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Replace Bump Switch With Laser Equivalent

Thread starter #1
I have a machine that throws a tennis ball for my dog which is fine and works ok. The problem is that there is a sensor it uses to detect (simple diagram of a similar sensor here)when there is a ball ready to be thrown and when it gets dirty/wet it fails, usually after a couple of days, so it cannot detect a ball anymore. I'd like to replace it with a laser sensor or infra red switch and install it in such a way where dirt/water cannot get to it. I'm not terribly happy about the distance it throws the ball, about 20 feet, i'd prefer at leat 3 times that, so If it means rebuilding the whole thing and using a raspberry pi, so be it.

Just wondering if anybody knows of a good sensor I could take a look at that might do the job?

Thanks
 

gophert

Well-Known Member
Most Helpful Member
#2
I have a machine that throws a tennis ball for my dog which is fine and works ok. The problem is that there is a sensor it uses to detect (simple diagram of a similar sensor here)when there is a ball ready to be thrown and when it gets dirty/wet it fails, usually after a couple of days, so it cannot detect a ball anymore. I'd like to replace it with a laser sensor or infra red switch and install it in such a way where dirt/water cannot get to it. I'm not terribly happy about the distance it throws the ball, about 20 feet, i'd prefer at leat 3 times that, so If it means rebuilding the whole thing and using a raspberry pi, so be it.

Just wondering if anybody knows of a good sensor I could take a look at that might do the job?

Thanks
The answer to your question really depends on how much you want to learn about optical sensors and whether you want to drill down to the LED emitter and detector vs staying with purchased modules.

Where are you with electronics, designing & building circuit boards and wiring them up? I'm asking because ambient light often interferes with these sensors so it is not always straight forward with light.
 

dknguyen

Well-Known Member
Most Helpful Member
#3
If getting dirty makes it fail, I doubt light will be any better. Replace your contact switch with a sealed one or put it behind a membrane.

There are lots of IR proximity sensors prepackaged so you don't have to learn too much about them that you can put behind IR transparent plastic to seal from the elements, but still wonn't solve the dirty problem. Go with a mechanical switch sealed behind a membrane.

https://www.digikey.ca/products/en/sensors-transducers/optical-sensors-reflective-analog-output/546?FV=ffe00222,a80090,a80091,a80093,a80094,a8000f,a80096,a80098,a80099,a8009a,a8009b,a8009c,a8009d,a8009e,a8009f,a80010,a800a0,a800a2,a800a3,a800a4,a800a5,a800a6,a800a7,a800a8,a800a9,a80011,a800aa,a800ab,a800ad,a800ae,a800af,a800b0,a800b2,a800b8,a800cb,a80015,a800db,a800e1,a80111,a8012b,a8012c,a801d6,a801ed,a801f2,a80040,ac0002,1f140000&quantity=0&ColumnSort=0&page=1&k=ir+proximity+sensor&pageSize=500&pkeyword=ir+proximity+sensor

Raspberry Pi seems like overkill unless your dog wants for it to run Linux.

Photos of the launcher please so we know whether you're talking about an enclosed mortar setup or a more open catapult setup. Enclosed setups where you can mount an optical sensor inside the tube perpendicular to the length facing downwards should resolve ambient light effects and dirt. I imagine it's more open though so the dog can use it more easily.
 
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