I have a 100 ft weighted tape line that goes down a water well to check water level. I really need to fix a simple compression close the circuit and beep circuit to the end of it. When it hits the water it closes and beeps ...the steel well casing will carry the sound up efficiently.
do you know a simple circuit I could buy that will do this???
I have seen the mini cams that are available now but the longest cable I have seen on them is 50 ft. I need at lest 100 ft.
thanks.

 

Sewer cams typically have 200 ft cables, but they aren't cheap. Here's the first one that came up:

https://www.toolexperts.com/sewer-camera-video-dvr-drain-scope-pipe-inspection-viztrac-am240.html

If you can use a camera effectively enough to justify the price, problem solved.

Otherwise, it would be a simple matter of making a battery powered buzzer unit that had the sensing element a few feet down from it (so that you can try to avoid submersing the unit itself). The sensing element can be just a couple bare wires that the water provides a conductive path for. I would expect the water in nearly any water well to have enough dissolved mineral content to be sufficiently conductive to sense. The longer the wires, and the closer they are together, the lower the conductivity of the water can be. Very easy to test using a cup of water from the well.

 

do you know a simple circuit I could buy that will do this???

This should work.
https://www.walmart.com/ip/First-Al...6705:pla-56543428369&wl5=9028764&wl6=&wl7=901
SG

 

How about a float switch?

 

I'm not a huge 555 fan, but the CMOS version (LMC555) is a good fit for this. The Reset input current is 10 pA, so if it is boased with a 1 M resistor it will make a suitable moisture sense input.

LMC555
2 resistors
3 capacitors
1 piezo beeper
1 - 9 V battery
1 waterproof container - smaller than a tennis ball

The beeper can be a piezo element that beeps continuously, or a self-contained type that beeps once per second (more attention-getting).

We don't know your skill set. Does this sound like something you can handle?

ak

 

I like the 2 wire idea..... but there is a lot of sidewall moisture also on the way down...I was thinking a spring loaded contact, a light spring to close the circuit. It would be good if I could just buy one off a hobby site...there are some
excellent 35$ cams now on Amazon...could I make a 100 ft cable??or buy one that would work?

 

like a small float switch but not a big one..

 

How about this. A small plastic waterproof container like a small cylinder, maybe 2" diameter and 3" tall. Small magnetic reed switch glued to the inside bottom. Switch turns on battery and beeper circuit. On the outside bottom of the container is a very small hinge with a small magnet on a short lever, like a piece of Popsicle stick. When the bottom of the container is immersed, the wool floats up against the bottom of the container, placing the magnet next to the reed switch, turning on the beeper. You can buy a steady-state or pulsating beeper and eliminate any electronics.

If the wood is not buoyant enough, add a small piece of packing popcorn.

Update: Note that with a self-contained, battery-powered circuit, what is going down the tube is a single string - no wires (unless you want to use wire for its dimensional stability).

ak

 

I like the 2 wire idea..... but there is a lot of sidewall moisture also on the way down...I was thinking a spring loaded contact, a light spring to close the circuit. It would be good if I could just buy one off a hobby site...there are some
excellent 35$ cams now on Amazon...could I make a 100 ft cable??or buy one that would work?

May ways of tackling the problem. The sidewall moisture can be dealt with by simply enclosing the sensor in a length of PVC (or other insulating) pipe that lets water flow in/out the top/bottom easily. If the sensor is low enough impedance when immersed you could use it as the power switch to a pre-packaged buzzer module so that all you need is the buzzer, the battery/holder, and the sensor. No moving parts.

 

Use @WBahn's PVC pipe with a wine bottle cork with a round magnet attached to top. Outside attach a reed switch. Add a Mallory SONALERT & 9 V battery.

 

Use @WBahn's PVC pipe with a wine bottle cork with a round magnet attached to top. Outside attach a reed switch. Add a Mallory SONALERT & 9 V battery.

This is what I had in mind when I initially suggested a float switch. Nice.

 

First, get three 555's and an Arduino. then ...

 

This is what I had in mind when I initially suggested a float switch. Nice.

I’d put a cotter pin at the bottom of the tube to keep the cork in place. And I’d drill/cut holes in the top of the pipe to reduce back-pressure as the cork rises.

 

As I already had some short sections of slotted PVC, ID = 20.7, OD = 26.7 X 84 mm ( 5 gal. bucket handles ), heated & stretched with wood rod to 23.65 mm ID to allow artificial cork, 20.9 X 38 mm to slide freely. Took a round magnet from refrig. 18.2 X 5.2 & placed it on top of "cork". Taped a reed SW near top of pipe, monitored with ohm meter. Raised & lowered in a cup of water with no misses. Artificial cork did not stick to sides as real cork did. A heavier magnet or some non magnetic weight added would help. Encase SW in plugged tubing. All measurements in mm.

 

good ideas thanks
I will look at the sonnet item