Which transducer on the PING module....

deno

from Parallax is the transmitter?· (Looking at the front of the board with the two transducers looking back at you and the header on the bottom.)

By the way, it is possible to "shot" the Ping module into a 3 inch diameter PVC pipe with varying water levels·and get a very accurate return results of how far down the water is.· Pipe is 48 inches long and I can get consistant results all the way to the bottom.·


Thanks...Deno

Ken Gracey

Deno,

Not sure, but I copied this thread to the Ping))) engineer so perhaps he will reply.

Are you asking a question about shooting Ping))) down a pipe to water, or telling us it works? Two of our guys are looking into the different ways to use Ping))) to measure water depth, as it's been a super common question lately on the forums. We plan on producing some recommendations out of our research with diagrams and possibilities/considerations.

If you've already tried this, tell us about your results because we're very interested.

Ken Gracey
Parallax, Inc.

deno

Yes...I have been working on determining how much water I have in my water tank on my boat, then displaying it on a Scott Edwards LCD, amoung other things, like the flow rate out of my watermaker, and the Total Dissolved Solid of the water being made. (Under 500 PPM is drinkable)

I started out with a 2 inch PVC pipe, but I seemed to be getting an occasional bad reading.· I determined that I was getting a false bounce (believe it or not) from left over water drops clinging to the side of the pipe several inches above the actual water level.

Let me explain my setup.· I sized up to a 3 inch PVC pipe, (to try and avoid the above problem...I think 4 inch PVC pipe would work better) that is 48 inches long.· My water tank on the boat holds 270 gallons of water, and is 37 inches deep.· If you do the math, that is 7.3 gallons per inch.· So even with integer math, it is simple to compute the water level in the pipe to "Gallons remaining in the tank".

· PULSOUT level_sensor, Trigger····························· ' activate sensor
· PULSIN· level_sensor, IsHigh, top_of_water_dist······ ' measure echo pulse
· top_of_water_dist = top_of_water_dist */ Scale······ ' convert to uS
· top_of_water_dist = top_of_water_dist / 2·············· ' remove return trip
· gallons_of_water =· ((empty_dist_uSec - top_of_water_dist) * 10) / 98

· 'The * 10 and the 98 comes from...9.8 uSeconds per gallon of water

Explaining my pipe setup further, after glueing a 3 inch PVC pipe cap to one end (bottom of pipe) I drilled and tapped a 1/4 NPT hole at the very bottom on the side of the pipe, and another one at 37 inches up, and connecting the holes with a 90 degree 3/8 inch...1/4 inch MPT fitting ·and clear hose.· This way, with a yard stick glued to the side of the pipe by the hose I can "see" how much water is in the pipe to compair the PING))) readings to.· This pipe will be secured in the engine room, next to and at the same level with the exsisting water tank, and fed with a 3/8 inch hose to the bottom of the pipe, thus showing the water level in the main tank, both with a visual indicator in the engine room, as well as a electronic indicator (using the PING))) at the helm station.

I secured the PING))) inside a 3 inch PVC pipe cap that slips down over the top of the pipe and will always "seat" to the same spot making sure the PING))) points straight down.· Now my concern is finding a plastic material (maybe food wrap) that is thin enough to "shot" thru and at the same time protect the PING))) from any moisture inside the pipe.· Maybe there won't be a problem, as it is mounted 11 inches above the highest water level.· I did install a overflow drain hole at 38 inches.

Sorry, for rambling on...if I gave to much info for this part of the forum.· Maybe some of you will be interested.· Buy the way, I am only using a BS2...

Deno

Post Edited (deno) : 7/17/2006 12:11:19 PM GMT

Chris Savage

Deno,

·· While we look into this further, the fact that you have already had water droplets on the smaller diameter pipe means you have moisture, which can adversely affect any electronic circuit directly exposed to it.· During experiments I am going to try and determine if srink-wrapping the PING))) (except the transducers) will work okay, since the heat-shrink will be in direct contact with the outside of the transducers.· I don't think it will affect them any, but we'll test that.· BTW, good job on coming up with a working solution.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Chris Savage
Parallax Tech Support
csavage@parallax.com

deno

To clarify the "water drops" on the inside wall of the PVC pipe.· If I release the water slowly (as would happen on the boat as the tank level goes down from doing dishes and showers, etc) the water drops don't seem to form on the insides of the PVC pipe.· If I release the water all at once or a fast rate, then the drops "cling" to the sides of the pipe.· The "water drops" are not from condinsation, and there is no water getting on the PING))) sensor.

My next thought is to coat the inside of the PVC pipe with a thin layer of something???· I have some very thin sheet foam, closed cell, that I can make a tube who's OD will allow it to slide into the 3 inch PVC pipe to act as a echo absorber of sorts.

Maybe this and the other posts belong in the Sandbox forums?· Move them if you think necessary.

Deno

Chris Savage

Deno,

·· The forum is fine...We are actively looking into several things on the PING))) sensor following your post.· One question that has come up here, is whether or not the top of your tube is sealed?· Did you mount the PING))) on the bottom of a cap?· How is it mounted to the tube?· Thanks for your input.· We will report back any results we have.· Right now we only have a 36" piece of PVC, but we're getting a 4' section tomorrow.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Chris Savage
Parallax Tech Support
csavage@parallax.com

deno

I have taken a couple of photos to help show how I mounted the PING))) in the cap.· Hope they will help explain.

Post Edited (deno) : 7/17/2006 6:19:25 PM GMT

Chris Savage

Deno,

·· It looks like your tube is not sealed, but rather vented?· Is that foam at the top.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Chris Savage
Parallax Tech Support
csavage@parallax.com

deno

Yes, you could say it is vented and I purposely did not seal or glue the cap on.· I want to be able to remove it incase I need to do something with the PING))).

There is no foam, at the top to seal with either.· The PING))) sensor IS sandwiched in place with foam and a piece of PVC to keep it from moving.

There is no need to seal the top in my case, as the PVC pipe will be mounted vertically in the engine room.· Yes, the boat will roll from side to side, but never past 15 to 20 degrees in a beam sea way.· Plus, I did install an overflow fitting at 38 inches so as not to flood the PING))) with water.

The PING))) will not shoot thru plastic sandwich wrap.

I haven't install this device on the boat.· Still testing in the garage.

I tried to download a third picture of the whole PVC pipe project, but the computer on your end (or somewhere?) kept timing out and would not take the· final download.

Deno


Post Edited (deno) : 7/17/2006 7:36:27 PM GMT

Chris Savage

Deno,

·· Yeah, you can't have anything in front of the sensor as it will block the signal.· I kind of figured your tube was vented or water wouldn't be able to rise in it.· I will let you know what additional information we come up with.


▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Chris Savage
Parallax Tech Support
csavage@parallax.com


Post Edited (Chris Savage (Parallax)) : 7/18/2006 2:57:35 PM GMT

Jason-WI

To protect the Ping))) from moisture you could conformal coat the PCB front and back. I would not get any conformal coat on the inside of the transducers as that would most likely render them useless. Applying contact grease on the 3 pin terminal will prevent the pins from corrosion.

Jason

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
He who dies with the most toys wins!