<controlling fire extinguisher with a servo> :frown:

[gshubham96@gm]

<controlling fire extinguisher with a servo> please help

Hi,
I am building a robot that can extinguish a fire on it's own with the help of a couple of sensors and a fire extinguisher.
I want to control the lever of the extinguisher autonomously with the help of the http://rcelectro.com/index.php?page...category_id=4&option=com_virtuemart&Itemid=4" . The robot will be equipped with a fire extinguisher. the robot is operated by 2*60 rpm (12 V) motors. so, the structure of the robot should be able to hold the weight of the extinguisher.
Which type of fire extinguisher should I use? and what should be it's weight and the most imp can this servo be used to trigger the extinguisher?
What will be the mechanism? I am thinking of a pulley type( please see the doc attached.)
I think i am wrong so please can any1 suggest me a solution for this
THankx in advance :D :D
Regards,
Shubham

 

[Skrambles]

Are you trying to control the flow coming out of the fire extinguisher? If so, you could use a solenoid valve to control it.

 

[berkeman]

Hi,
I am building a robot that can extinguish a fire on it's own with the help of a couple of sensors and a fire extinguisher.
I want to control the lever of the extinguisher autonomously with the help of the http://rcelectro.com/index.php?page...category_id=4&option=com_virtuemart&Itemid=4" . The robot will be equipped with a fire extinguisher. the robot is operated by 2*60 rpm (12 V) motors. so, the structure of the robot should be able to hold the weight of the extinguisher.
Which type of fire extinguisher should I use? and what should be it's weight and the most imp can this servo be used to trigger the extinguisher?
What will be the mechanism? I am thinking of a pulley type( please see the doc attached.)
I think i am wrong so please can any1 suggest me a solution for this
THankx in advance :D :D
Regards,
Shubham

Are you trying to control the flow coming out of the fire extinguisher? If so, you could use a solenoid valve to control it.

Speaking as a person who has a fair amount of fire extinguisher training (and having put out a few real-world fires with them), you don't modulate the handle. You squeeze it fully when you deploy the extinguisher. You can modulate it on-off-on-off every couple of seconds, depending on what the (small) fire is doing, but you don't use a half-on type squeeze for anything.

So, the best actuator would be a solenoid that you activate to fully squeeze the handle. I'd recommend using a 5-pound or 10-pound "ABC" fire extinguisher for your project, since those are the most common types that are used in buisinesses and homes.

I'm assuming that this is a school project, and not a real commercial application, right? There is a lot more that goes into fighting a fire than rolling a robot up to it and firing an extinguisher at it.

 

[gshubham96@gm]

@berkeman
You are right this is for a project.
I dind't understood how to use a solenoid. Are you suggesting that instead of a valve, extinguisher should be equipped with a electric solenoid actuator ?
well, if so
one of the major dis-advantage of a solenoid actuator is that they produce small force, so only operate in small valves

Regards
Shubham

 

[berkeman]

@berkeman
You are right this is for a project.
I dind't understood how to use a solenoid. Are you suggesting that instead of a valve, extinguisher should be equipped with a electric solenoid actuator ?
well, if so
one of the major dis-advantage of a solenoid actuator is that they produce small force, so only operate in small valves

Regards
Shubham

I guess you could retrofit an extinguisher with a controlled valve and have it recharged, but that seems like a lot of work. Plus, the extinguisher material gums up valves pretty well, so most household extinguishers are single-use only.

I was thinking that a strong enough solenoid could be used to squeeze the handle, but perhaps you're right. The handle is pretty easy to squeeze, but the throw is several cm, which is long for standard size solenoids.

 

[gshubham96@gm]

I will be using this fire extinguisher.http://www.ceasefire.in/pdf/c789bcea-dfd9-476c-bacc-fd8b00a5e059.pdf" Can it be retrofitted with a solenoid ?. will the valve able to withstand the pressure?
I can ask the company to do it.

 

[berkeman]

I will be using this fire extinguisher.http://www.ceasefire.in/pdf/c789bcea-dfd9-476c-bacc-fd8b00a5e059.pdf" Can it be retrofitted with a solenoid ?. will the valve able to withstand the pressure?
I can ask the company to do it.

What is your control algorithm going to be like? Is it going to be a single fire? Or would you want to incorporate several extinguisher shots as part of the effort? What are your overall project objectives, and how do you plan to address them at the low level (robot movement, extinguisher operation, etc.)? Honestly, with a 5 pounder, you have maybe 20 seconds, and with a 10 pounder, about 40 seconds of flow (ballpark).

If your strategic plan is to use a single fire, just use a small solenoid to pull a pin from under a big enough spring to compress the handle. If you want multiple extinguisher actuations (and if you do, why?), you will need to use a big enough solenoid with a big enough throw or leverage to depress the handle on demand, IMO.

 

[gshubham96@gm]

What is your control algorithm going to be like? Is it going to be a single fire? Or would you want to incorporate several extinguisher shots as part of the effort?

I think I will incorporate several extinguisher shots .

What are your overall project objectives, and how do you plan to address them at the low level (robot movement, extinguisher operation, etc.)?

I am making a fire fighter robot.
the extinguisher will be mounted at the top.
robot will move with the help of 2 60 RPM 12V DC motor and 5 wheels.
the extinguisher now will most probably operated by a solenoid valve.( I have a company that if they can do it.)

Well, the extinguisher is only one but the shots fired are not