Micro solonids / valves

Hi,

I want to make somethink like the below. if you not seen them its streams of water that by turning on and of valves to start and stop them pattens can be made.

But i want to make a desk top one, with 3 d printing I can make a nice smooth flowing streams of water about 10mm or closer togather but my thoughts are now on how to stop and start the flow. I think the best way is to have a series of solonids that divert each of the streams.

So the water is pumped up to a reservoir from what it drains out of a row of holes. then benith the hold, below and behind the holes will be a shelf which drains back in to the base to be pumped back up.

A solonid will then push out a “paddle” that will divert the water in to the shelf or let it fall down.

can anh one point to a “cheap” ish solonid with a body <10mm diamator so I can pack them togather. When i say cheap I will need about 20+ of them so ~£5 each would work.

I found some silghtly bigger and some small one that are much more expensive.

Of the alternitive is to make some of my own but never done that before…

Any other ideas, of sugestions for a cheap way to stop start the flow. the streams are narrow and the on/off must be crisp and clean. hence why thinking solonid as it can move in and out of the water flow quickly and smoothly.

Try this link, they are less ten $2.00 Micro Electric Solenoid Valve N/C Normally Closed 12V Wires Gas Water Air Control N/O Normally Open|Pneumatic Parts| - AliExpress
I searched for: "solonid valves" Let us know how it goes.

gilshultz:
Try this link, they are less ten $2.00 Micro Electric Solenoid Valve N/C Normally Closed 12V Wires Gas Water Air Control N/O Normally Open|Pneumatic Parts| - AliExpress
I searched for: "solonid valves" Let us know how it goes.

Hi I ended up finding some small 8.8 X 10.5 mm solonids from Aliexpress :slight_smile: thansk for that sugestion, jsut had to wait for them to arrive.

Now building the valves, but to hopfully keep this smoth I am going to create a unit that has a funnel on top and a continus stream of water flowing though dropping down a narrow hole with a blade controled by the solonid able to divert the stream. the diverted stream will then drain in to the base and get pumped back to the top and flow back down. I hoping this will mean a very smooth on off.

These are the valves so far and they print out find on a 3D printer. Made them modular and there is a 6mm spacing between the holes. I wanted to make them modular and (i will build the funnel on top) so any with any issues where they dont flow correctly i can discared before building up a row of them. Then cap of the ends to have a sealed system.

For a sense of scale they valves currently are about 12mm X12mm X 24mm. so the final device will be about 30cm wide, 6cm in depth and about 20 cm high. The aim is to fit on a desk top and be battery powered (though it will have a 5v input as well)

the stream of water will be about 2mm and drop for about 10cm's. Then i am planning to make it a clock and have a strip of LED's flash in time to highlight the stream when the patten hits the mid point of the drop.

I am hoping that will help make it "pop" to the viewer. and what i would like is that unlike a lot of these displays were the image is the break in the water stream. for the clock it will be the stream of water so will apare like water hanging in the air.

My only thing now is to decided how to accuratly and quickly control about 20+ solonids from a single ardunio, I could use mutiply devices but syncing them up I am not sure about. I havent worked out the timing yet but I know they will all have to move in sync I was thinking about using SPI or i2c but thats about as far as i have get so far :slight_smile: wil cross that bridge after i have completed the mechenical part, got a single unit working with a solonid, then a block of 4 or 5 before i worry about full scale.

Once again thanks for your sugestion will report back when i have progressed further.

We need to know the voltage and current ratings of the solenoids you propose to use, before we even start to explain the necessary circuits, but it is likely to involve TPIC6B595s or similar.

For currents of up to 150 mA at about 24 V, three of these will control 24 solenoids very nicely using only three output pins of the Arduino.

TPIC6B
Has 8 available pins.
You Need to determine the power needed by one solenoid.
AND the max power you can push through the TPIC6B
That will limit how many solenoids per TPIC6B

Oh i had head the name shift register but have never played with them. But a quick look at the data sheet and i get the theory.

The solonid are rated for 3v and 3.6 ohms, as I am moving simple in and out of the water stream the lower the power the better. But this is aliexpress so I have no idea of the exact specs.

At the moment I only have a few for testing i have no experince with Solenoid i thoiught i would jsut get a few to play with. I might end up swapping them out as the current ones i have are just push but push/pull may be better. Can you simple reverse the current to "pull" the core back in? I am conserned a spring return may not be smooth / consistent and delayed making timings hard.

Once i get one up and working and have tested it a little i will look at the shift registers. Thanks for the headup on that one, that seems the way to do it.

OK now, 3.6 Ohms at 3 V is nearly 1 Amp, the TPIC series of ICs will clearly not “cut it” for this. You will need logic level FETs to drive them, not BJTs and definitely not Darlingtons (though the voltage drop in Darlingtons could arguably be employed to operate them directly from a 5 V supply :roll_eyes: ).

Nice convenient FET modules:

Aliexpress example

Note they have two FETs - because they can - but only control one device, and you will need to add the “kickback” diode across the solenoid.

The TPICs are only pull-downs so you would need to drive the FETs from 74HC595s but actually, I think a couple of PCF8575 expanders would provide sufficient outputs and be easy to drive (via I2C). While these are primarily pull-downs, they provide a pull-up pulse when switching HIGH so should drive the FETs properly.

Port expanders:

Aliexpress example

You could use a Mega 2560 instead of the port expanders but they will generally be a cheaper option used with a Nano and actually easier to program,

The valves gilshultz suggested (link corrected) are able to be directly controlled by a TPIC6B595 but I doubt would be sufficiently fast for your application and require significant water pressure.

Strange I swore i posted a responce?

What i was sayign is that I think possible I need to consider what solonids to get, They dont need to be valved as how I am constructing this is that there is a continual stream of water falling and the solonid will jsut pop out and divert it.

As below there will be a row of these with the water filling the top and flowwin down the nozzels betweeen them, when the solonid pushes out it will divert the stream into the tray below the oposite nozzle (each is off set) to the trough underneith.

I was planning on something like this, due to the size, but maybe this is not ideal.

I offer board with 32 MOSFETs rated for more than 1A that would be great for your project.


Use '595 shift register to drive the MOSFET gates, and SPI.transfer() or shiftOut() to send in 4 bytes of data.
The board has diodes across the outputs to protect the MOSFET outputs.

digitalWrite (ssPin, LOW);
for (x = 0; x :4; x=x+1){
SPI.transfer (dataArray[x]);
}
digitalWrite (ssPin, HIGH); // outputs update on this rising edge

So update the 4 bytes in dataArray as needed, and send them out when there is change.
If the solenoids need 1A to energize, then it likely has a pretty sturdy spring to retract the mechanism.

CrossRoads:
If the solenoids need 1A to energize, then it likely has a pretty sturdy spring to retract the mechanism.

It tiny with almost no restance. The other thing is that as the solenoids would need to be held for a period of time running each at one amp would be a huge energy drain and produce a lot of heat.
So i think waht i first need to do is make sure.

  1. what is the actuly current draw of the device i have both for the inital open and then to hold it open
  2. if this is to high look at what solenoid i should be using.
    It only needs to have a 3-5mm travel and around 100g pull/push (basicaly enough strenth to extend quickly with almost no load, its just extending through a stream of falling water thats ~2mm thick. )
    below is the size solenoid I am after (in fact this the test one i got), as you can see its tiny and the spring is very weak. Can i simple test with different resistance values at 5 volts to find what the lowest current the solenoid will work at.
    I also think i will need to look at something like the MPQ6610 to provide a way to reduce the holding current.

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