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ESI Project: Water Usage Monitoring

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This project will involve measuring water usage in one of the bathrooms in my house, predominately for teaching my nephew, and possibly others, the value of conservation and efficient use of available resources. Additionally, I hope to implement monitoring the electricity usage in said bathroom as well as my nephew's bedroom in order to expand the lessons beyond what's obvious and into things which are taken for granted; might expand this to the whole house if it becomes feasible to do so.

 

 

Topology:

- Individual sensors with MCU, sensor and power source at each station, transmit data via wireless to central control station where calculations and report / monitoring occur.

 

 

Monitored stations:

- Shower. Individual hot/cold monitoring not required due to those being mixed at the valve.

- Sink. Will require independent hot and cold monitoring due separate valves for each, mixing at the fixture and lack of space at the faucet outlet.

- (future) Electrical: bathroom light, exhaust fan, bedroom light, various outlets, possibly entire house distribution panel, with inductive sensors.

 

 

Sensors:

- Water: to be determined; will update this post as solutions are decided on.

- Electrical: to be determined, likely inductive type; will update this post as solutions are decided on.

 

 

 

Reporting / Display:

- To be determined; I will update this post as solutions are decided on.

- Would be nice to use the LCD peripheral in the FR6969.

 

 

Considerations:

- Powering the devices.

-- obtaining power for electrical monitoring can be done from the AC circuit in place.

-- obtaining power for the water flow sensors will be more difficult but may be possible to generate power from the water flow itself.

- Transporting data:

-- Data will require wireless transmission.

-- Simple transmission of sensor transitions, i.e. 'high' to 'low' with a 'StationID' seems plausible, so that said data can be fed to the ESI peripheral on the remote MCU.

-- Transceiver types to be determined later; considering CCxxxx and nRF24 types at the moment.

- Sensor data processing:

-- Limited MCU resources: 4 ESI modules.

--- Will require some means to switch between sensors since there will eventually be more sensors than ESI modules.

--- Since data will be transmitted wirelessly, buffering data at the remote end and transmitting in bulk is an option. My thought here is the remote MCU 'records' data, then transmits that to the central station where the data is 'played back' into the ESI and interpreted. This should work well with the water flow sensors where flow data will likely be a bit stream from hall-effect sensors, but electrical may prove more difficult as it will probably be analog in nature.

 

 

 

I welcome any comments and suggestions.

 

And thank you TI for providing this opportunity!

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Cool project. I've been eyeballing water consumption monitoring as a project I want to try sometime, so I'll definitely be watching this!

 

On the electrical side there will probably be enough space and free processing power on the MCU that sits in the electrical box (or on the wiring) with the sensors to chew on the data and spit out either a hall effect style "tick" every X watt/seconds (watt/minutes, watt/hours, whatever your units end up being), or send a packet every X seconds saying that Y watt/whatevers have been used. That would leave the ESI bits on the base station free to deal with the water sensors.

My basic thought process is that anything that can run a radio should be able to turn even a basic amps/volts over time sine wave into a digitally storeable / transmittable number in the ~16ms period a 60Hz sine wave gives you. Monitor one full cycle, spend the next cycle calculating, send the data off every 60 cycles. Something like that.

 

I'd love to see water sensors powered by water flow.

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One problem I see with the electrical monitoring is that if the sensor is at the outlet / switch, there's not much room in a standard wall outlet junction box, and not much in a dual / 4-square box either, if both halves are in use. I'm going to map out the breaker panel to verify which breakers go to which outlets / switches and maybe put things in there if there's fairly clean demarcation between breakers and areas of the house. This opens up the possibility to having an FR6969 in there monitoring electricity, communicating with the central station wirelessly. I also want to comply with codes / NEC as much as possible too.

