(03-12-2012 8:11 PM)Fly So Hi Wrote: I'm pretty sure they have to be used with tips. But something like US$ 45,00 for 1000 tips.
Okay, so you're serious about making a "Pheromixer 2000".
I think one of the things you might need is a linear actuator to act on the plunger, that would probably be a syringe or a fixed volume pipette. Actually, there are pipettes/pipettors that are made using exactly this model of actuator. Of course you'd need to figure it out how much turns your actuator would have to turn to draw exactly the desired volume.
Second, you'd need yes, the motor, to move the "needle" on the horizontal axis (just like an inkjet printer) to draw the liquid out of the bottles. Remember you'd have to move the whole mechanism (actuator thing) left and right to make this work (again, just like a printer).
Something like this.
To make it easier, I suggest you use a step motor to rotate some sort of plate/dish where your concentrate bottles will stand. Just like a roulette, got it? The tricky part of this is that you have to make sure the needle/tip always stays below the liquid surface. Maybe you'd need another linear actuator to either push this plate up or the needle down.
The machine would also have to know which slot in the rotating plate contains which molecule. Once you're planning on using a microcontroller, it would probably be best if you throw a few more code lines so you could say to the machine which slot contains which molecule.
The resistor/transistor part of the circuit itself is really ease to make.
It would take a bit of work, but seems you're comfortable with mechatronics and programing, so it will be easy for you.
Great minds think alike I suppose.
This is pretty much exactly what I was thinking and planning. I started by building my own linear actuator which I talked about in the first post, figuring that while the tracking from bottle to bottle and programming would be no less difficult, it would be far less important as far as how well it does the job. The linear actuator on the other hand is one of the most important parts, the other stuff is pretty much just to move it around. However after I had gotten a fairly satisfying result using 2 chained worm gears (probably the best thing to use in this situation) and slight springs to apply pressure to them to better mesh the gears, I realized I might have been more accurate than the syringes I was going to be using anyways.
I was thinking rotary as well for holding the bottles at first, but I'd also like to fit this into a relatively small place if possible. This will be a "Pheromixer 2000, Home Edition" so to speak if I can manage it. I set a goal for myself to try to make it fit in a shoebox. Might be useful as well to have it fit onto the fridge shelf.
I was thinking a grid would be most space efficient. So I was thinking a track built above this grid of bottles with a track curving from one row to turn the thing around to go down the next row, thus using a single motor to go back and forth down the rows.
I was also planning on having a covering which went over the grid of bottles with a soft sealing material to seal them when it is lowered. I think the motor that drives it around the track could initially slide this covering off like a drawer and then slide it back on when it gets to the end of the track. This way, the need for having the machine deal with the caps is removed, but if I forget or don't have time, they still will be sealed at the end. Also it should work pretty well even with different bottle sizes if I add set screws to the bottom of the platform to raise or lower the heights of the bottles properly.
As far as lowering the syringe/pipettes, I agree there needs to be something to do that, and while technically it should be possible to gear things from the same motor that drives it around the track, the gearing on that track motor would start to be a nightmare, and I think if you had independant control over that it would be better, because of what you just said. The microcontroller would also need to keep track of the height of the liquid in each bottle, which it would have to calculate based on being given the radius or other dimmensions. I might have an option for adding another shape to the bottle at the bottom (besides the cylinder part) such as a cone, because bottles with tapered bottoms would work much better. But if I have it keep the tip well enough below the surface, it shouldn't be an issue for most bottles.
I was thinking that the same motor moving the pipette/syringe as a whole up and down could also rotate the mix bottle underneath when the pipette/syringe is raised to its highest point.
So in conclusion it would happen something like this:
You put the bottles in, tell it how much fluid is in each, and an approximate of their dimensions. Give it a mix's instructions and off it goes.
The track motor starts up, and the lid/cover is slid off exactly one bottle ahead (behind in the other direction) of the linear actuator.
The linear actuator is pushed towards the pipette tip/syringe by the main track's motor, and after making good contact with the parts holding those up, is able to control them. The linear actuator then takes up any slack by moving a little in the upward direction.
The motor for moving the syringe/pipette as a whole lowers the tip into the liquid, and rotates the mix bottle down and out of the way.
The linear actuator pulls the liquid into the syringe while the motor lowering/raising the whole thing keeps the tip in the liquid.
The motor raising/lowering the linear actuator raises the pipette/syringe and rotates the mix bottle up beneath the pipette/syringe.
The linear actuator puts the pipette/syringe all the way back to the "0" calibration, expelling all the fluid it can into the mix bottle.
The track motor moves the whle thing down another bottle.
Rinse and Repeat.
Shouldn't be too hard, which is why I'm going to try to fit it into a shoebox and see if it is possible to make one for as cheap as possible. The first time around though I don't think I'll worry about how cheap it is too much just to avoid the hassle, but eventually I'd like to get to something simple enough and cheap enough for lots of people to build.
Without getting too far ahead of myself (haha little too late)
It will be more important to find out how these sprayers perform I think, and will also give the community immediate info they can work with, rather than some yet-to-be-optimized design that will likely have some kinks in it to work out at first. And like I said, the sprayer will probably be the weakest link in the chain of events delivering the molecules to the skin, so it would be the best use of time to look into tightening up that first.