Stick-on Holding Tank Level Sensor

[Holding Tank]

HOLDING TANK LEVEL SENSOR; As a hobby (I am a retired radar scientist), I am trying to invent a radar based stick-on battery powered (1 yr) holding tank level sensor with a Bluetooth smartphone readout). If you have interest or have ideas for features, submit a comment.

[peghall]

Not to rain your idea, just some "points to ponder"....

I can't see any advantage to a battery powered sender over already available systems that use external senders that connect to the vessel's DC power supply and draw only milliamps.

The industry warns against using battery powered household CO detectors instead of marine versions designed to be "hardwired" to the boat's power supply because people are too prone to forget to replace batteries in devices that are readily accessible--also highly visible--in the cabin. it's even more unlikely that they'd remember to replace batteries on a tank that's out of sight/out of mind in the bilge or under a settee or berth.

However, IMO an add-on to existing systems--perhaps those with internal probes as well as external senders--but one that wouldn't require its own battery, that would allow the level in the tank to be checked via a cell phone app would be very cool and something tank level mfrs would jump on.

Just my $.02 worth...

[a64pilot]

If it works, cost less than maybe $200 I'm all over one.
Battery isn't a major thing to me, if it doesn't work, I'll change the battery as long as it's not some hard to obtain battery, unlike a CO or smoke or high water alarm, those you won't know a battery is dead as you hopefully never use it.
But I'd really like to know how full my tank is, currently I'm reduced to tapping on the thing and guessing

[Holding Tank]

Thanks for the comments. I know that positive and negative advice is ALL valuable. Lessons learned are the key.

[Holding Tank]

As an old radar scientist, I know I can do it. (and cheaply). Based on advice, it seems that the smartphone app should tell you if the battery is getting low. Remember, it is not a safety issue where an alarm sits there until a fault occurs. You push the "check tank" button on the phone and it says "ooops sorry, battery too low".

[Spindrift NH]

I like the idea. Sounds like an easy install for a non-critical instrument. I'm currently looking at tank guages and like the idea of the external sensor.

[Monepit]

I agree. Battery is not an issue. Unlike a safety alarm, you will use it every day. If it doesn't work replace the battery. I like it.

[Moody46CC]

I think it is a good idea. Stick-on sensors exist now for fiberglass and plastic tanks but not SS or metal ones, and, of course, they are not hooked to smart phones. I think they work on the basis of resistance to an electric current, which prevents use in metal tanks. Radar should not have that issue. And to have it on the phone with a battery warning--good.

[Nicholson58]

I use sticks with notches carved on that correspond to actual gallons in these odd shaped tanks - water and diesel. All of our 9 tanks are 3/16" SS welded. I gave up on the electronic sending units- too many to keep up with. Dowels are really cheap and seem to be reliable. So far, no failures.

[SeaSon]

What about the propane tank stick on strips. Do those work? For water and fuel tanks?

[captstu]

I installed a commercial capacitive foil stick on sensor on my holding tank last week. About $45 and it works perfectly - with a readout at the head. Nice idea - but taken.

[Moody46CC]

Captsu

What material is your holding tank made of?

[rwidman]

Hard wired systems with stick on sensors for non-metallic tanks are already available. They don't work with a telephone, they work with a series of LEDs to indicate the level of liquid in the tank.

I have such a system and the potable water part works just fine. The holding tank part does not because sewage clings to the inside wall of the tank and fools the sensor into thinking the tank is full when it is not.

This can be fixed by cleaning the inside of the tank but this only works until the tank is filled again.

Personally, I don't see any advantage in having this system connect to a phone but I suppose some folks might.

[Moody46CC]

rwidman,

My potable water gauge works just fine. The holding tank uses a WEMA system with a floating sensor suspended in a cage going up and down with the effluent level. The effluent likewise causes it to stick, and yes, it can be cleaned, but .... not too much fun and entails removing the sole and then the 7-8 screws holding the sensor (tightly) in the top of the tank. A lot of work, so any stick-on system system that works properly with a gauge or phone app is welcomed.

[PeteHalstedc]

With others, not sure why it needs a battery instead of just using the 12 volt that is likely already in that area. Having battery as option would be good I guess, but I would definitely want a hardwired option.


Also the mobile app should have an option to setup a check on a schedule and a configurable alert value. That would be one of the real advantages to have a smart phone app version.

The push to check versions are great, but require you to check it. If I had a smart phone app that was checking it twice a day and giving me an alert when the tank reaches a certain level, that would be fantastic and one less thing to think about.

Don't forget the configuration needs to work both ways. Fresh water you want to know when the tank drops below a certain value. Holding tank you want to know when it reaches a certain value.

App should also have configuration for conversion, so you radar unit can tell tank is at 30%, if I can configure the app and tell it my tank is 100 gallons, than app can tell me 30 gallons instead of 30%.

In case you haven't guess by now, I am a software developer so have lots of thoughts and opinions on software interfaces