so im working on a simple project. i have 2 2hp(1.75 actually) motors, and 2 water tanks 6 stories above.
A arduino/avr micro controller has to read data from 2*2 water sensor and turn on/off 2 30amp relays[Yes, i have considered the inrush current of the motors]//\
1.Is a arduino nano/ attinyxx reliable enough for this project? i mean this is for my elderly grandparents, so if the mcu fails or has any error somehow, the water bills gonna go through the roof.
2.a project such as this requires a fixed amount of pins, so am i better of with arduino or attiny while also keeping the above question in mind?
The distance of the sensor from the controller is an average 90~100 feet (28~30 meters). what type of sensor am i better of with. i think something like 1 wire is even out of the question. would analog sensors do? like thishttps://www.techshopbd.com/product-categories/water/3455/water-sensor-china-techshop-bangladesh
4.Can the signal survive the 30 meter distance? The wire im going to use is standard electrical wire (1.5 mm house wire) If not, whats my option?
kaseftamjid:
1.Is a arduino nano/ attinyxx reliable enough for this project? i mean this is for my elderly grandparents, so if the mcu fails or has any error somehow, the water bills gonna go through the roof.
The controllers are perfectly reliable.
2.a project such as this requires a fixed amount of pins, so am i better of with arduino or attiny while also keeping the above question in mind?
The advantage of a Nano is that it has everything you need to actually use the thing on board already. For a one off there's generally no cost advantage to use a 'tiny. Even when making your own PCB it's a perfectly good idea to solder a complete Nano onto it.
The distance of the sensor from the controller is an average 90~100 feet (28~30 meters). what type of sensor am i better of with. i think something like 1 wire is even out of the question. would analog sensors do? like thishttps://www.techshopbd.com/product-categories/water/3455/water-sensor-china-techshop-bangladesh
Get a proper sensor. Just about any float switch would do the job MUCH better and MUCH more reliable than that cheap POS (and no, it's not usable as water level sensor).
4.Can the signal survive the 30 meter distance? The wire im going to use is standard electrical wire (1.5 mm house wire) If not, whats my option?
Usually - yes. Depends on your electrical environment. A float switch is a simple on/off connection, making noise really easy to filter out.
i cant find a good quality water level switch in here. is there any alternatives, incase i dont find one
it also didnt occur to me before, i actually need to know if the tank is getting empty or not, the float switch can do the high side, what about the low side?
I use two of these, float switches along with an Arduino nano to monitor and control the water level in my irrigation storage tanks. Utterly reliable.
The switches are mounted in PVC pipe, one near the bottom and one near the top. All sealed into the pipe and the pipe top and the wires are mounted through a hole in the top of a tank.
Easy to implement; hard to make last (they're not water proof so without protection likely to stop working within half a year to a year). That sensor does have waterproof versions as well.
Paul_KD7HB:
I use two of these, float switches along with an Arduino nano to monitor and control the water level in my irrigation storage tanks. Utterly reliable.
The switches are mounted in PVC pipe, one near the bottom and one near the top. All sealed into the pipe and the pipe top and the wires are mounted through a hole in the top of a tank.
Paul
im surprised by how similar our models are.. Yes, thank you so much
counting the wires, Every switch needs 2 wires, so 430 meter wire per tank so i have to buy 24*30=240 meters of wire to buy!! The wire cost is going to be through the roof,many times the price of the actual control circuitry.
Can i use magnet wire for the switches? how much electrical interference do i have to worry about, my wires are going to run down guided by a water pipe,similar to paul's
You need thin signal wire - that's cheap, I recall paying around 10 USD for a roll of 100m 3-core wire (the ground wire can be shared between switches - it's ground + 1 per switch what you need - if the two tanks are close together you may use a single cable with five conductors, plus of course a few short bits to get to the individual switches).
Then start to actually search. No way you can't find standard 0.12-0.2mm2 wire. Can't imagine any country in this world is that backwards. Otherwise, there's always Ebay.
