We make a device called Triggy (
https://tinyurl.com/v79tr7zf) that can produce TTL outputs with the same precision as the synchronization between channels of any audio device. It accepts audio (or photocell, or pressure) inputs and converts each input into a precisely timed TTL output. We are the US/Canada representative for Biosemi, so Triggy was designed to address the need for trigger timing precision to match the high sampling rates the ActiveTwo system provides for auditory neuroscience applications.
Triggys TTL onset times are ultra-precise. With an analog audio source, the response time is a function of the internal propagation delay of 0.25 nanoseconds. Onset jitter and interchannel differences are thus practically unmeasurable. Offset time (the length of TTL outputs) are set by an analog RC time constant circuit, so they can vary a bit, owing to the imprecision of passive components. However, four of the eight channels can be latched together so that their output durations match perfectly, making it easier to interpret the four bits as a nibble by applying a binary mask to the TTL output byte.
I'd be happy to answer any questions about Triggy or demonstrate specific functionality either over Zoom or in an edited YouTube video. Just drop me a line offline.
Best regards,
Lloyd Smith
President
Cortech Solutions, Inc.
E-mail:
LSmith@xxxxxxxxxxxxxxxxxxxx Tel: 910-362-1143 x202
Cell: 910-431-2811
On Fri, Aug 4, 2023, 11:18 PM Abigail Noyce <
anoyce@xxxxxx> wrote:
Hi Auditory list! Do you have an EEG triggering setup that you're happy with? Can you tell me about it? We are using the BioSemi EEG system, with a custom hardware box that converts auditory channel output to TTL pulses. This has worked well enough, but the custom hardware boxes are aging and starting to fail, and are not well documented or supported. We'd like to move to an off-the-shelf solution. We've recently purchased a new product, but we haven't gotten it working reliably (not calling anyone out here!). We need to be able to record multi-bit triggers, at sub-millisecond precision. What's out there that's working for people?