4
Photogate.
When two Go Direct Photogates are daisy-chained together, you can connect
either of the photogates to your device via USB or Bluetooth
®
wireless
connection. Once the first gate is connected, the second gate becomes the
“Remote Gate” of the connected photogate. The Remote Gate or the Time of
Flight Pad are set up using the connected sensor’s Remote-Gate sensor channels.
Remote Gate – Object Velocity
This sensor channel reports Object Velocity values for the Remote Gate when
two Go Direct Photogates are daisy-chained together. See Object Velocity for
details on the reported data.
Remote Gate – Object Acceleration
This sensor channel reports Object Acceleration values for the Remote Gate
when two Go Direct Photogates are daisy-chained together. See Object
Acceleration (multiple flags) for details on the reported data.
Gate 1/Remote Gate – Timing
This sensor channel reports the time between successive blocked events for
Gate 1 of the connected gate and Gate 1 of the daisy-chained Remote Gate or
Time of Flight Pad. This pulse time does not depend on the order the gates are
blocked and is reported at the time the second gate is blocked.
Laser Gate/Remote Gate – Timing
This sensor channel reports the time between successive blocked events between
the Laser Gate of the connected gate and Gate 1 of the daisy-chained Remote
Gate or Time of Flight Pad. This pulse time does not depend on the order the
gates are blocked and is reported at the time the second gate is blocked.
Selecting this sensor channel activates the Laser Gate on the Go Direct
Photogate. This channel cannot be used with other sensor channels except for
Laser Gate – Gate State. See Laser Gate – Gate State for instructions on setting
up a Laser Gate.
Tips for using Remote-Gate Sensor Channels
l
The default data-collection mode for Remote-Gate sensor channels is Time-
based. No values are recorded for these sensor channels when using
Photogate Timing modes.
l
Objects with multiple flags will report multiple timing values. The average
of the multiple timing measurements can be used to represent the average
time for the object to pass between the two gates.
l
You cannot use the Laser Gate on a daisy-chained Remote Gate. To collect
data using two Go Direct Photogates both in Laser Gate mode, connect both
sensors directly to your device.
l
You cannot get the gate-state data from a daisy-chained Remote Gate. To
collect data using two Go Direct Photogates both in Gate-State modes,
connect both sensors directly to your device.
Experiments Using Go Direct Photogate
Go Direct Photogates can be used for several experiments in the books
Physics
state channels can be used with Photogate Timing modes for additional data-
collection options including replication of traditional photogate data-collection
experiments. The channels can also be used on their own in time-based mode if
you want to require students to do hand calculations using photogate data.
Gate 1 – Gate State
This sensor channel reports changes in gate state and associated times for
Gate 1.
Gate 2 – Gate State
This sensor channel reports changes in gate state and associated times for
Gate 2.
Laser Gate – Gate State
This sensor channel reports the gate state changes and the associated times for
the Laser Gate. Selecting this channel activates the Laser Gate on the Go Direct
Photogate. This channel cannot be used with other sensor channels except Laser
Gate/Remote Gate – Timing.
To use the Laser Gate, a visible-light pen laser (not included) must be pointed at
the Laser Gate photodiode (located below the
icon) on the Go Direct
Photogate. The Laser Gate LED indicator will be solid blue when the laser is
not aligned or when the gate is blocked. The Laser Gate LED indicator will be
off when the Laser Gate sensor channel is selected, the laser is aligned, and the
gate is unblocked.
Note:
It may be easier to adjust the laser first for the desired path, and then
place the gate so that it aligns with the laser beam (Laser Gate LED indicator
turns off).
Tips for using Gate-State Sensor Channels
l
When gate-state channels are the only channels selected, the default data-
collection mode is set to Photogate Timing.
l
Gate-state values for blocking events are reported as 1.
l
Gate-state values for unblocking events are reported as 0.
l
Use gate-state sensor channels for experiments involving linear or angular
motion timing (position, velocity, and acceleration measurements), pendulum
timing, and object timing (time between gates).
l
The times associated with blocking events are used in the pulse-time
calculations for Object Velocity and Object Acceleration channels.
l
The Projectile Launcher Photogate Timing option cannot be used with
Go Direct Photogates as the sensor channels are not configured the same as
on a Projectile Launcher.
l
When using a Vernier Ultra Pulley Attachment (not included), you must use
the Gate 2 – Gate State sensor channel as the pulley does not block Gate 1.
Remote-Gate Sensor Channels
The Remote Gate sensor channels are used when a Go Direct Photogate is
daisy-chained to a second Go Direct Photogate or to a Time of Flight Pad.
Using these channels require accessory cables not included with the Go Direct