Neurotechnology Research Systems
Optogenetic Controller
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If you have a long pattern that actually consists of smaller repeated pattern, the best option is to
define a pattern consisting of just one basic unit and then use a digital input to trigger all of the
controllers at the same time. As an example, rather than repeating a 1 second pattern 3600 times in
software or a file, you could define the 1 second pattern, set the number of repetitions to 1, and
trigger all of the controllers with the same 1Hz digital input. This will prevent drift between
Controllers.
10.3
LED Flashes when changing from voltage to current mode
If an LED is connected to the controller while it is in voltage mode and the output is switched to
current mode, a brief pulse of light approximately 4ms long will occur as the current output
stabilizes at zero. The current generation circuit is designed to hold the voltage applied to the LED
just below the turn on threshold so that light can be generated as quickly as possible in response to
a start command. When the controller is in voltage mode, the current generating circuit is
disconnected from the LED. This prevents it from setting its output at this threshold value. When it
is switched to current output, there is a brief stabilizing period lasting approximately 4ms. The
easiest way to avoid this is to switch to current mode before connecting the LED to the controller or
before connecting the patch cable to the LED module.