This is the Vernier Photogate, a new take on the traditional photogate. By emitting a beam of infrared light from one upright to the other, the Photogate can detect when an object passes between the upright gates, breaking the beam. Not only can this Photogate detect objects moving through the interior of itself but also outside by means of a "laser gate". Simply close a mechanical shutter to block the internal IR gate and shine a laser pen (not included) into the laser gate hole found on the thinner gate arm.
Additionally, the Vernier Photogate can be daisy chained so up to four photogates can be connected to a single channel, connecting the last one directly to the interface.
Vernier Software and Technology has been a leader in data collection and analysis for educators world-wide. They were amongst the first companies to design and promote the use of computers, sensors, and data collection in K-12 classroom laboratory experiments.
Note: Due to manufacturer’s restrictions, we can only ship these to the USA. Sorry world!
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Got it working with python running on a Raspberry Pi using proto board connectors. Gate seems very sensitive (triggers with a small wire) between the gates and still quite sensitive (triggers with a fast pencil flick) using a laser and the laser hole. I'll be trying to increase that laser sensitivity. Very happy!
Dimensions? Gate width is one thing, but height would be very useful too. None of the documents seem to include this little detail.
Can this photogate be used as bubble detection sensor? The flow rate of the tubing is 20 L/min, to detect bubble inside chemical liquid that flows through the transparent teflon tube.
As said, better uses thing like theses http://www.digikey.ca/product-detail/en/EE-SX3070/OR716-ND/368609 a 4$ each or even less if you look more than 5sec like a did. All you need after that is a couple of resistor and an Arduino,
It is great that that part is 1/10 the price, but it is no substitute. You need a separate emitter & detector. These photo gates are big enough to pass your hand through. Or a variety of cars and buggies and balls used in physics classrooms. And you can use a remote laser pointer and make the gate wide enough for an elephant to walk through.
Man, this would make it a whole lot easier to count all of my elephants...
It is great that SparkFun is making these available, but the Vernier stuff is really expensive and relies on proprietary software and an expensive interface device. What is really needed is for hackers to take these things apart and develop ways to use Arduino and a serial reads so that teachers in normal classrooms can expose their students to this technology.
The Vernier stuff is great if you work in a district that has a huge budget for technology. But in any normal school district, a lucky science teacher has about 6 bucks per kid and that doesn't go very far.
Yes, their stuff is expensive, but it is fairly durable. Kids are not kind to hardware and equipment.
Vernier publishes a How-to-make-your-own photo gate circuit: http://www.vernier.com/engineering/stem/sensors/photogate/
Other build-your-owns here: http://www.vernier.com/engineering/stem/#subject-sensors
What is really needed is some kind of hobbyist oriented equivalent of USB. The beauty of vernier is the plug and play compatibility. We need a standard way for a device to say "I am a sensor, I output the temperature and humidity". We need to get devices talking to each other. If something can be networked, it never really gets obsolete. There's always a part for it to play in a larger system. USB is great for keyboards and mice and all the other stuff USB is used for. But we need something open. Something cheap to implement. Something that anyone can make a device for without buying a VID. Something with a bus topology instead of a point to point with hubs. Preferably something all-digital. Something with decent range. Think of the possibilities if hobbyists agreed on a standard protocol that projects should speak. Then there would be a system like vernier, but with hundreds of modules available!
At least some of the Vernier sensors come with the information needed to read them directly, and Vernier does sell some breadboarding adapters:
http://www.vernier.com/products/accessories/bb-btd/
http://www.vernier.com/products/accessories/bb-bta/
OK, and I see that links to "Arduino and Vernier Sensors" were added since I made my original comment above.