Anyone into pic programming?

[HarryM1BYT]

Long ago in a distant forum , someone came up with (but never progressed it) an idea to measure the quantity of water pumped as a means to indicate the contents of the water barrel. They were talking in terms of around £5 for the gadget, which seemed at the time unlikely.

The idea being to have some sort of idea how much water remained in a caravans water barrel, which are usually stored outside of the caravan. Water is pumped up by a 12v submersible pump, the pump controlled either by micro switches on the taps, or by a pressure switch in the pipe in a pressurised system - turn a tap on, the pressure drops, the pump then kicks in to regain the pressure.

Being a bit of a gadget freak, I've been looking at way to implement something similar, but displaying the time the pump has run - A pic to count seconds run of the pump, an LCD display and a reset button would do it. Even better would be something which interpreted the seconds run to a 100% down to 0% level. Not as good as measuring the amount of water which has flowed, but there you go.

Has anyone any experience of pic programming and could write the firmware?

[uk_dave&gill]

I know it's not what you were asking, but I have seen on caravan forums that someone was going to make an indicator device.

Just done a search and found that he was setting a site up to sell these, at

aquabuddi.moonfruit.com/

There is no site there at the moment, but there is an email address, so he might be able to help!

[Dakta]

I do a lot of pic programming, my l-series vnt turbocharger was controlled by two

[HarryM1BYT]

Originally Posted by Dakta

I do a lot of pic programming, my l-series vnt turbocharger was controlled by two

Fancy having a crack at it? There is no money to be made out of it at all (probably), just an interesting project.

It would need to count time running up to a maximum of around 15 minutes, but count it in seconds so 900 seconds. So a display reading 999 down to 0 would be good.

Thinking about it, the 100% down to 0% could maybe be calibrated by an R/C oscillator instead of using seconds, with a ten turn pot to set the calibration up to the barrel size. That would make it user calibrate-able.

[Avulon]

Well, I can't see a PIC version costing less than this meter

http://uk.ebid.net/for-sale/59077987...FczHtAodjCoAew

But if determined to go that route then maybe this

http://www.hobbytronics.co.uk/yf-s20...FQXmwgodug4AKA

With an arduino uno or raspberry pi compute module and an lcd display would be enough to build your own. However unless someone basically writes the software and assembles it for free it'd only be a diy option.

[HarryM1BYT]

The first would offer no useful information, far to large a resolution - my barrel is only 50L and mine is larger than most, about 1/10 cu meter of water per barrel.

The second has definite possibilities at a resolution 2.25mL per pulse/444 per L/22222 pulses per 50L.

It would just need the addition of a divider plus pulse counter and display.

[Dakta]

Depending on what your motives are, theres probably something off the shelf that can do the job with little modification, though if you get stuck it is the sort of job a small mcu is ideal for.

[Avulon]

Originally Posted by HarryM1BYT

The second has definite possibilities at a resolution 2.25mL per pulse/444 per L/22222 pulses per 50L.

It would just need the addition of a divider plus pulse counter and display.

I'm glad that got you to thinking about it, a simple decade counter/divider /display driver and lcd might be all you'd need with that. (makes it sound so simple doesn't it).

[Jumper75]

Harry, I could easily write the code for this. My job is to develop controllers for water pumping applications, most of it built around motorola pics.

Your problem with timing it is going to be knowing the flow rate, which varies with size of orifice and battery voltage, also depends on the tank being fully refilled each time. Usually my preferred method for tank level is a pressure transmitter 4-20mA, but as it will need to be in the range of under 0.1bar it would be very expensive.

The best way to measure the flow is to use a vending machine pulsed flow meter, these are a lot more accurate than mains water meters and can measure flows down to well under a litre per minute. All we need then is to count the pulses, do the maths, and flash it up on an LCD.

Or you could measure the water level using the SR-04 ultrasonic module, very cheap and has it's own driver circuit.

You know there are already plenty of devices out there to measure low volume water flow, ebay is full of them, targeted at aquarium users.

[Avulon]

With some hacking -

http://www.ebay.co.uk/itm/3-x-Digita...item2eddec1e41

Once you know the total count of a full water barrel, you'll be able to tell the remainder from the total count of 0.25ml pulses Just wire the pulse counter to operate the switch electrically (via a transistor buffer) and voila! counts up to 99999, you only need it to count to 22222 so you know 11111 is half empty... Just remember to reset it when you refill the barrel.