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time delay

alexandrer

Jul 15, 2014
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Hello

I'm new in this projects so probably what I need is not difficult, but when you don't know ...:D

I'm doing a fishing sea bite detector.
It's quite easy, I'm using two 3v battery, a vibration switch, a resistor and a led.(in this project my space is very limited)

It's working well detects the movements of my fishing rod all the time :(, when is fish, wind, waves, and this is the problem.

For example the wind gust and the waves do the led flashing normally one time or two when they catch the line, and after that the led is off, but when is fish the led is keep flashing.
What I want is when is not fish the led don't turn on.

To resolve this I though in putting something that just allow the current to flow if the vibration switch is on for more than 3 seconds, for example, this way when the wind gust or the wave catch the rod line the led doesn't work, if the movement of the fishing rod continue for a certain time, it allows the current to flow.

Any ideas how this can be done?

Thanks
 
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Gryd3

Jun 25, 2014
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Perhaps a different sensor may be required?
Sounds to me that the switch is too sensitive, you can try moving it further down the rod closer to the reel where it will not vibrate as much. Keep in mind though that the fish will need to jerk on the line to make the switch vibrate, but this may not be an issue with larger fish.
I'm hesitant to introduce a delay, as the fish would need to continually shake the rod by tugging on the line to trigger your event.
 

shrtrnd

Jan 15, 2010
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Check-out Time Delay Relay, and see if that will do what you want.
Consider the 'Delay- ON' type.
 

KMoffett

Jan 21, 2009
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I first thought of retriggerable monostable 555s and diode logic, but then thought better would be an 8-pin microcontroller. Small size. Compatible with the batteries. Low power. Can use programmable logic and adjustable timing to set the delay time.
Ken
 

Arouse1973

Adam
Dec 18, 2013
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What about a Frequency to voltage convertor. This might allow you to detect the difference between slow movement from the wind and fast movement from the fish.
Just a thought
Adam
 

Gryd3

Jun 25, 2014
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Depending on what he's trying to catch, many fish won't continuously shake the rod.
This makes detection from the frequency kind of difficult. A small nibble on the hook may cause the rod tip to move differently as well which could yield false positives for many methods.
Typically the end of the rod will bounce a little bit differently, and you'll notice more tension on the line. To help keep the circuit simple, it may be best to either swap out the sensor for a less sensitive one, or move it further from the tip of the rod where it is less flexible and thus will not move as much. (Allowing the sensitive switch to be used). This setup would only light the LED on the initial, or following harder tugs from the fish. You will most likely need to adjust sensitivity based on the size/weight of the lure. Set your line, with the sensor at the tip of the rod (which will go off too often) then slide the sensor further from the end until you no longer get false readings. (Test it with a gentle tug on the line/rod to make sure it is still sensitive enough)

If you want to add more advanced features, look into using a latch to hold the output to the led high for a couple seconds. (As ideally, the switch you are using will only be closed or activated for a fraction of a second each time the line is tugged). You can also look into the microcontroller suggested by KMoffet which will allow you to preset how many 'jerks' of the rod are required within a given time to trigger the LED (and/or buzzer ;))
 

Arouse1973

Adam
Dec 18, 2013
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How do you deal with the problem of wind which he mentions in his original post?
Adam
 

Gryd3

Jun 25, 2014
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How do you deal with the problem of wind which he mentions in his original post?
Adam
Mainly an assumption, but the rods would be mounted in holders on a boat or on a dock. With the sensor mounted further from the tip on a portion of the rod that is stiffer, the sensor (even a sensitive one) will not trigger in the event of direct wind, or movement of the boat due to wind. (This would require the sensor to be securely mounted to the rod so that it does not move independently of the rod, which would cause false positives)

If you need to measure the weight of a 150lb person, but you only have a sensor rated to 50lb, you can use plank. Place the plank with a brick on one end, and the sensor at the other, the have the person stand 1/4 of the distance from the brick.
End end up with a lever that will only put 1/4 of the persons weight on the sensor allowing it to be used.
I'm thinking of the same idea with the rod. The tip moves much more easily and freely compared to the handle which in theory will not move. (With exception to boat movement) If the sensor is too sensitive, move it closer to the handle ;)


Edit: if the sensor is too sensitive... vibration from the boat and other sources may trigger it as well... In this case I can't see any of our solutions working. Alternatively, if the rod rocks back and forth in the cradle from the boat motion or wind, that could also be a problem for my suggestion and would complicate the frequency to voltage solution.
 
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Arouse1973

Adam
Dec 18, 2013
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Ok if you cant tell the difference between the bell curve response of wind then what about a strain gauge. That will tell you how much the rod is bending.
Adam
 

Gryd3

Jun 25, 2014
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Ok if you cant tell the difference between the bell curve response of wind then what about a strain gauge. That will tell you how much the rod is bending.
Adam
Strain guage would be a good idea. Wheetstone bridge and a comparator will detect rod deflection. Too bad the OP isn't more active. If this is a sensor to be used while trolling, the weight and size of the lure would cause lots of gradual deflection as the waves roll by. This could be compensated by reading the change in deflection rather than the absolute value.
 
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