Millisecond Forums » Millisecond Forums » Inquisit 7 » absolute timestamps, elapsedTime, and synchronization with Empatica

absolute timestamps, elapsedTime, and synchronization with Empatica

Kosinski_Lille — Fri, 19 Jun 2026 14:41:37 GMT

Hi,
I am currently programming a fear conditioning task in Inquisit 7 and I would like to synchronize stimulus presentation with electrodermal activity recorded using an Empatica EmbracePlus device.
My goal is to obtain, for each stimulus onset, an absolute timestamp that can be converted or matched to Empatica timestamps, which are expressed as UNIX timestamps in UTC, typically in microseconds.
I understand that script.currentTime returns the current time only with second-level precision, while script.elapsedTime provides millisecond precision from the start of the script. However, I would like to know what is the cleanest and most accurate method to obtain an absolute stimulus onset time with millisecond precision.
More specifically:
1. Is there a built-in property in Inquisit 7 that provides the absolute time of a stimulus onset with millisecond precision?
2. Should I use properties such as stimulusOnsetTime or stimulusOnsetTimestamp for this purpose?
3. Are these values based on the actual onset of the stimulus on screen, or on the scheduled onset in the trial?
4. Is it possible to export an absolute UTC timestamp directly from Inquisit?
5. If not, what would be the recommended procedure to reconstruct an absolute UNIX timestamp from script.elapsedTimeand the script start time?
At the moment, my intended workflow is to export the Inquisit event script.currentTime, convert the stimulus onset times to UNIX timestamps in microseconds, and then align them with the Empatica EDA data in post-processing.
Could you please confirm the most reliable way to do this in Inquisit 7?
Thank you very much for your help.
Best regards,
Thierry

RE: absolute timestamps, elapsedTime, and synchronization with Empatica

Kosinski_Lille — Fri, 19 Jun 2026 14:41:37 GMT

+x[quote]

[b]Dave - 6/19/2026[/b]
+x[quote]

[b]Kosinski_Lille - 6/19/2026[/b]
Hi,
I am currently programming a fear conditioning task in Inquisit 7 and I would like to synchronize stimulus presentation with electrodermal activity recorded using an Empatica EmbracePlus device.
My goal is to obtain, for each stimulus onset, an absolute timestamp that can be converted or matched to Empatica timestamps, which are expressed as UNIX timestamps in UTC, typically in microseconds.
I understand that script.currentTime returns the current time only with second-level precision, while script.elapsedTime provides millisecond precision from the start of the script. However, I would like to know what is the cleanest and most accurate method to obtain an absolute stimulus onset time with millisecond precision.
More specifically:
1. Is there a built-in property in Inquisit 7 that provides the absolute time of a stimulus onset with millisecond precision?
2. Should I use properties such as stimulusOnsetTime or stimulusOnsetTimestamp for this purpose?
3. Are these values based on the actual onset of the stimulus on screen, or on the scheduled onset in the trial?
4. Is it possible to export an absolute UTC timestamp directly from Inquisit?
5. If not, what would be the recommended procedure to reconstruct an absolute UNIX timestamp from script.elapsedTimeand the script start time?
At the moment, my intended workflow is to export the Inquisit event script.currentTime, convert the stimulus onset times to UNIX timestamps in microseconds, and then align them with the Empatica EDA data in post-processing.
Could you please confirm the most reliable way to do this in Inquisit 7?
Thank you very much for your help.
Best regards,
Thierry
[/quote]

I think what you want is the stimulusOnsetTime property, which should give you the precise onset date and time in UTC, including milliseconds.

You can then apply Date.parse() to the value to get the UNIX timestamp.

In a nutshell:
[code]<values>
/ onsetTimeUTC = null
/ unixTimestamp = null
</values>

<text myText>
/ items = ("Press the space bar to continue")
/ fontStyle = ("Arial", 2.08%, false, false, false, false, 5, 1)
</text>

<trial myTrial>
/ onTrialEnd = {
    values.onsetTimeUTC = text.myText.stimulusOnsetTime;
    values.unixTimestamp = Date.parse(text.myText.stimulusOnsetTime);
}
/ preTrialPause = 500
/ stimulusTimes = [1=myText]
/ validResponse = (" ")
</trial>

<block myBlock>
/ trials = [1-10=myTrial]
</block>

<expt myExpt>
/ blocks = [1=myBlock]
</expt>

<data>
/ columns = (date, time, subject, group, session, blockNum, blockCode, trialNum, trialCode, response, latency, correct,
    values.onsetTimeUTC, values.unixTimestamp)
</data>[/code]

