Air pressure operated switch

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Bbennyx
Posts: 4
Joined: Wed Jun 28, 2017 11:23 pm

Air pressure operated switch

Post by Bbennyx » Wed Jun 28, 2017 11:43 pm

Hi. I'm a newbie here and to electronics in general having taken up the hobby on retirement to keep the grey matter churning. Consequently I'm a bit unsure as to the best components to use for a project. At the moment I'm trying to build an automatic switch for an e cigarette, that is one that will work simply by drawing air through it with no manual operation. It needs to be small for obvious reasons, and be capable of passing a current of 3.7v. I've spent hours on the interweb trying to track one down, but have a feeling I'm searching for the wrong thing! If this is a stupid question or one with an obvious answer I beg your indulgence, but would really appreciate any help you could give in sourcing something suitable. Thank you for your time.

David
Posts: 216
Joined: Sun Oct 04, 2015 6:18 pm

Re: Air pressure operated switch

Post by David » Fri Jun 30, 2017 8:59 am

Hmmm... Not an obviously easy project. Where are you expecting the switch to be? Is it to be on the mouth end or the far end of the e-cig? Could it be mounted in a box which sits on a (say) nearby table?

I have in mind that the differential pressure between the two sides of the switch in the airflow will be small. Therefore the mode of action will probably be something like a vane in the airflow, the movement of which will be sensed by some form of opto switch. The vane part would have to be mounted in a stable place (obviously) - probably connected to the e-cig by a plastic tube.

RS has some pressure switches, which may be suitable, but they seem to be quite expensive (>£100) and we do not know what pressure range in the e-cig to expect.

What ideas have you had? can you expand any further?

Bbennyx
Posts: 4
Joined: Wed Jun 28, 2017 11:23 pm

Re: Air pressure operated switch

Post by Bbennyx » Sun Jul 02, 2017 5:41 pm

Hi David, thanks for taking the trouble to reply. The switches I'm thinking of already exist, mostly in low end throwaway e cigarettes, or mounted in the batteries themselves though these have become vanishingly rare. My idea is to mount the switch in the stem of a pipe, with the battery in the bowl and the workings in the mouthpiece so that it operates exactly the same as an 'analogue' pipe.I've had some success with parts salvaged from other bits and pieces so I know it's not impossible, but felt it would be more elegant... and fun... to try to make my own. My stumbling block at the outset is, as I mentioned in my post, that I'm new to the hobby and don't know what these bits are called in order to order them! The most simple form I can imagine would be a diaphragm which, when sucked, closes a switch allowing current to flow. Any further ideas would be most welcome. :D

David
Posts: 216
Joined: Sun Oct 04, 2015 6:18 pm

Re: Air pressure operated switch

Post by David » Mon Jul 03, 2017 11:45 am

Hello.

I wasn't aware that the switches exist (I'm not a smoker), but given that they exist, why not cannibalise one of the throwaway e-cigs and use the switch from that? If you could post a photo of the various parts that may give a clue as to their descriptions.

Bbennyx
Posts: 4
Joined: Wed Jun 28, 2017 11:23 pm

Re: Air pressure operated switch

Post by Bbennyx » Tue Jul 04, 2017 7:29 pm

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I found these online provided by our Chinese bretheren... the only trouble is that the minimum order is for 100 units! :o
Attachments
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HTB1Z2nWHXXXXXXmapXXq6xXFXXXL.jpg (108.4 KiB) Viewed 5082 times

David
Posts: 216
Joined: Sun Oct 04, 2015 6:18 pm

Re: Air pressure operated switch

Post by David » Fri Jul 07, 2017 10:31 am

Many thanks for the pics. They certainly give me an idea of what goes on in an e-cig. In your first post, you said that you want to build an "e-pipe", along the same lines as an e-cig. Why not therefore dismantle an e-cig, and rebuild it inside a pipe?
I have in mind that the components in any e-cig would be already a) as small as possible, and b) optimised for vaping. The switch to which you referred in your original post would seem to be in the microprocessor or just to its right in the picture.
I'm sorry, but I have no idea where you could get these components in small quantities - hence my suggestion of rebuilding an e-cig in the guise of a pipe! I wish I could be of more help.

Bbennyx
Posts: 4
Joined: Wed Jun 28, 2017 11:23 pm

Re: Air pressure operated switch

Post by Bbennyx » Mon Jul 10, 2017 6:40 pm

Your ideas are sound David, and I'm already a fair way along the route you suggest. Seems like great minds DO think alike, after all! ;) I've sourced the all the other parts required to make a very usable pipe - as you suggested, from old e cigarette parts - but would really like to develop an understanding of the clever bits so as to be self reliant in this area. I've found that fashion, and hence commercial availability, is moving away from automated e cigarettes toward manually operated switches making it progressively more difficult to find the items I need, so I figured the way forward may be to make my own, hence the post. I'll probably reveal my stumbling newness to the hobby by saying that I found your comment regarding the switch being in the microprocessor very interesting and imagine that this is possibly the part I need to be finding, rather than anything including the word 'switch' which, I can assure you, is a dead end on google as far as my requirements go. I'd like to thank you again for taking the trouble to reply, and if this new lead in my endeavors bares any fruit, I'll let you know. Thanks, David.

David
Posts: 216
Joined: Sun Oct 04, 2015 6:18 pm

Re: Air pressure operated switch

Post by David » Tue Jul 11, 2017 11:24 am

You are very welcome.

NoellEagan
Posts: 1
Joined: Tue Oct 17, 2017 3:20 pm

Re: Air pressure operated switch

Post by NoellEagan » Tue Oct 17, 2017 3:34 pm

Hi..i am a new user here. As per my understanding the differential pressure between the two sides of the switch in the airflow will be small. Therefore the mode of action will probably be something like a vane in the airflow, the movement of which will be sensed by some form of opto switch. The vane part would have to be mounted in a stable place,probably connected to the e-cig by a plastic tube.

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