Tank gauge question

[rowejd10]

I have a 1976 Sovereign that I am doing a shell off. I got it back last November and have worked off and on since then. I have the shell off, the frame repaired and am getting the tanks back in. All plywood is cut and ready to go back down but am getting tanks and wiring in the frame first to minimize working under the frame. I have axles on order so hope when they get in I will be ready to put the shell back on the frame. This forum has been such a blessing on research. Everything i have searched for I have found answers for except for the gauges for my fresh, grey and black tank.

Here is my question: I do not have original gauges for the tanks. I have put See Level gauges on both of my other campers and really like them. My problem is the grey water tank is only 3.5" tall. I think the smallest the gauge can be cut is 4". What have other's done about new gauges and sending units?

I have searched and searched and haven't found a good answer on what gauges people are using or how they worked around this with See Level?


Thanks,
Jimmy

[rmkrum]

Is there room to stick the cut to 4” gauge to the tank at an angle such that the whole length of the sensor is on the entire tank side?

[rowejd10]

Not sure if there is room and not sure what it would do for the sensor to not be vertical. I think I am leaning toward using the see level and making the sensor work. We will get use to however that tank reads. Consistency I have always in those gauges is better than what I hear on existing sensors.

[andymeyer]

Anybody willing to see what the signal looks like on these gauges? I want to use them with a raspberry pi or Arduino, but need to know what the signal looks like... Any ideas? Are these capacitive and the capacitance varies based on tank level? Serial data signal? Something else?

[andymeyer]

You “should” be able to put the sealevels at an angle.

I just got my Arduino gauges working, but need to prove them out... large copper tape pad (6”x6”) on the side of the tank, use the bottom sensor, and use a capacitance measuring code to see how full the tanks are. I’ll show it off once working...

Andy

[rmkrum]

Oh, please do keep us posted.

Have Arduino, will code for food...

[andymeyer]

Rmkrum,
I'm learning python with my son (7), but by no means am I a coder. I started using tkinter for the graphics, but it looks like a bad 80's computer graphic. Any suggestions for making good looking user interface? I can send my code over if you're interested...
Goal is to track the tanks, indoor and outdoor Temps and humidity, control the furnace (thermostat), show power consumption / voltage / amps on the batteries / 120V system. What else would be cool to include?

[rmkrum]

I can offer some general concepts for the interface:

1) provide a dimmable or turn off the display backlighting if possible until touched. Nothing worse than a bright night light of a display in a dark trailer.

2) group functions under one easily readable (big font and high contrast) touch point or button. Make the touch area big enough for clumsy, fat fingers.

3) always include a clear way back to the main menu set at all other places in the menus.

4) group data logically and clearly within a sub menu.

5) provide a set-up menu that is easy to find. Consider selectable metric and traditional units (degrees in C or F, volume in liters or gallons) if you have room in the code.

Try a few ideas. PM me for more discussion.

I’m not in easy reach of my Arduino stuff, but I would suggest a color LCD touch display if at all possible.

Also look at the look and feel of some commercial displays. Swipe a few general principles from them.

One of my BIG pet peeves is low contrast and tiny lettering. I wear glasses and am “over mature and then some”. Tiny lettering and weird colors drive me nuts. Consider folks that may be red/green colorblind. They can’t see red on green letters.

[andymeyer]

Here's my 2nd pass at an interface in tkinter. I've thought about replacing the crappy bars with 20 images showing a tank from empty to full and I just select the right image to display based on tank level...
If you want to see my source and have fun... You might need a couple of beers to make my code tolerable to read though...

[rmkrum]

Actually, I find that quite readable and useful. How big is the display? Details and links to vendors would be cool as well.

PM me and I’ll give you contact information that would let you pass me the code. The beer is already cold.

[andymeyer]

This is a Raspberry Pi 3b+ and their 7" touch screen - available from:
https://www.raspberrypi.org/products/

I plan to do my tank monitoring and electrical monitoring with a couple of Arduino mini's. I've got a handful lying around - inexpensive way to do lots of I/O. Tank monitoring will be done with capacitance copper foil pads I put on the tanks before install... Voltage and current via shunts and voltage dividers...

My thermostat, water pump and inverter will be controlled via a relay module for the Pi.
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Source code... Sent to you via PM... If anyone else wants to see it, let me know. I'm open to ideas! Anything else that would be cool, fun, or useful to put on a 7" screen?