Fishing YoYo Stop-Motion Switch Circuit with Indicator

The post discusses a stop-motion switch circuit or a strike indicator for aiding fishing yo yo applications. The idea was requested by Mr. Mike.

The Circuit Request

(kindly bear the long discussion) Hello Sir,

My name is Mike. I am the one requesting help with this stop-motion switch from the "Homemade Circuits" Blog page. Your help in this is greatly appreciated and a donation is most definable applicable.

I am working on this project for a customer and I have most of it done but this particular part has me hung up. Once I get this complete, and get paid for it, then I will offer compensation for your time. As it is well deserved.

For the circuit is for a fishing yo yo. Once the device is triggered, the rotation of the line spool will rotate an optical wheel like that in an old ball mouse.

The optical encoder circuit is the first part. The digital output from the encoder will trigger a motion detector that will trip the flash pattern.

When active, the motion will flash the LED yellow until motion stops (the fish fighting on the line stops). When the motion stops, the system will switch from high to Low from the 556 switching the LED from a flashing yellow to a solid green indicating the fish is too tired to fight anymore and can be retrieved from the water with little or no fight.

I have attached a jpg photo of my schematic I have so far. Before spending the money on components, I was wanting to double check the system on a prototype breadboard first.

(The attached file is checked and clean of bugs)

Thank you again.


Sorry to bug, promise I'll keep messages limited. But I had a revision of the original print. Thought with the digital output from the encoder, why would I need a detector to trigger the flasher?

Couldn't I just use the digital output from the encoder to trigger the 556 and remove the detector part altogether?

But with that circuit, would the high side of 556a flash until the threshold switches low to trigger 556b and set the second led to ON until reset?

Then on reset, both go low (off) until signal from the encoder triggers the 556 again? Just double checking my work. Thanks Hello Mike,

Analyzing the YoYo Concept

Your second concept looks fine, you can try a few mods though, replace R3 with a 1uF/25V cap and use a series resistor, may be a 10k in between the collector of 2N3906 to the trigger of 556, this would stabilize the motion sensor output and provide a clean input to the 556 trigger pinout.

Kindly note that I always prefer publishing readers views and schematics in my blog, I won't publish this info in my blog since you don't want it to be, but please remember that in future I would always want them to get public through my blog.

I completely understand. As myself looking for a solution to something like this, I too (obviously) search blogs as well. I will say, that the overall project is under provisional patent and the Utility Patent is going to be applied for the first of October this year.

But the schematic and electronics are only under patent IF used in the same manor as described in the overall design of the device (the fishing yo yo).

All that to say... the schematic, function, and design are open for any other application with no restrictions other than using on a yo yo.

So, please... By all means let the info free! I would have done it myself, but didn't know how. If you can, consider this email as written permission from an authorized representative of the Tyendaga Research Center to edit, print, duplicate, distribute, or anyway use the information regarding the electrical circuitry in any manor within US Legal boundaries and not infringing upon the patented Automatic Night Fishing Yo Yo that you see fit.

In short, thank you for your help and by all means... Publish!

And for the circuit, I get what you're saying. That makes sense. Thank you. I'll get the components this weekend and plug them in the protoboard. If you are interested (I promise I won't bug if you don't want.) I can send you pics of the outcome.

ya, sorry bout the rant. It was late and I was tired. I tend to babble when I don't get sleep. But good enough.

Stop-Motion Relay Switch

The actual title of the original idea for the circuit (what I was looking for) is called: a Stop-Motion Relay Switch". But of course there is no longer a relay so you can use the same title or use a different one. The circuit is not patented unless combined with the yoyo (but you get that I know).

I still don't quite know how to post pics, so would it be cool to just send you an email with them and you can post?? or is there a want that I can that I don't know?

Like I say... you help me, I help you. I think the Barter system is the BEST system ever created! Better than money even... sometimes!

I'll get back with you the first of the week with what I got.


Please check the attached diagram above, I think this will do the job. I saw one serious fault in your design, the 2N3906 did not have a base resistor, I think you might have already blown of this transistor during the testing procedures.

Ra, Rb and C may be appropriately selected for getting the desired flash rate on the LED.

That's crazy, man! how'd you come up with the idea of the second pnp combined with the npn?!? That controls both the reset AND the output! Ingenious! I think that might work. I'll play with that and let you know how it turns out.

Thanks Bro

Welcome Bro,,,,I forgot to include a resistor at pin#3 of 555, please connect a 1K resistor there, else you'll fry the LED:)


Ya, I caught that too. Already plugged one in. But good eye. Taking the day off. Trying to track down another 2n3904 but have some stuff to rip apart to find it. I'll get back on it tomorrow and let you know how it turns out.

BTW... Because you have been such a help in this, I'm including you in the compensation side too. That was the deal, right? So, once I get paid, I will pay it forward.

God bless

Just a bit of correction, the resistor should be across the cathode and ground of the LED and not with pin#3, because we want pin#3 to ground all vibrational signals from the emitter of the NPN transistor every time it goes zero.,

That means now have two resistor in line, one resistor at the collector of the NPN and another at the cathode of the LED, this will 100% fix the matter for sure.

...and thanks very much for considering my contributions:)


Ughhhh! Mechanical Engineering is SO much easier!

