need help choosing sensors for a hockey shooting target

[SAINT1000]

i am building a hockey shooting trainer in my basement. it will have 5 targets and 5 corresponding light. when the pc turns on a light next to a target you must shoot at that target. i built a false wall that is 8 feet wide by 7 feet high. on this wall i painted a regulation size hockey goal. in the 1,3,4,5,6 hole position on the goall i cut 10" round circles. on the back side of each round hole is a 12"x12" square target mounted to the wall with a gate t hinge allowing the target to swing back. a bunge cord mounted to either side of the 12x12 square target holds the target to the back of the wall acting like a spring , so when the target is hit it will move back a little then return to flush with the back of the hole. the target does not move back far enough to allow the pack to pass through the hole. i need 5 sensor that will pick up a target being hit but not giving false positives when a target is not hit. the sensors will be wired to a digital i/o usb board connected to my pc.
i tried using a shock sensor but it is to sensitive and reads a target hit when no target was hit. i was thinking of using alarm magnetic sensors but worry about the same problem. if the magnetic switch is mounted to the back of the wall to the bottom of the hole, if the wall is struck by a puck on the front side of the wall will the impact be enought to trigger the switch even though the target wasnt hit? any other ideas?

 

[ChrisP58]

Do the targets move an 1/8th of an inch or more? If so, you should be able to use a momentary push button switch. You will want to make sure to limit the target travel so that the switch doesn't get broken though.

Another idea would be to use a photocell to see when the target moves enough to break the beam.

 

[Roff]

If you were using reed switches as your magnetic sensors, they are vibration sensitive. You might want to consider a Hall Effect sensor. if you do, be sure you get one whose output is digital.
Here is an example. There are others available.

 

[SAINT1000]

i was thinking of using a switch but couldnt come up with a good way to mount it. i was also thinking of using a strip ofcontact tape on the front of the 12x12 target where it contacts the back of the wall and another one on the wall its self so when the target was closed the 2 pieces of cantact tape would be touching then when a target was hit, it would open the circuit. any thoughts on this. i could just solder a wire to the contact tape.

 

[Roff]

i was thinking of using a switch but couldnt come up with a good way to mount it. i was also thinking of using a strip ofcontact tape on the front of the 12x12 target where it contacts the back of the wall and another one on the wall its self so when the target was closed the 2 pieces of cantact tape would be touching then when a target was hit, it would open the circuit. any thoughts on this. i could just solder a wire to the contact tape.

I suspect that a hard hit on the surrounding board would cause enough bounce to give you a false score. You could add a magnet to hold the target closed unless a direct hit is scored. I would also worry about dirt on the contacts.

 

[SAINT1000]

WHAT ABOUT USING A SENSOR LIKE THIS.
https://www.robotshop.com/sfe-digital-ir-line-sensor-qre1113.html
I COULD PAINT THE SIDE OF THE 3/4" 12X12 TARGET AND MOUNT THE SENSOR FACING THE SIDE OF THE TARGET ON THE BACK OF THE WALL. WHEN THE TARGET GETS HIT AND MOVE AWAY FROM THE SENOR IT WILL SEE WHITE LIGHT. ANY THOUGHTS?

 

[Roff]

WHAT ABOUT USING A SENSOR LIKE THIS.
https://www.robotshop.com/sfe-digital-ir-line-sensor-qre1113.html
I COULD PAINT THE SIDE OF THE 3/4" 12X12 TARGET AND MOUNT THE SENSOR FACING THE SIDE OF THE TARGET ON THE BACK OF THE WALL. WHEN THE TARGET GETS HIT AND MOVE AWAY FROM THE SENOR IT WILL SEE WHITE LIGHT. ANY THOUGHTS?

Might work. I would still worry about vibration, as long as the target is spring-mounted (bungee) to the board.
I still like the Hall Effect device. It has hysteresis, and with a rare earth (neodymium) magnet, you could have a pretty good range of movement required for triggering. You could buy a Hall Effect device and a rare earth magnet, and test the range without having to mount it on your board/target.

 

[SAINT1000]

i like the hall effect sensor idea but how would i mount it?

 

[Roff]

i like the hall effect sensor idea but how would i mount it?

You build a little circuit board, with the Hall Sensor and the USB interface on it. You mount this on the "wall", near the edge of the target. You glue (or screw) a rare earth magnet to the edge of the target, so that it is near the sensor, and moves away from it when a score occurs. When the magnet moves far enough away from the sensor, due to a score, the sensor output changes state briefly. You sense this with the PC.
You can empirically determine the required placement of the magnet relative to the sensor without connecting to the computer, if you want. Just make a little breadboard with the Hall sensor, a resistor, and an LED, power the circuit with a wall wart or a 9V battery, and move the magnet back and forth near the Hall sensor, observing the spacing when the LED switches on, and when it switches off.

BTW, I save magnets from the worn-out heads of my Sonicare toothbrush. There are 2 in each head, and they are powerful little buggers. Don't know if they would work for you. Just an idea.

 

[SAINT1000]

are there any pre built boards out there. i dont have the capabilities to make one.

 

[Roff]

are there any pre built boards out there. i dont have the capabilities to make one.

A common platform for breadboards is **broken link removed**. It is available from various sources.
Google "strip board layout" for ideas and tools for laying out and building breadboards.

There are other breadboard materials available.

How were you going to build your other ideas?

 

[languer]

How about a switch like this one: https://www.pololu.com/catalog/product/1403

Or a sense pad like this one: https://www.pololu.com/catalog/product/1696

 

[SAINT1000]

everything else is already done. i bought these
**broken link removed**
**broken link removed**
wrote the code in vb.net.
thw last thing i need to do is get the triggers for the targets

 

[Roff]

everything else is already done. i bought these
**broken link removed**
**broken link removed**
wrote the code in vb.net.
thw last thing i need to do is get the triggers for the targets

And that is what this entire thread has been about. What did you decide to do about the triggers?

 

[SAINT1000]

havent decided yet. here are the ones im thinking about

https://dx.com/p/hall-magnetic-sens...ign=Arduino &gclid=CKW54K21nrYCFY9DMgod5mcAJw

https://www.sparkfun.com/products/9454

https://www.sparkfun.com/products/9414

i like the idea of the hall effect switch but am concerned about a magnet being connected to the target and wether i could keep it there. a switch would also work but will it hold up. i am thinking i will end up with the line switch. with that i dont need to mount anything to the target. they are very cheap so if they dont hold up well oh well and they output a digital signal. mounted next to the side of the target, paint the side black, and hopefully all work out.

 

[Roff]

Just keep in mind that, for the line follower, black is relative to white. The sensor relies on reflection. A sensor staring off into space will see no reflection. You need something white for it to see when the target is at 'home". Perhaps you can mount a reflector on the wall, near the far edge of the target.

 

[SAINT1000]

what if i paint the ide of the target white so it see a reflection at idle then loses the reflection when its hit?

 

[Roff]

what if i paint the ide of the target white so it see a reflection at idle then loses the reflection when its hit?

That should work.