Hi guys,
Thanks in advance with help from a novice.
I am trying to devise a pumping system that involves 3 input reservoirs filled with water and 1 output. The system needs to operate as follows:
- Pump the contents of input n into the output reservoir.
- Wait x minutes
- Pump contents out of output reservoir back into input n
- repeat for input n+1
For those who are curious, this is for the purpose of automating the development of photographic film.
Having read up on the problem space as much as possible I have understood as much:
- I am going to need 2 pumps as the flow of cheap 12v pumps is not reversible
- I am going to need 3 solenoid valves for each input to control which one gets activated
I have drawn up by hand a small diagram representing the layout for the hydraulics (apologize for the terrible draftsmanship). I hope my intuitions are correct.
My question is: Can I control these many motors with an arduino uno and how?
I was previously advised to use an L289n driver but this can only drive 2 dc motors. Could the uno fit 3 l289n drivers? Is there a chip that could support 5 separate motors?
Any and all advice is welcome as well as any schematics you know of that could help guide me in this journey.
Cheers.
What volume needs to be pumped each time? How quicly does that volume have to move? How accurate each volume?
My question is: Can I control these many motors with an arduino uno and how?
Sure, With the proper peripherals you can control hundreds of motors.
I was previously advised to use an L289n driver
Please top taking advice from that source. There are many modern motor drivers that are so much better and still low cost. Anyway, you choose the driver after the motor, never the driver first. Figure out what pump will work then choose the driver.
People still develop photographic film?
The problem I see with your scheme is quickly cross contaminating the chemicals. Is this a problem?
Paul
Paul_KD7HB:
People still develop photographic film?
Paul
Hi Paul, yes there are still a few enthusiasts out there 
Paul_KD7HB:
The problem I see with your scheme is quickly cross contaminating the chemicals. Is this a problem?
Paul
Cross contamination isn't a problem as the second bath in the process (input 2) is an acid designed to neutralize the first bath before the third bath is pumped. So that's already covered chemically.
(for the curious, the solutions are an alkali developer, acidic stop bath, acidic fixer).
groundFungus:
What volume needs to be pumped each time? How quicly does that volume have to move? How accurate each volume?
The volume is 500ml. It needs to be done to completion in under 15 seconds. The amounts are pre-measured and accuracy is not very important.
For referene here is the pump that I was hoping to source:
and the solenoids:
groundFungus:
Please top taking advice from that source. There are many modern motor drivers that are so much better and still low cost. Anyway, you choose the driver after the motor, never the driver first. Figure out what pump will work then choose the driver.
Fair do's. Any recommendations?
Cheers.
Fair do's. Any recommendations?
The pump will turn in only one direction and the fill and pump back by solenoid valving, right? If so the pump can be controlled by a logic level MOSFET (with a couple resistors and a diode). The solenoid valves will need similar drivers. The solenoid link is the same as the pump.
I would use multiple pumps instead of solenoids to choose what gets pumped, where. Makes the plumbing easier, for starters. It also reduces parts count from four (three solenoids + one pump) to three (thee pumps).
wvmarle:
I would use multiple pumps instead of solenoids to choose what gets pumped, where. Makes the plumbing easier, for starters. It also reduces parts count from four (three solenoids + one pump) to three (thee pumps).
Unless I am mistaken that would require 6 pumps as its 1 pump to pump in and another to pump out.
Unless there are any 12v pumps that pump in two directions.
Haven't been able to find anything like that but then again my knowledge is limited.
Yes, 6 pumps total. I was thinking of just one direction.
But no solenoids. Otherwise it'd be two pumps and six solenoids.
The hard part you will have is to get everything back out. All pumps have to be connected to the lowest point of the container, in a way that prevents much cross contamination... could be tricky to do.
As far as piping layout.. have you considered a reversing valve. You could then effectively make your pump bidirectional. The pumps inlet source could be decided by the reversing valve weather it pulls from 3 holding tanks and pumps to working tank or vice versa
