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Slot car motion sensor
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Slot car motion sensor

by Str8run on Sun May 09, 2021 6:53 pm

Hello, I’m trying to sense motion of a 1/64 scale electric slot car so the passing of the car triggers a timer relay to activate a string of LED nano lights.
I’ve managed to activate the lights thru the timer relay. The relay has a trigger that requires 3v to trip it.
I’m using a IR break beam sensor-3mm leds part #2167. I can wire up and see the sensors working with a volt meter. I also wired in the resistor and can see 3v output, but when I wire it into the trigger it doesn’t seem to have enough current to trip the trigger.
This seems like I’m missing something here. Do I need some sort of microcontroller?
If I could just get the motion sensors to trip a relay, I could use that voltage to trigger the timer relay. Do that make a relay for that?
Any help here is greatful. Please reply in simple terms. I am not any sort of engineer or electrician. Just trying to get a simple hobby toy to trip a string of lights.

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Re: Slot car motion sensor

by adafruit_support_bill on Sun May 09, 2021 7:28 pm

You don't specify what relay circuit you are using. But relays require a substantial amount of current to activate. And the relay coil takes some time to build the magnetic field needed to actuate the relay.

So, the problem could be a matter of insufficient current or insufficient time. If you can provide some more specific details about your circuit we might be able to offer some more specific advice.

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Re: Slot car motion sensor

by Str8run on Mon May 10, 2021 9:32 pm

Thanks for replying, I agree with you that I’m not drawing enough current to activate the relay.
You had asked for more information on the relay. Now I ordered it online, I’m not sure of the manufacture but what I can tell is the part number on the bottom of the circuit board is XY-J02, the description is a 6-30v relay module switch trigger time delay circuit timer cycle adjustment.
I was thinking, if I can’t wire direct to this XY-J02 circuit directly. Can’t I just wire a different relay that is functional with the motion sensor, then feed a acceptable current supply thru the switching side of the relay to do the trick on the trigger side of the relay circuit
I feel I have two choices here. Can you suggest the best route?

Str8run
 
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Re: Slot car motion sensor

by adafruit_support_bill on Tue May 11, 2021 6:39 am

I found an instruction sheet for that relay module - although some of the triggering details are a bit vague. http://www.mantech.co.za/Datasheets/Pro ... 02-BEL.pdf

Can you post a photo showing how you have everything wired?
Also post a photo of the back of the relay board.

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Re: Slot car motion sensor

by Str8run on Wed May 12, 2021 9:36 pm

Yes, that is it. I wired it up exactly the way it is . I’m supplying it 12v from a power pack. The only mods I did was converted the out put from 12v to 3v using a couple diodes and a resister to run the lights after it triggered.
I activate the trigger with a 3v disk battery thru a switch located under the track. When the pin on the car trips the switch the trigger is complete.
The problem is the pin on the car doesn’t like the switch in it’s way.
That’s why I was hoping to use a off track sensor to trigger the relay on the timer.
You have as much information as I do. Everything in that link is correct.
Now if you had that relay, how can I incorporate the IR sensor to trigger that relay. All I need is more current
If you still want a picture, it’s more of a mock up. Not really sure how I could show you it’s wire. There’s only 2 inputs ( supply and trigger) and 1 output with the option of NO or NC. Your best bet is going off the the research you found. I will send a photo over the week end. I have to stage it up for its photo shot.
Thanks for helping, this will be really cool if you can get this working. I’m hoping for a simple fix

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Re: Slot car motion sensor

by adafruit_support_bill on Thu May 13, 2021 5:45 am

All I need is more current

Probably not. What you need is a positive going pulse to activate the relay. The BreakBeam sensor has a negative going output.

You can use an inverter circuit to fix that: These are available in chip form. Or you can roll-your-own with a transistor & a couple of resistors.
https://en.wikipedia.org/wiki/Inverter_(logic_gate)

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Re: Slot car motion sensor

by Str8run on Thu May 13, 2021 11:07 am

That sounds great, looks like you have a solution.
Now can you help me build it. Please send a parts list and a circuit drawing and I will make an attempt to build an inverter. Please include how the sensor, the inverter and the relay are joined. Try to keep it simple.

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Re: Slot car motion sensor

by adafruit_support_bill on Thu May 13, 2021 1:10 pm

Attachments
Circuit.png
Circuit.png (102.23 KiB) Viewed 228 times

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Re: Slot car motion sensor

by Str8run on Thu May 13, 2021 2:51 pm

Wow, that is great. Only 3 parts and you gave me the link to order them.
Can you do me one more favor and hook me up the same for another circuit , so I can order all the parts at once.
I need a simple circuit to produce the required 5v supply from a 12v power pack.
Thank you so much, I am amped to try this!

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Re: Slot car motion sensor

by adafruit_support_bill on Thu May 13, 2021 3:16 pm

One of these will do it: https://www.adafruit.com/product/4739

But looking closer at this spec sheet: http://www.mantech.co.za/Datasheets/Pro ... 02-BEL.pdf
it says it can handle a trigger level up to 24v. So you probably don't need the 5v.

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Re: Slot car motion sensor

by Str8run on Thu May 13, 2021 7:00 pm

Are you saying I can go ahead and plug 12v into the circuit instead of 5v and it won’t hurt the transistor or the motion sensor?

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Re: Slot car motion sensor

by adafruit_support_bill on Thu May 13, 2021 7:34 pm

The PN2222 transistor can handle up to 40v. But the break-beam is only designed for up to 5v. So you probably do still need the buck converter for the sensor at least:
https://www.adafruit.com/product/4739

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Re: Slot car motion sensor

by Str8run on Thu May 13, 2021 9:23 pm

Ok, thanks for your help. I’m filling my shopping cart. I will message you in the near future and let you know how I made out

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Re: Slot car motion sensor

by Str8run on Tue May 25, 2021 10:26 pm

Just a heads up. I ordered the parts you suggested would work. I received them and soldered them together and hooked it up to the relay. It didn’t work, I have not had time to probe it. But informing you I’m still in a jam
Any suggestions on where I may have gone wrong?

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Re: Slot car motion sensor

by adafruit_support_bill on Wed May 26, 2021 5:40 am

If you post some photos showing all your soldering and connections, we can take a look.

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Please be positive and constructive with your questions and comments.