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Topic: How reliable is the arduino (nano preferably, attiny xx is also considerable) (Read 358 times) previous topic - next topic

kaseftamjid

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?

3. 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?

wvmarle

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.


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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.

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3. 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).

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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.
Quality of answers is related to the quality of questions. Good questions will get good answers. Useless answers are a sign of a poor question.

kaseftamjid

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?


https://www.techshopbd.com/product-categories/miscellaneous-98724/1343/sonar-sensor-hc-sr04-techshop-bangladesh

would this be hard to implement?

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

wvmarle

https://www.techshopbd.com/product-categories/miscellaneous-98724/1343/sonar-sensor-hc-sr04-techshop-bangladesh

would this be hard to implement?
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.
Quality of answers is related to the quality of questions. Good questions will get good answers. Useless answers are a sign of a poor question.

kaseftamjid

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 4*30 meter wire per tank so i have to buy 2*4*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

wvmarle

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).
Quality of answers is related to the quality of questions. Good questions will get good answers. Useless answers are a sign of a poor question.

kaseftamjid


wvmarle

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.
Quality of answers is related to the quality of questions. Good questions will get good answers. Useless answers are a sign of a poor question.

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.
1) http://gammon.com.au/blink  <-- tasking Arduino 1-2-3
2) http://gammon.com.au/serial <-- techniques howto
3) http://gammon.com.au/interrupts
Your sketch can sense ongoing process events in time.
Your sketch can make events to control it over time.

Paul__B

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.
It's called telephone cable.

Paul_KD7HB

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.


Paul

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.
Quality of answers is related to the quality of questions. Good questions will get good answers. Useless answers are a sign of a poor question.

kaseftamjid

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?

wvmarle

What you need is 2xNAND gates as SR latch configuration. That's U1A and U1B.

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.
Quality of answers is related to the quality of questions. Good questions will get good answers. Useless answers are a sign of a poor question.

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