How does it know I throw Gutterballs?

December 4, 2007 8:34 PM

How does the bowling alley computer know how many pins you knocked down?

I feel like this question should be Googleable, but I couldn't find it anywhere. How does the bowling alley computer know how many pins you knocked down? This question was prompted by one afternoon's bowling, when one of my pins slid a few inches to one side, but didn't fall down. Some of my friends figured there were sensors under each pin that could tell how the weight was distributed when the pin was upright, but that doesn't really make sense to me. It seems like the pins are counted before the arm thing swoops the pins away.


Surely there aren't little men in there counting the pins, as much as we would like to imagine such a thing. So how does it work?

posted by sweetkid to sports, hobbies, & recreation (9 comments total)

There's a laser involved. Sometimes, during Cosmic Bowling, you can see it. If you look in between a pair of lanes, you'll probably see what looks like a coffee can on a little support - that's the sensor for that pair.
posted by deadmessenger at 8:38 PM on December 4, 2007

The original ones from the 1960's used a triangular clamp thing to pick up all the standing pins, so that a scraper could pull all the ones that were down out of the way. The triangular guy had separate clamps for each of the ten holes, and a switch on each that detected whether it closed all the way (indicating that there was no pin) or stopped part way (because it was holding a pin).

The pin layout display didn't get updated until the triangular thing picked the pins up.
posted by Steven C. Den Beste at 8:48 PM on December 4, 2007

This is me! I've spent 5 years working in a bowling alley.

Two common strategies involve physical contacts and optical sensors. A lot of systems use CCD sensors: basically a camera. There are various positions for their location, but what deadmessenger refers to is where I understand they're most common. I've also heard of them being overhead.

I worked in a center that used physical contacts. (For what it's worth, the machines were brand new when I got there: Brunswick GS-X pinsetters.) The machine comes down on top of the pins, and there's a lever at the top of each pin station that presses against the pin. You don't really notice that step, because, while it's down, it'll pick the pins up and sweep the deck of deadwood.

Optical sensors are generally regarded as faster, but the contact switches are considered more accurate. (We run cosmic bowling a lot, hence the importance of contact switches.)

What deadmessenger is referring to sound a lot like the infrared ball detect sensor. (A persistent cause of problems! They were in a position likely to get hit by a ball, which would throw them out of alignment, which causes all sorts of quirky behavior!) It shoots an IR beam in front of the pin deck, and sets the whole thing in motion when the beam gets crossed.
posted by fogster at 8:48 PM on December 4, 2007 [7 favorites has favorites]

http://www.essortment.com/hobbies/bowlingpinsette_ttfu.htm

Goggle is awesome. :)
posted by Brockles at 8:49 PM on December 4, 2007 [1 favorite has favorites]

This link is really useful, and spot-on with what we used. The third slide is most apropos.

And boy does it bring back memories!
posted by fogster at 8:52 PM on December 4, 2007

Oh, thanks for the links! "Pinsetter" seems to be the word I missed when Googling. I tried "bowling computer machine" or somesuch.
posted by sweetkid at 9:00 PM on December 4, 2007

This question was prompted by one afternoon's bowling, when one of my pins slid a few inches to one side, but didn't fall down.

As an aside, this can give bowling alley staff major headaches. If it moves too much, it's known as an "out of range," where the machine can't detect it. (Often it'll come down, hit the pin, and automatically go into an error mode. Other times it manifests as erratic scoring.) League regulations don't allow pins to be reset anywhere but where they ended up, so we have to manually intervene in the process.

Super off-topic, but I love reminiscing: it's generally caused by the center not keeping up on lane maintenance and letting the oil, applied to the front of the lane, get carried down to the back and not get wiped down.
posted by fogster at 9:01 PM on December 4, 2007

Fogster, the sliding pin gave me a major headache as well, because if it had fallen properly I would have had a strike. I didn't know it caused problems for staff as well. Very interesting.
posted by sweetkid at 9:05 PM on December 4, 2007

At the bowling alley I attend, I see lots of laser-esque red beams criss crossing back and forth and going from bottom to top. I assume they first check for the presence of a pin in each primary position (if the light doesn't get through, then there's a pin there), then does extra checks with the criss cross beams to ensure it's not just a fallen over pin blocking a vertical beam.

Anyway, that's how I'd do it if I were designing the system too.
posted by wackybrit at 9:40 AM on December 5, 2007