Dual voltages at the same time

[Bdbodger]

I want to build a mod that will have a juice pump in it . I want the mod to be VV for the atty but the pump runs at 3V DC and 0.12 W . So how can I have both VV and a set 3V DC from one set of two 18650 batteries ? I guess I will need two voltage regulars but the ones I ordered are these ones
DC-DC Converter Board regulator In:3-30V Out:1.3-18V | eBay

45mm x 38mm . There must be an easier way .


Maybe I sould just do for these instead
http://cgi.ebay.com/LM2596-DC-DC-St...910?pt=LH_DefaultDomain_0&hash=item335fab77ae

Size: 49 (L) * 23.5 (W) * 12.5 (H) mm (with potentiometer)

 

[Gummy Bear]

You can pull 3.7v off of one battery and feed the reg with the two batts at the same time, no problem.

 

[AttyPops]

A resistor and 3 volt regulator would be a simple addition to leach some power off. I assume the juice pump would be activated by a switch or some logic anyway????

 

[Bdbodger]

A resistor and 3 volt regulator would be a simple addition to leach some power off. I assume the juice pump would be activated by a switch or some logic anyway????

Well I don't know much about these things I was just going to use a horn switch or something like that . Would a regulator like this be what I need ?
http://search.digikey.com/scripts/DkSearch/dksus.dll?vendor=0&keywords=VBSD1-S3.3-S3.3-SIP

 

[bstedh]

Well I don't know much about these things I was just going to use a horn switch or something like that . Would a regulator like this be what I need ?
Digi-Key - 102-1357-ND (Manufacturer - VBSD1-S3.3-S3.3-SIP)

I would just stack two OKR regulators. 1 set for variable output and the other set to a fixed output. They will stack to together and not take up much more room than 1 would. Just place an insulator between the two boards and stager the inductor housing. I would just remove the header pins and solder wire directly to the boards.

(I think i'm starting to sound like an OKR fanatic) =] and I've only use one...

 

[retird]

Since you want to use 2 18650 batteries for the VV feature, your mod will not be small and adding juice pump takes space....tap off one battery for the pump....

 

[Gummy Bear]

I guess someone should ask if you want the pump to come on every time the atty fires? or every so often as needed?

 

[Bdbodger]

I guess someone should ask if you want the pump to come on every time the atty fires? or every so often as needed?

That is to be determined but at the moment I just want to have it only come on when the switch is pressed . It works at 0.45 ml/min and as I have never tried a pump before and I over paid for the two I bought I just want to make sure I don't destroy it . I will see how it works when I finally have it running in a mod . I am the type that jumps into the deep end of the pool before he learns to swim and that could be my down fall .The pump is 3V and one 18650 battery is 3.7 volts so I am concerned about that .

 

[Bdbodger]

Since you want to use 2 18650 batteries for the VV feature, your mod will not be small and adding juice pump takes space....tap off one battery for the pump....

Your right about the size it is not going to be portable just something for home use . I don't have many of the parts yet not even the few I have ordered but I can show you this much . The box has a skin of sorts although Digikey did not have the box in stock I have the cover and battery slot .

 

[Bdbodger]

I may have to use a different box though as the one I ordered may not be deep enough .

 

[Bdbodger]

I am sort of leaning towards the OKR-T/6-W12-C or the OKR-T/3-W12-C that bstedh describes in his other thread . Looks easy enough .
http://www.e-cigarette-forum.com/forum/modders-forum/191607-easy-okr-t-vv-mod.html

 

[bstedh]

Check the ratting on the pump. You can probably use the 3A OKR for the pump and the 6A should be more than enough for the atty. I have stressed the 6A pretty good with no issues. That will save you a couple of dollars on your build that you can spend on other exotic pieces.[ Edit: I miss read the part numbers you posted =] These are what you selected...]

If the pump will work with VV to adjust how much it pumps with each button push you can calibrate it just right so that you can run both regulators from one switch. Otherwise you may need separate switches so you only run the pump when needed so as not to flood the atty.

Make sure you take lots of pics and document issues and things you learn as you go. We are all learning from every build.

 

[Bdbodger]

Check the ratting on the pump. You can probably use the 3A OKR for the pump and the 6A should be more than enough for the atty. I have stressed the 6A pretty good with no issues. That will save you a couple of dollars on your build that you can spend on other exotic pieces.[ Edit: I miss read the part numbers you posted =] These are what you selected...]

If the pump will work with VV to adjust how much it pumps with each button push you can calibrate it just right so that you can run both regulators from one switch. Otherwise you may need separate switches so you only run the pump when needed so as not to flood the atty.

Make sure you take lots of pics and document issues and things you learn as you go. We are all learning from every build.

My thoughts exactly . The pump is low power . I tired it on an AA battery at 1.5V just to see if it would run although I didn't try to pump any juice and it ran just fine . I got another part today the regulator I had ordered . Space is a concern .

 

[Bdbodger]

Ok I ordered a couple of OKR-T/6-W12-C and OKR-T/3-W12-C two of each for this and or future mods . From your other thread Bstedh looks like I would maybe need a 500ohm resister for 3v ?

 

[bstedh]

That sounds about right. There is a formula in the data sheet for figuring out the ohms needed for a specific voltage. I haven't looked at the data sheet for the different ones to see if they use the same formula so you may want to double check that. I would use a trimmer POT however so you have the ability to adjust it to the exact voltage you desire. I never trust a $.10 mass produced part =] one of those nice multi turn blue ones would work nicely. Remember you want to be able to dial into the perfect drip amount so something like a 600 or 700 ohm trimmer might be just what you are looking for depending on how low you need the voltage to go. also you really don't need the high end limiting resistor as this won't be constantly adjusted or in the open to be accidentally changed unless you want it for a safety then you would size it for the highest possible voltage you would want going to the pump and then size the pot for how much adjustment you would like. You may need to do some experimenting with this and swap out resistors a couple of times to get it perfect. "Get a breadboard" so you can prototype everything before boxing it would be my recommendation.

Make sure to keep asking if there are any doubts about anything. Let's get this thing working nicely and make sure you snap pictures of every step you take =]

 

[Bdbodger]

They sure are small . I had ordered a few of the pcb precut boards from madvapes but I don't know if you can use them with this chip the spacing of the pins looks quite close .

 

[bstedh]

I plan on removing the header pins on my next mod and just soldiering wire into the holes. If you have a couple of good needle nose you should be able to bend them out enough to solder onto the break out board. Or just hit them with the iron to get them to turn. Not sure how much the plastic retainer with interfere with this. Just be careful not to over heat the PCB!!!

On my current mod I just tinned some wires and soldered them right to the pins.

 

[WillyB]

They sure are small . I had ordered a few of the pcb precut boards from madvapes but I don't know if you can use them with this chip the spacing of the pins looks quite close .

They are small because they are incomplete compared to your main board.

That Murata seems like expensive overkill just to to occasionally power the pump.

This would have made more sense to simply drive your pump, and no voltage adjusting resistors are needed.

2.8V 800ma

Did you check out this guy's work?

5volt-box-electric-pump

 

[Bdbodger]

Yes I seen that second link you posted WillyB . What type of board is that he used ? You can see it in the 2,3 and 4th photos .

 

[WillyB]

I'm sure it's probably a MadVapes standard fare linear Fairchild 5V reg.

More for just some layout ideas.