

If you need more help a diagram of your proposed apparatus would be a good idea. See this Simple Image Guide

...R

Hi bigred1212! It is from zero but I already have the sensor system planned, I’m stuck in the second phase wich consist of this clamp system. I really don’t know how I can use the output of the sensor as the input to move the clamps.

bigred1212:
Have you already sourced the hardware and are looking to put it together and code it up or are you starting from zero?

If from zero, optical detection might work if it is a transparent tube and a nontransparent liquid.
If you have things and are just putting them together, what have you tried?

Hi Robin2! Thanks for the information. I am not able to attach an image since I could not fins anything similar on any website. Do you think it is possible to squeeze a tube with a servo motor? I would like to squeeze up to the complete stop of the flow inside a tube of 1cm diameter and an inter diameter of 0.8 cm of a soft material.

Robin2:
If this is a soft flexible tube you should able to squeeze it shut with a servo. Servos come in a wide range of sizes and are very easy to control with the Arduino Servo library.

If you need more help a diagram of your proposed apparatus would be a good idea. See this Simple Image Guide

...R

marmm:
Hi Robin2! Thanks for the information. I am not able to attach an image since I could not fins anything similar on any website. Do you think it is possible to squeeze a tube with a servo motor?How?
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Describe the tube. How big is it? Is it like IV tubing? How much pressure is the liquid under?
For a clamp, consider designing a tubing clamp with a DC motor driving a screw to tighten the clamp.

Be sure to design for "fail safe" in case the power is interrupted or hobby devices happen to fail. IF the clamp is closed to stop fluid flow and the power is removed, should the clamp remain closed. Or if the fluid is discovered, but the clamp fails to close, what are the results?

Clamping with a servo is easy if you have a cam turned by the servo so as to press the tube against a solid base. Or there may be other ways.

Can also use the servo to operate a toggle clamp to do the same thing. Or a solenoid to either hold the tube open until the solenoid is released to close the tube.

Many options, but all rely on your decision about failure method.

Paul

marmm:
I'm enrolled in a project which consists of a sensor that detects presence of liquid in a tube.

You have this sensor in place and working already?

The clamp system you could use indeed depends on the parameters of the tube, the required reaction speed, failure modes, etc.

A servo won't hold position when powered down. I would probably be looking for a screw based clamp, as it does not need any power to hold position, but it depends on the rest of your requirements.

wvmarle:
A servo won’t hold position when powered down.

That would only be relevant in certain circumstances that are easily avoided.

First, most servos have a large frictional load due to their gears and with suitable choice of a servo relative to the load I would expect the friction to easily hold position when unpowered.

Second, if the “hold” position is designed so it presents no torque on the servo arm it could stay in that position forever.

…R

Robin2:
That would only be relevant in certain circumstances that are easily avoided.

First, most servos have a large frictional load due to their gears and with suitable choice of a servo relative to the load I would expect the friction to easily hold position when unpowered.

Second, if the “hold” position is designed so it presents no torque on the servo arm it could stay in that position forever.

…R

If the default position, I.E., no power, were to be closed and power is required to open the servo/clamp, then you would have your fail-safe.

If the default position, I.E., no power, were to be closed and power is required to open the servo/clamp, then you would have your fail-safe.

Suppose that the power failed when the servo was not in its default (closed) position ? How would it fail safe ?