DIY Capacitive tank sensor - Page 6

FW28z · 04-24-2015, 10:26 PM

Quote:

Originally Posted by JamieGeek

Some displays allow you to upload your own font (granted that would take a lot of time designing your own font..perhaps you could design your own "T" and only use that font for that letter??)

Looks good.

Yea, the characters are in a 6x8 grid, and you can turn every pixel on and off, so it is certainly possible to do. Perhaps I might work on that.

However, it has been my experience with working other Arduino projects that you can use up all of the available RAM in just screen manipulation.

FW28z · 04-24-2015, 11:09 PM

Actually I ended up writing a simple function to write a "t" anywhere on the screen by passing it x,y coordinates.

I also wrote a function to display a bell... presumably for a channel that alarms when a threshold is reached. The bell is a sub-character of the Black tank's "B".

Finally, I put a "tic" mark to the left of the graph when the bell is active showing the threshold point (at the 75% full mark on the Black tank).

If the alarm goes off, I probably could strobe the bell on and off.

Looks even better.

JamieGeek · 04-24-2015, 11:29 PM

You're getting there. Looks good.

FW28z · 04-24-2015, 11:38 PM

Hopefully Murphy's 7th law will not apply...

You can improve on something only so much, then you break it.

JamieGeek · 04-24-2015, 11:44 PM

Quote:

Originally Posted by FW28z

Hopefully Murphy's 7th law will not apply...

You can improve on something only so much, then you break it.

Thats why its good to have configuration management software..just go back a rev. (Personally I've been using git.)

blw2 · 06-14-2015, 02:53 PM

fw28z, did you ever get around to trying those horst tank probes?

FW28z · 06-14-2015, 03:41 PM

Quote:

Originally Posted by blw2

fw28z, did you ever get around to trying those horst tank probes?

Yes I did. They work a lot better now. I might not upgrade my monitor system.

aetherz · 11-05-2015, 07:17 PM

Quote:

Originally Posted by FW28z

Hi, I was at a garage sale and there was a box full of bundles of these things, they had been donated and the guy had no idea what they were.

I took one home with me to solve the mystery, I first thought I might mess around with my ohm meter, but instead I decided to just cut the sucker open.

Sure enough, a 120k and 68k 1/4w resistor, acting like a voltage divider.

But I'd like to go back to the guy with a specific name and use, can you help me out and tell me what this thing is called, and to whom it might be useful?

Hey, I just used whom correctly and non-ironically, woo!

FW28z · 11-05-2015, 07:19 PM

I would call them a RV Tank Probe harness.

bevedfelker · 11-05-2015, 09:49 PM

Man -- you guys! Just read this thread and I felt like a dog watching television

JamieGeek · 11-06-2015, 12:14 AM

Quote:

Originally Posted by bevedfelker

Man -- you guys! Just read this thread and I felt like a dog watching television

Don't feel too bad: I still have yet to test it and now it won't be until Spring before I get a chance to fully implement it.

FW28z · 11-06-2015, 10:05 AM

I have not done anything with my tank project since April... well almost nothing.

I did buy a spare Kib monitor panel circuit board that I will try to modify to fix the inaccurate LP gas sensor reading (the tank and panel read about 25% different).

I think I can simply remove a resistor and insert a potentiometer in it's place to give me some adjustability for the tank reading. It just bugs me that the tank readings are so far off from each other.

But the major reason (other than enjoying the summer) is I have been working on a "Towed Vehicle Monitor System" that I have been testing since early August. More on that later as I am almost done with the prototype.

aetherz · 11-15-2015, 09:00 AM

Quote:

Originally Posted by FW28z

I would call them a RV Tank Probe harness.

Does this component somehow sense the level of water in the tank (with just resistors in some putty stuff)?

JamieGeek · 11-15-2015, 12:33 PM

Quote:

Originally Posted by aetherz

Does this component somehow sense the level of water in the tank (with just resistors in some putty stuff)?

Yes: Each end connects to tank "probes" (just bolts through the side of the tank). When the liquid level reaches the bolt it effectively shorts that bolt to the bottom one (which is usually ground). Each probe has a different resistance value and the meter can measure the amount of fluid in the tank based on the total resistance of the harness. (Simplified explanation, a more detailed one is a few pages back in this thread.)

aetherz · 11-15-2015, 08:09 PM

Quote:

Originally Posted by JamieGeek

Yes: Each end connects to tank "probes" (just bolts through the side of the tank). When the liquid level reaches the bolt it effectively shorts that bolt to the bottom one (which is usually ground). Each probe has a different resistance value and the meter can measure the amount of fluid in the tank based on the total resistance of the harness. (Simplified explanation, a more detailed one is a few pages back in this thread.)

Thanks.

Well, if anyone wants hundreds of these things, just ask..... (just the red KIB 'harness ' thing)

Paul_Leslie · 01-09-2017, 04:52 PM

Our black tank monitor is either at 3/4 when empty or full. Use the tornado overtime and put soap in periodically.

At nuclear plants when radioactive resin is sluiced to a HIC for disposal, water is maintained above the resin to prevent "pyramiding". Same reason we put water in the back tank after dumping. One of the vendors used an ultrasonic monitor to measure the level of water in the HIC, along with a camera to monitor. Not advocating a camera.

Wonder if a cheap ultrasonic is available?

JamieGeek · 01-09-2017, 05:59 PM

Quote:

Originally Posted by Paul_Leslie

Wonder if a cheap ultrasonic is available?

Looks like Digikey has some for <$20 or so. Looks like a couple of ports would have to be cut into the tank for the transmitter and receiver though--not sure if I like that idea.

Paul_Leslie · 01-09-2017, 09:32 PM

Jamie, the one we used only went in the top. If I remember it was about 4" high. Not sure about the clearances above the tank.

blw2 · 01-10-2017, 01:40 PM

In a previous life, I worked with chemical feed system in the paper industry, and we did a lot of work with tank level sensing, various sized tanks, some smaller but most from around 150 gallons up to around 3,000 gallons. It's been more than 10 years so no doubt tech has advanced, but back then the ultrasonics had issues and we didn't use them a lot. If I recall correctly (and my memory is a bit fuzzy on the subject), one issue was that they worked best with a greater distance looking down to the liquid than we had to work with. Some of our tanks had agitation, & I think other issues were difficulty with that agitation and foaming. At that time the things were improving and looking good though.

Anyway, I am certainly not sure, but I'm thinking that ultrasonics might have issue with the small tank dimensions that we are talking about here....

JamieGeek · 06-10-2017, 12:55 AM

Revisiting this: Nope haven't installed this guy. I have all the circuitry coded, soldered and ready then FW28z sends me a link to this:
https://create.arduino.cc/projecthub...fdc1004-9333c7

Hmm real circuitry designed to perform that function--instead of real DIY as in Design.

A handy truck showed up today containing that breakout board, another arduino, and a bluetooth module for the arduino.

Thus for version 2 I plan on using the above sensor and simply write an Android app to read the levels (easier to write software than to run a wire from the tanks to the panel and install a display ! LOL).

As a bonus the sensor has multiple inputs so I can monitor both waste tanks.

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