Waterproofing MPX5700AP transducer question

[dave job]

Anyone have any experience in waterproofing an MPX5700AP transducer for use as a depth sensor? I'm not sure if I need to just waterproof the wiring connections, or the case up to but not including the sensor nozzle. From reading the data sheet, I'm pretty sure I need to leave the nozzle exposed to the water, but there's also a small square hole on one of the flat sides of the case that I'm not sure about. Here's a couple of images, the close-up showing the little square hole (red ring around it) that I'm concerned about. Two jpg files attached, first shows entire transducer, the second is a close-up of the square hole on the case (red ring around it). Thanks.

MPX5700AP transducer

transducer1.jpg (64.49 KiB) Viewed 7390 times

Close up of square hole on case (red ring around it)

transducer2.jpg (61.17 KiB) Viewed 7390 times

[rossrov]

Hi Dave. The datasheet says that the AP does absolute pressure, not gauge or differential. Looking at the drawing on the datasheet the port you circled does not appear to communicate outside fluids/gases/pressure to the chip. There is also some stuff covering the other side of the chip to prevent contamination. Based on that if I was using one of these i would coat the wire connections with epoxy or similar and put the whole thing out in the water just as it is. Alternatively put it inside the ROV housing and CAREFULLY connect a pressure tube to the outside. Never used one of these myself so cannot say I've tried any of the above. Hope that helps.

[dave job]

Thanks rossrov, it helps. I think I'll try coating the connectors for starters and then trying out a simple test in the marina here and see how it goes. If that's fine, then I'll just connect it to the rov frame, maybe build a small cage or something around it to keep it from getting banged up.