 

We'll see- I'm home alone now so running around the house with the tester, back and forth, flipping breakers and stuff is too much physical exertion for me. ;)

 

 

@@bobnova - I've seen the little LED faucet outlet gadgets that light up the water according to the temperature of the water. I'm going to check if those are battery powered or include some sort of mini hydroelectric generator in them. I think the shower will be the most difficult to do.

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This project will involve measuring water usage in one of the bathrooms in my house, predominately for teaching my nephew, and possibly others, the value of conservation and efficient use of available resources. Additionally, I hope to implement monitoring the electricity usage in said bathroom as well as my nephew's bedroom in order to expand the lessons beyond what's obvious and into things which are taken for granted; might expand this to the whole house if it becomes feasible to do so.

 

 

- Sensor data processing:

-- Limited MCU resources: 4 ESI modules.

--- Will require some means to switch between sensors since there will eventually be more sensors than ESI modules.

--- Since data will be transmitted wirelessly, buffering data at the remote end and transmitting in bulk is an option. My thought here is the remote MCU 'records' data, then transmits that to the central station where the data is 'played back' into the ESI and interpreted. This should work well with the water flow sensors where flow data will likely be a bit stream from hall-effect sensors, but electrical may prove more difficult as it will probably be analog in nature.

 

 

I welcome any comments and suggestions.

 

And thank you TI for providing this opportunity!

 

As far as the microcomputer and ESI module - what is the point/benefit of using the ESI module if you have separate micros, wireless transmission, etc. going to feed them?  When I skimmed the ESI module description (and from summaries posted in the competition thread) I was under the impression that the point of the module was to be able to massage data without waking up the MCU (as a way of saving power).  (Or possibly as an auxiliary processor, offloading tasks from the MCU that are beyond its' abilities.)  Seems like the radios and other micros running the sensor nodes, plus the radio receiver at the central node will be slurping up enough power that it won't make much difference whether the central computer wakes up, or sleeps and let the ESI module handle things.

 

On another note.  Will you also be tracking the resources put into the project?  (Time, power it consumes, parts, embodied resources involved in making the parts, etc.)  Seems like that could be an additional reinforcement of lesson in conservation and effective use of resources. 

Occasionally I have run into discussions of an idea for saving resources where it seems likely that just the discussion of the idea is consuming more resources than implementing the idea could possibly save.  

http://xkcd.com/1205/ 

 

Helpful perspective for such things is to use a rough quantification of how much resources a person uses in living per minute, hour, etc.  Gives perspective on - e.g. if I spend 10 minutes posting on this web site about something, how much energy, water, have I just used, how much waste have I just produced, has the benefit from what I said or learned there been worth/offset the input of resources.

 

I hope this doesn't come across as too negative.  One may of course derive pleasure from a hobby, and prototypes/experiments are part of the expensive prelude to production versions/practical application.  So the intent of my comment is to suggest ways to add to the levels of instruction you can provide with your project, not to disparage.  

 

As far as monitoring the energy use - isn't water heating one of the major energy uses in a bathroom.  (That and space heating to keep the bathroom warm to start with.)  Maybe add those as future work.

Depending on what your climate is like, could also think about monitoring humidity in the bathroom (while you are at it), with an eye towards mold prevention.  (In some climates this can be a problem.)

 

I enjoy reading about various home monitoring systems, (have some ideas about furnace monitoring in my todo list) and look forward to reading about this project.

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@@igor - excellent points you made, and many I hadn't considered. This will definitely require some more thought and planning. But this is the fun part- planning, hitting head against the wall because of bad decisions, more planning... et cetera. :D

 

Regarding usage of resources, I do plan on tracking as much of what I can. But I see it as little different than most other things I do where the prime motivator is me, and if anyone else can benefit from it they're free to do so, or if I have some exorbitant solution that someone may not want to undertake themselves I may be willing to do so for a bit of remuneration.

