Air Pump help

[FutzDesigns]

Hey all! New to the forum, long time EEVblog viewer.

I'm a total beginner, but I wanted to develop a air pump device for inflatable objects.

I gather, I need to hook a air pump up to microcontroller (I've eyed out either a PIC12LF1501-I/P-ND or a PIC12F1612-I/P-ND)

I wanted to hook up a blower that can output atlease 6 cfm (sourced out a BLOWER 50X20MM 24VDC(https://www.digikey.ca/product-detail/en/mechatronics-fan-group/B5020L24B-BSR/1570-1036-ND/5209733))

and I also looked into pressure sensors (sourced out a MPXM2010GS-ND (https://www.digikey.ca/product-detail/en/nxp-usa-inc/MPXM2010GS/MPXM2010GS-ND/420519))

My goal is to create a air pump that can pump in air when the PSI in the inflatable object falls below a certain PSI, keeping the object perfectly inflated (inflated objects loose air overtime due to temperature change, etc.) I think, without much knowledge, I can modulate the blower's output by PWM, determined by the PSI read on the pressure sensor, which variables I can set thru the microcontroller.

Does anyone have any recommendations on how I should attack this design?? looking forward to some constructive input.

Regards,

Gabriel T.

[stj]

cant you start with one of those digital blood pressure cuff's?

i have stripped one of those and they contain a nice low voltage pump, a pressure sensor, and a solenoid-valve to release the pressure.
a great collection of parts!! 

[Ammar]

Looks feasible based on what you have described. The time it would take for the pressure to drop means the control loop could be fairly crude. Perhaps just on/off controlling the pump based on a threshold pressure. Fairly unlikely to oscillate. A PID controller with PWM on the output could be overkill, but it depends entirely on your needs.

[stj]

btw, you need a pump - a fan has no real pressure behind it.

[FutzDesigns]

Thanks for the replies, does anyone know any good distributors for air pumps? Can't seem to pin-point anything with a quick google search, all I get are off the shelf consumer pumps, no parts manufactures...

Well def look into *aussie voice* tearing apaaart a digital blood pressure cuff, seems like it'd have the same concept.

Is there a way I can achieve this without programming a microcontroller?

Regards,

Gabriel T.

[stj]

you can do anything without a microcontroller.
the question is, would you want to?
they can save you a huge amount of parts.

[lwatts666]

Is there a way I can achieve this without programming a microcontroller?

The simplest method is just an (adjustable if necessary) mechanical pressure switch and the pump.

[AG6QR]

btw, you need a pump - a fan has no real pressure behind it.

Probably.  But maybe not.  We haven't heard anything about the inflatable object yet.  How much pressure?  How much volume?  What leakage rate?

Though if a fan will be appropriate for the job, there's probably not much of a control loop needed -- you can just select an appropriate fan and power it continuously.  If you ever turn a fan off, it will let air rapidly escape unless you seal off the inlet somehow.  Fans work for things like those jumpy bouncy houses for kids, for some kinds of holiday lawn ornaments, even for the roofs of some stadiums.  They work for low pressure, high volume situations, and will handle reasonably high leakage rates.


If the inflatable thing is a higher pressure device, there are off-the-shelf air pumps with a pressure switch cutoff.  Most mains-powered air compressors for powering pneumatic tools and for inflating vehicle tires have this type of mechanism to pump the tank up to a standard pressure, and many have an adjustable pressure regulator on their output.

[JacquesBBB]

If you are a beginer, your best solution will be probably with an arduino and a pressure sensor like this one

http://www.ebay.com/itm/Pressure-transducer-or-sender-stainless-steel-for-oil-fuel-air-water-Multichoice-/331948290965?var=&hash=item4d49a8f395:m:mJ-YYz9oj5Ckz3BMsAVA8MA

You can then drive a relay that will turn on the pump at the desired level.

You can take this arduino nano for 2.5$ that you can program right away on your computer usb port.

http://www.ebay.com/itm/MINI-MICRO-USB-Nano-V3-0-ATmega328P-CH340G-5V-16M-Micro-controller-board-Arduino-/291906862007?var=&hash=item43f7013bb7:m:m1oFxGKRN6SvFgacfIECatg