Photogates are a staple of every physics lab, used to teach students fundamental concepts about measuring time intervals and calculating speed and acceleration from their measurements. Physics teachers prefer photogates over traditional stopwatches due to their increased accuracy.

Photogates are a timing device that measure times of the changes in state of an infrared beam that is blocked by a flag of known length, as well as the times the beam is unblocked. Using the flag length, and the blocked time, students can calculate speed. The smaller the flag length, the more “instantaneous” the measurement becomes. Using a “Picket Fence” (a card with multiple flags), students can calculate acceleration.

Photogates can also measure the rotation of a pulley with wide enough spokes that act as “flags” to block the photogate’s infrared beam.

Typical Applications

  • Determining g, acceleration due to gravity
  • Speed and Acceleration
  • Projectile Motion
  • Atwood’s Machine
  • Collisions
  • Impulse and Momentum
  • Conservation of Momentum
  • Kinetic Energy
  • Simple Pendulum
  • Centripetal Acceleration
Photogate Collisions
Studying collisions. Shown is a Smart Gate with a Photogate Head daisy chained to it. Both are attached to a dynamics track using photogate brackets and the PAScars are equipped with Cart Picket Fences.
Photogate Collisions
Using a Smart Gate and a Super Pulley to measure the acceleration on the PAScar.

The Smart Gate

PASCO’s newest smart gate, the Wireless Smart Gate has the same features as the PASPORT Smart Gate but does not require an interface. Instead, it connects directly to your computers, Chromebooks, tablets or smartphones either through Bluetooth 4 or via USB.

Smart Gates are an advancement in the design of the traditional photogate. Both the PASPORT Smart Gate and the Wireless Smart Gate can be configured for all the traditional uses of a standard photogate, and with their new features, experiments that a standard photogate cannot do.

Smart Gates contain two photogates spaced 1.5 cm apart which gives them a more accurate measurement of speed over any traditional photogate. The rise and fall times of Smart Gate measurements are faster than any other photogate, which results in more accurate timing. Smart Gates also include an auxiliary port for daisy chaining an extra Photogate Head or a Time of Flight Accessory. Use the built in photogate tape guide to use our Mylar Photogate Tape for measuring the speed and acceleration of fast moving objects that are too large to pass through the Smart Gates.

Smart Gates also include a laser switch which enables a simple laser pointer to be used as the beam. This is useful for measuring timing of objects that are very large, or when you need a very long beam spacing.

Smart Gates have the same mounting footprint as our traditional photogate head, and are compatible with all of PASCO’s photogate compatible apparatus.

Wireless and PASPORT Smart Gate Features

  • Two Photogates Spaced 1.5 cm
  • Photogate Tape Guide
  • Laser Switch
  • Auxiliary Port
  • Includes Mounting Rod

Smart Gate Compatibility

The PASPORT Smart Gate is directly compatible with PASPORT interfaces (except the Xplorer GLX and SPARK Science Learning System). The Wireless Smart Gate is compatible with devices that natively support Bluetooth 4 or that use our USB Bluetooth Adapter. See wireless compatibility details. It can also connect directly to devices with a standard USB port.

Wireless Smart Gate

The Wireless Smart Gate has all the features of the wired Smart Gate plus the added flexibility of wireless connection to your data collection system.

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Smart Gate

Photogate that can be connected to any PASPORT interface, has auxiliary port to daisy chain gates, double beams for accurate speed measurement, and a special photogate tape slot.

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Projectile Launcher Smart Gate System

Study projectile motion and measure speeds accurately with the system containing the mini launcher and Smart gate.

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The Photogate Head

Originally designed as part of PASCO’s original line of ScienceWorkshop sensors, the Photogate Heads are compatible with the 550 and 850 Universal Interfaces, legacy ScienceWorkshop interfaces, and require the Digital Adapter to connect to PASPORT interfaces such as the AirLink. See interface comparisons. The Photogate head can also be daisy chained to a Smart Gate.

Photogate Head

Monitors the motion of objects passing through its gate, counting events as the object breaks the infrared beam.

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Accessory Photogate

Includes a Photogate Head and Photogate Stand for flexible experiment design.

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Photogates and Fences Dynamics System

When used with the computer for data recording, displaying and analysis, this photogate/pulley timing system can provide a wide range of time, speed and velocity measurements.

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Standalone Options

If you don’t plan to use PASCO software or would just prefer an independent system, the Digital Photogate Timer Systems and Smart Timer Systems are available.

The Digital Timer System is a complete system that is simple and reliable with high resolution. It has simple onboard memory to record two times.

The Smart Timer System is a standalone timer that can control one or two of our photogate heads. It is available separately (with included picket fences) or as a complete system.

The Smart Timer has simple setup buttons for all the most common uses of a photogate including picket fences, pendulums, collisions, dual gates pulleys and more.

Digital Photogate Timer System

Includes a Digital Photogate Timer and an Accessory Photogate.

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Photogate Timer

PASCO digital photogate timers are used in thousands of physics labs throughout the world.

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Smart Timer Photogate System

This system includes two Photogates and a PASCO Smart Timer for measuring time, speed, acceleration, and count.

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Smart Timer

A versatile cost-effective, portable way for making accurate time, speed, acceleration, and count measurements.

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Smart Gate and Photogate Accessories

Time-of-Flight Accessory

Use with a Photogate to capture time of flight data. Timing starts when object passes through photogate and stops when object impacts this landing pad. For use with PASPORT and ScienceWorkshop Interfaces.

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Photogate Mounting Bracket

This bracket mounts one or two Photogate Heads or a Smart Gate on any PASCO Projectile Launcher.

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Photogate Pendulum Set

Set of four pendula (brass, plastic, wood, and aluminum) that are ideal for PASCO’s Photogate Head and Photogate Accessory in timing experiments.

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Picket Fence

A rectangular piece of clear plastic with evenly spaced opaque bands.

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Super Pulley with Clamp

Upgrade force tables and inclined planes with this pulley and clamp.

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Super Pulley

Low-friction design produces excellent results. The precision spacing of the 10 spokes makes it ideal for photogate monitoring.

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Photogate Stand

Designed to hold an Accessory Photogate (ME-9204B).

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Photogate Brackets (2 Pack) -- IDS

The Photogate Bracket is designed to attach Photogate Head to PAStrack and Curved PAStrack.

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Atwood’s Machine

Two Super Pulleys mounted on a long rod produce a classic, low-friction introduction to Newton’s Second Law.

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Apparatus Commonly Used With Smart Gates / Photogate Heads

Basic PAScar PAStrack System

The Basic PAScar/PAStrack system is made up of plastic carts and a plastic track without the accessories package.

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Projectile Launcher

Launch plastic spheres up to 5.0 m high with repeatable results.

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Centripetal Force Apparatus

Show students the relationships between centripetal force, velocity, radius and mass.

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Rotating Platform

The stable base and precision bearings is one major component of the Complete Rotational System (ME-8950A).

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Additional Resources

If you have additional questions regarding our equipment or software, contact PASCO Technical Support. We're here to help.