 

Regarding the water heater, unless I can monitor the gas usage of it and correlate that to where the hot water is going, I don't want to say it's a moot point but it is the least expensive expenditure we have here, amounting to under $10 per month. We have three sinks, two bathrooms with tub/shower, clothes washer and a dishwashing machine. Maybe, if I can get something working well with the current plan, these could be incorporated later.

 

I will definitely be reconsidering the topology aspect of this, and will likely smack my forehead more than a few times in the process. ;)

 

Thanks.

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Check your water pressure first, it says it's rated for ~79PSI maximum and ~65PSI normal operating. That may be plenty, but my house is in the lowlands and runs 68-73PSI, pretty close to the maximum.

 

Other than that it looks perfect, tons of current, plenty of volts.

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Check your water pressure first, it says it's rated for ~79PSI maximum and ~65PSI normal operating. That may be plenty, but my house is in the lowlands and runs 68-73PSI, pretty close to the maximum.

 

Other than that it looks perfect, tons of current, plenty of volts.

 

Nah! The pressure can't be that high!

 

Your water system should be blowing apart at 65 or 79PSI!

 

 

If you inserted a decimal point then I would believe you ie: 7.9 or 6.5 PSI.

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I think I'm going to leverage some things I already have for this.

I have Chronos watches and their associated wireless access points based on CC1101 hardware (I think- 915MHz with white PCB is CC1101, right?).

My computer here is within 30 feet of every water outlet in the house so the range seems adequate.

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@@bobnova @@zeke

Thanks for the information. That wasn't something I'd thought of so I will definitely be checking the mains pressure. However, I don't think it'll be an issue since even flushing the commode drops the water pressure in the shower. Fortunately, that doesn't cause scalding hot water to be released though. If it did, I'd be having a lot more fun with my wife. ... okay, that sounds wrong. :D

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It seemed high to me too, it's on the high end of normal, but within the normal range.

Under ~30PSI is frowned on, most systems aim for 40-60. There's some more data here: http://www.cpuc.ca.gov/NR/rdonlyres/A172EAE5-8520-468E-85D8-67E9BA3FC984/0/WaterSupplyRequirements.pdf page 7 gives some example numbers.

 

If the generator is on the nozzle side of the valves rather than the mains side of the valves you're absolutely correct, it'll never see anything close.

I was thinking of using it on the mains side of the valves, not sure why.

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@@bobnova

Those units, should I go with them would be located ahead of the faucet so they would see full mains pressure. Even if I mounted them after the spigots under the sink they'd still be exposed to mains pressure, and there's no easy, affordable way to reduce the pressure short of altering the pressure to the whole house, and the neighbor's too- I live in a co-joined house, i.e. condo or duplex if you will, so we share the water mains.

 

So the thought was to install two of these under the sink ahead of the spigot / control valve, and therefore before the actual faucet fixture.

 

My nephew broke his $5 MP3 player so I have that battery pack and display setting here, both just begging for something to do. ;)

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Okay, I think I have a plan for at least part of this.

 

Seeing as how one of the units I'm looking at for generating power from the water flow is an AC generator, I'm thinking I can maybe connect them to a MAX9926 chip to get signals from their outputs. Those chips are variable reluctance sensor interface chips which take the AC signal from a VR sensor and output a signal as the AC waveform transitions from positive, through 0 volts, to negative. Since the frequency of the AC signal should vary with the speed of the generator, a little bit of math should allow to work out the flow rate. Only problem I can foresee is if the flow is not linear with regards to the signal, some additional math could be required.

 

post-26656-0-64538300-1410559997_thumb.jpg

 

So things to work out now is the circuit, generating the 5v needed for this chip, a battery to provide power when the generators aren't producing usable current, and the math.

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Starting out slow. Probably going to do a sensor / power board with a processing board separate, mezzanine style.

 

Not sure what I'm thinking now, using through-hole parts though. ;

post-26656-0-07254100-1410928130_thumb.png

 

The idea I'm having with the board above, is to make a "booster pack" like board, with battery.

And a "launchpad" like board with the FR6989.

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