Bite Indicator

[Andrew Leigh]

Hi Duffy

Cool, have double checked, it is seldom that I ever get a circuit connect correctly the first time around so will continue checking.

Found one or two errors and have remedied these, now the LED wont light at all, I will keep checking until I realise what I have done wrong.

The beeper circuit keeps working however. It is odd but the beeper works when you interrupt the opto and, the LED when the interruption is removed. Almost like there are two different channels.

Cheers
Andrew

 

[Andrew Leigh]

Duffy,

got it, with the mistakes I found and the playing around I had also inserted the LED incorrectly. So once these were returned to normality VIOLA.

Thanks a lot the circuit is great.

Now the LED and buzzer activate at the same time not as per my post above. Would like some more gain as the volume is a little thin. I have used a small buzzer, probably a piezzo type 12mm OD and notice on the outside of the casing is states 8k?? Could that be the impedence? When I measure d.c. resistance is is about 990kΩ. Must I get a different device?

Cheers
Andrew

 

[duffy]

A buzzer? That's just suppose to be an 8Ω speaker. A little round permanent-magnet speaker like in a table radio, or a cheap 8Ω stereo speaker, that kind of thing.

 

[Andrew Leigh]

OK,

missed the boat on that one.

Cheers
Andrew

 

[Andrew Leigh]

Hi Duffy,

been experimenting.

I have used a disc with holes drilled around the periphery as a pulley over which the line will travel. The disc travels between the faces of the optoisolator and the holes / no holes interrupt the optoisolator perfectly, the LED responds no matter what the speed of rotation is.

When the rotational speed is very slow the speaker fails to sound, it will only sound when the rotational speed increases. Are there any components I can fiddle with to perhaps improve the sensitivity of the circuit when the optoisolator is being interrupted slowly?

Thanks
Andrew

PS: It's gonna work a treat, the mechanics are going to be the challenge.

 

[duffy]

How slow is slow?

Try disconnecting R6 or C5 temporarily and see if you get better audio response at slow speeds.

 

[Andrew Leigh]

Hi Duffy,

Been messing about.

1. Have tried both options (removed resistor and cap in various combinations) but neither appeared to have an appreciable difference. The speed is difficult to measure but if you interrupt the beam by moving an object slower than about 2mm per sec then she fails to make a sound.

2. Got me a speaker, 4Ω I know you said 8Ω but this is all I have to hand at present. Nice and loud but it stays on all the time and has an annoying growl. I can set the pot to a point where the speaker is quiet but the minute the beam is broken once the speaker stays on.

3. As the speaker was noisy thought I would keep on experimenting with the piezzo buzzer. Thought that perhaps the cap C1 on your schematic may not be needed with the piezzo buzzer so I bypassed it coonecting the buzzer directly to Pin 5 of the LM386 and ground. Progress, now it does not matter how slowly the wheel turns as every hole sounds the buzzer.

The buzzer also it turns out, totally coincidental, has a sound that when the wheel is spinning rapidly it emulates the drag of a reel very nicely indeed.

The only problem with the buzzer is that when the wheel is turning slowly the buzzer volume is low. It is almost as if the velocity at which the beam is broken has some outcome on the volume. There are two volumes, soft and loud.

I blew the original LM386N-1, I had a different LM386 to hand which responds nowhere like the original component. The latest LM386 is nowhere as "clean". Where I was getting no signal when the beam was interrupted I now get a soft feedback squeal?

Any thoughts?


Cheers
Andrew

 

[duffy]

Nice and loud but it stays on all the time and has an annoying growl. I can set the pot to a point where the speaker is quiet but the minute the beam is broken once the speaker stays on.

Probably "motorboating" because of the 4Ω speaker. That's probably why you burned out that other chip - I said not to use 4Ω speakers!

moving an object slower than about 2mm per sec then she fails to make a sound

Whoah, two millimeters per second? So like it would take about 12 seconds to move an inch, right? Over a minute to move five inches? That's very VERY slow. Are you sure this is a disadvantage? Seems like that slow a motion wouldn't be a live fish on the line, might not even want it to make any noise.

Anyway, that's not a problem with the circuit, I just had no idea you wanted the motion that slow. What's happening is the rise time on the opto is too slow for the amp.

If you want to make it work at those super-slow speeds, you will need a comparator with hysteresis to speed up that signal. Fortunately, for this circuit it's an easy fix. Get one of these guys -

https://www.fairchildsemi.com/ds/CD/CD40106BC.pdf

And insert it like in this diagram. Give it +9V and ground on Vdd and Vss, respectively, and tie any of those unused inputs to ground. The 40106 will give a "snap action" response to slow moving signals, and it runs off anything up to 15V.

 

[derrick]

<P>hi Duffy</P>
<P>&nbsp;</P>
<P>let me introduce my self, my name is Derrick from Asian, Malaysia, Penang</P>
<P>I am very interested about the fish bite alarm/Led indicator.</P>
<P>My electronics skill can say ok</P>
<P>About using pc mouse is better compare with photosensor like omron.</P>
<P>cost is no problem , only can build with my self.</P>
<P>what is your advice.</P>
<P>What you recomemd on the box casing to use.</P>
<P>&nbsp;</P>
<P>this is my 1st time using this website.</P>
<P>i am not sure i can communicate you this page or not</P>
<P>My email derrickwth@gmail.com</P>
<P>&nbsp;</P>