Example output:
[code]date    time    subject    group    session    blockNum    blockCode    trialNum    trialCode    response    latency    correct    onsetTimeUTC    unixTimestamp
2026-06-19    14:16:27    1    1    1    1    myBlock    1    myTrial    57    719    0    2026-06-19T12:16:28.649Z    1781871388649
2026-06-19    14:16:27    1    1    1    1    myBlock    2    myTrial    57    297    0    2026-06-19T12:16:29.891Z    1781871389891
2026-06-19    14:16:27    1    1    1    1    myBlock    3    myTrial    57    1860    0    2026-06-19T12:16:30.715Z    1781871390715
2026-06-19    14:16:27    1    1    1    1    myBlock    4    myTrial    57    859    0    2026-06-19T12:16:33.087Z    1781871393087
2026-06-19    14:16:27    1    1    1    1    myBlock    5    myTrial    57    297    0    2026-06-19T12:16:34.453Z    1781871394453
2026-06-19    14:16:27    1    1    1    1    myBlock    6    myTrial    57    312    0    2026-06-19T12:16:35.257Z    1781871395257
2026-06-19    14:16:27    1    1    1    1    myBlock    7    myTrial    57    312    0    2026-06-19T12:16:36.081Z    1781871396081
2026-06-19    14:16:27    1    1    1    1    myBlock    8    myTrial    57    297    0    2026-06-19T12:16:36.904Z    1781871396904
2026-06-19    14:16:27    1    1    1    1    myBlock    9    myTrial    57    344    0    2026-06-19T12:16:37.729Z    1781871397729
2026-06-19    14:16:27    1    1    1    1    myBlock    10    myTrial    57    656    0    2026-06-19T12:16:38.573Z    1781871398573[/code]
[/quote]

Perfect ! thank you !

RE: absolute timestamps, elapsedTime, and synchronization with Empatica

Dave — Fri, 19 Jun 2026 12:17:56 GMT

+x[quote]

[b]Kosinski_Lille - 6/19/2026[/b]
Hi,
I am currently programming a fear conditioning task in Inquisit 7 and I would like to synchronize stimulus presentation with electrodermal activity recorded using an Empatica EmbracePlus device.
My goal is to obtain, for each stimulus onset, an absolute timestamp that can be converted or matched to Empatica timestamps, which are expressed as UNIX timestamps in UTC, typically in microseconds.
I understand that script.currentTime returns the current time only with second-level precision, while script.elapsedTime provides millisecond precision from the start of the script. However, I would like to know what is the cleanest and most accurate method to obtain an absolute stimulus onset time with millisecond precision.
More specifically:
1. Is there a built-in property in Inquisit 7 that provides the absolute time of a stimulus onset with millisecond precision?
2. Should I use properties such as stimulusOnsetTime or stimulusOnsetTimestamp for this purpose?
3. Are these values based on the actual onset of the stimulus on screen, or on the scheduled onset in the trial?
4. Is it possible to export an absolute UTC timestamp directly from Inquisit?
5. If not, what would be the recommended procedure to reconstruct an absolute UNIX timestamp from script.elapsedTimeand the script start time?
At the moment, my intended workflow is to export the Inquisit event script.currentTime, convert the stimulus onset times to UNIX timestamps in microseconds, and then align them with the Empatica EDA data in post-processing.
Could you please confirm the most reliable way to do this in Inquisit 7?
Thank you very much for your help.
Best regards,
Thierry
[/quote]

I think what you want is the stimulusOnsetTime property, which should give you the precise onset date and time in UTC, including milliseconds.

You can then apply Date.parse() to the value to get the UNIX timestamp.

In a nutshell:
[code]<values>
/ onsetTimeUTC = null
/ unixTimestamp = null
</values>

<text myText>
/ items = ("Press the space bar to continue")
/ fontStyle = ("Arial", 2.08%, false, false, false, false, 5, 1)
</text>

<trial myTrial>
/ onTrialEnd = {
    values.onsetTimeUTC = text.myText.stimulusOnsetTime;
    values.unixTimestamp = Date.parse(text.myText.stimulusOnsetTime);
}
/ preTrialPause = 500
/ stimulusTimes = [1=myText]
/ validResponse = (" ")
</trial>

<block myBlock>
/ trials = [1-10=myTrial]
</block>

<expt myExpt>
/ blocks = [1=myBlock]
</expt>

<data>
/ columns = (date, time, subject, group, session, blockNum, blockCode, trialNum, trialCode, response, latency, correct,
    values.onsetTimeUTC, values.unixTimestamp)
</data>[/code]

Example output:
[code]date    time    subject    group    session    blockNum    blockCode    trialNum    trialCode    response    latency    correct    onsetTimeUTC    unixTimestamp
2026-06-19    14:16:27    1    1    1    1    myBlock    1    myTrial    57    719    0    2026-06-19T12:16:28.649Z    1781871388649
2026-06-19    14:16:27    1    1    1    1    myBlock    2    myTrial    57    297    0    2026-06-19T12:16:29.891Z    1781871389891
2026-06-19    14:16:27    1    1    1    1    myBlock    3    myTrial    57    1860    0    2026-06-19T12:16:30.715Z    1781871390715
2026-06-19    14:16:27    1    1    1    1    myBlock    4    myTrial    57    859    0    2026-06-19T12:16:33.087Z    1781871393087
2026-06-19    14:16:27    1    1    1    1    myBlock    5    myTrial    57    297    0    2026-06-19T12:16:34.453Z    1781871394453
2026-06-19    14:16:27    1    1    1    1    myBlock    6    myTrial    57    312    0    2026-06-19T12:16:35.257Z    1781871395257
2026-06-19    14:16:27    1    1    1    1    myBlock    7    myTrial    57    312    0    2026-06-19T12:16:36.081Z    1781871396081
2026-06-19    14:16:27    1    1    1    1    myBlock    8    myTrial    57    297    0    2026-06-19T12:16:36.904Z    1781871396904
2026-06-19    14:16:27    1    1    1    1    myBlock    9    myTrial    57    344    0    2026-06-19T12:16:37.729Z    1781871397729
2026-06-19    14:16:27    1    1    1    1    myBlock    10    myTrial    57    656    0    2026-06-19T12:16:38.573Z    1781871398573[/code]