You want shielded wire for 30m outside if there's any chance of lightning striking anywhere in about that distance. Plain wire has another name; it's "antenna".
I'm puzzled about why a controller is needed to keep a water tank filled. If there is some kind of log or report or control that limits use when the tank is low then I could see that but 2 level sensors and wired logic to a relay will do the basic job.
The code you put on the Arduino, make sure that that is dependable too.
GoForSmoke:
You want shielded wire for 30m outside if there's any chance of lightning striking anywhere in about that distance. Plain wire has another name; it's "antenna".
I'm puzzled about why a controller is needed to keep a water tank filled. If there is some kind of log or report or control that limits use when the tank is low then I could see that but 2 level sensors and wired logic to a relay will do the basic job.
The code you put on the Arduino, make sure that that is dependable too.
One problem I discovered that a microcontroller can handle, where the wire logic would have a problem is: The tank is filled from the top with and air gap. Very near the level to shut off, the waves on the surface would turn the full float switch off and on and cause the fill solenoid valve to cycle on and off. The code shuts down permanently for this cycle the first time the float switch indicates full.
A flip flop IC can solve that problem just fine. You'd want something like that anyway or the inlet would switch on any time the water drops enough for the top valve to open, instead of waiting to reach the lower level.
wvmarle:
A flip flop IC can solve that problem just fine. You'd want something like that anyway or the inlet would switch on any time the water drops enough for the top valve to open, instead of waiting to reach the lower level.
would you please explain? the reason i went on and plan this with an arduino because i have more knowledge on that comparing to logic circuits.
tbh, a logic ic would even be cheaper, but arent they more prone to that antenna wire problem?
The third NAND U1C (the 74HC00 is a quad NAND) is to invert the signal of one of the switches; I assume the switch closes when water is above the switch level.
I omitted the fourth NAND, you have to connect its inputs to GND, and leave the output unconnected.
Of course you still have the antenna problem. You somehow have to bridge that distance after all, but usually that won't be too big of an issue.
Paul_KD7HB:
One problem I discovered that a microcontroller can handle, where the wire logic would have a problem is: The tank is filled from the top with and air gap. Very near the level to shut off, the waves on the surface would turn the full float switch off and on and cause the fill solenoid valve to cycle on and off. The code shuts down permanently for this cycle the first time the float switch indicates full.
Paul
Would indicate faulty positioning of the upper level sensor. Don't engineer problems into a design, engineer them out.
wvmarle:
Of course you still have the antenna problem.
This seems like quite a promising solution, but i dont have any idea about what errors to expect from the antenna wires. We do sometimes have thunderstorms, but i dont know how much of that will a magnet wire pick up.( I think i have to ultimately work with magnet wires as they are readily available near me and really cheap too!)
I really do have to know about possible problems i might run into. As i mentioned before, this project is for my grandparent's. Just the most subtle hint of error,BOOM, they dont trust this anymore..
wvmarle:
You'd want something like that anyway or the inlet would switch on any time the water drops enough for the top valve to open, instead of waiting to reach the lower level.
If i only use a Top valve, wont that turn the motor on/off very frequently? moreover, the water is for household usage, and knowing the fact that the mains water has some impurities during this time makes me worry about settled sediment. as the water level can never cross the limit of the top level switch, a certain amount of water is always still in the tank.
kaseftamjid:
If i only use a Top valve, wont that turn the motor on/off very frequently?
Indeed - that's why there's the second switch, at a lower level. Say 70% of the tank. When the water level drops that low, it fills up completely. It's giving you what we call hysteresis.
moreover, the water is for household usage, and knowing the fact that the mains water has some impurities during this time makes me worry about settled sediment. as the water level can never cross the limit of the top level switch, a certain amount of water is always still in the tank.
That would mean regular cleaning of the tank - periods of weeks, months, years: depending on how bad the problem is.
I don't see it as an issue for this system, though. You never empty the tank completely (unless main water supply is down), and you definitely should make sure the water outlet is sufficiently above the bottom, so sediment stays in the tank and only clean water comes out.