Ok. Here's what I got...

Redid the circuit 4 times to double check my work. I only have two parts in question. The 0.47uF capacitor off of Q3 is impossible to find without ordering one.

I used a 0.1uF being the closest one I have. Is there another value that I can substitute? Also, the Detector (Q1) is from a mouse circuit with a 3-pin photo-transistor.

I don't want to blow it out so I left the base open and connected the collector to HI and the emitter to base of Q2 (2n3904). All other values are as spec.

I added a few photos to give visual aid to my work. Maybe you can see something I missed. (note: The led is solid not blinking) If you want video, I can send that too. (There will be another email to this so this is 1 of 2)

PS... Notice the title block of the schematic. I added something. I figured you deserve it. I plan on copywriting this when its done and I will put your name on the copywrite as a co-writer if you're cool with that. I'll let you know how that turns out.



Checking the Final Design

Yes the circuit looks perfect now, but I could not understand the pics, do you mean the circuit isn't functioning?

because with a well defined voltage at 3906 collector the 555 should start flashing the LED.

For the receiver you can use any IR sensor of TSOP17XX series.

As for the reset function, you can do it by adding an additional set/reset stage, along with a spdt spring switch.

The switch would load on pressure and set the circuit into operation, once the fish is caught and removed of the hook, the switch would reset the circuit into off position and switch-off the LED..

I'll try to provide the details through a diagram soon.

You can use 1uF in place of 0.47uF.......0.1uF would hardly filter anything, won't do any good.


This is just an idea, not sure if it would suit your requirement exactly? Referring to the diagram, as long as the string is without any tension the magnet stays close to the reed switch due to spring pressure keeping the reed closed.

The situation keeps the PNP switched OFF which in turn keeps our LED circuit switched OFF.

The moment string is pulled > the magnet pulls away > the reed disconnects > the PNP switches ON > our LED circuit gets activated, and starts performing the proposed actions....our LED circuit remains activated for so long as the fish is not pulled of the hook or the string looses tension.


Very cool idea. I might use that for my reset function. I got the thing to work. The base of the Q1 Detector was sent to high (Vcc) and it started working.

Blinking with no motion and fast blink (Almost like an always on but still pulsed to the speed of the opti wheel. Works!) but there wasn't any way to reset without physical grounding (Light off). once ground was removed, blinking began without motion.

Maybe a transistor to switch from reset ground of Pin 4 to the Base of Q1. Once Q1 senses motion, it trips a 3904 (?) from low to high activating the circuit then a push button momentary switch could "reset the transistor back to low until signal received again.

What do you think?

I like your idea with the magnet but again, trying to keep it simple for manufacturing. More parts, more money, then higher price on the shelf, less buyers.

I'll see what I can do though. Good work on that reed switch. I'll work on that.

I get it! Instead of a reed switch, why not use the catch/release lever to act as a switch itself. Both parts are made of metal.

I can insulate the latch from the body and once the cord releases the lever, it would make contact with the catch stop and whalla! Contact! I'll send you a pic of what I mean... One final question...

Currently, I am using 4 off-the-shelf AAA batteries to achieve 6.3vDC. However, I was wanting to reduce the package size to achieve the same or close to voltage. How long do you thing 2 coil cells like a CR2032 or similar last?

I have 2 LC-16340 3vDC @ 1000mAh batteries like the CR123A but rechargeable, but I didn't want to over power the current on the board and fry everything.

If I use the 16340's, I could add a simple charging circuit to the system and make them rechargeable. But again, I don't want to fry the board. Thoughts?

Also, I am planning on using an ultra-bright high power led for the circuit (Not sure of specs yet). Would the current values of the rest of the circuit be ok for that power? BTW, the 555 I used was a cn rated for 18v max @ 600mA.


Fine-Tweaking the Circuit

As long as the supply voltage is within 15V, current is immaterial, you can use any AH battery that suits your costing... no issues, higher current (AH) would mean greater back up time without recharging and vice versa.

As for the resetting issue of the 555 IC, the IC would cleanly stop flashing if it's pin#4 is kept aloof of any residual voltage (above 3v). I think the PNP 3906 might not be switching off completely or may be is faulty. Once Q1 switches off, Q2, Q3 should also completely switch off cutting of pin#4 of 555 from the supply completely, and grounding it via R3.

The main thing to watch out is the voltage at the collector of the PNP 3906, it should be zero voltage when the detector is not detecting anything.

I saw one more issue in our circuit, to be be more safe the detector collector should be connected with a resistor (470 ohms will be OK) so that Q2 base does not get affected. Hey brother,

The Fishing YOYO Design Finalized

Sorry I didn't get back with you. But here's an update...

The final fishing yo yo stop motion switch circuit works well enough to suite my needs. Thank you SOOO much for your help.

So this is where we are at... Tuesday, 1 Oct, I am filing for a utility patent. It takes 8-12 weeks for us to be awarded the final patent. I have a buyer lined up waiting for the patent to go through. Once the process if finalized and the sale is complete, we all get paid.

Nice working with you, Swags. You the man. Hope to work with you again in the near future.

Best Regards and God Bless you, Brother!

Mike Gimlin

Senior Design Engineer

Tyendaga Research Center

Cincinnati, Ohio 45140, USA



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