Answers.Body: <p>I compared the SoundTrap ST4300 clock to a camera system with a very precise RTC. The camera shutter sound could be heard in the acoustic recordings so I compared the time stamp of the images to the time stamp in the acoustic recording. I found that the drift was about <strong>41.5 seconds per day</strong>! This was in the kelp forests off San Diego, CA where water temperatures was on average 22 deg C in July 2018.</p>
  <p>See Figure S2 in the supplementary material of this paper: <a href="https://tos.org/oceanography/article/an-optical-imaging-system-for-capturing-images-in-low-light-aquatic-habitats-using-only-ambient-light" rel="noreferrer">https://tos.org/oceanography/article/an-optical-imaging-system-for-capturing-images-in-low-light-aquatic-habitats-using-only-ambient-light</a></p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2022-10-11T23:27:58.047Z
Answers.LastActivityDate: 2022-10-11T23:27:58.047Z
Answers.UserDisplayName: Camille Pagniello
Answers.Body: <p>I expect that like every RTC (real time clock) also the RTC of the soundtrap drifts: a good crystal (20 ppm) may drift up to 10 minutes per year if kept constant at 25 °C.</p>
  <p>If the temperature changes the drift increases quadratically in temperature difference from 25 °C (0.04 ppm/°C^2 is typical).</p>
  <p>More details can be found in <a href="https://www.edn.com/rtc-design-part-1-real-time-clocks-still-matter-in-automation-iot-applications/" rel="nofollow noreferrer">here</a> and <a href="https://www.edn.com/rtc-design-part-2-temperature-compensation-is-critical/" rel="nofollow noreferrer">here</a>.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2022-10-07T19:23:11.687Z
Answers.LastActivityDate: 2022-10-08T07:18:14.960Z
Answers.LastEditDate: 2022-10-08T07:18:14.960Z
Answers.UserDisplayName: WMXZ
Answers.Body: <p>We have observed up to a 15-20 offset in time after 5 month deployments with ST600s. The manufacturer is testing a fix currently to solve this issue, so within a few months, I would expect a firmware update to improve the clock accuracy.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2023-04-20T16:48:18.930Z
Answers.Text: 15-20 seconds or minutes?
Answers.UserDisplayName: WMXZ
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2023-04-24T15:44:38.303Z
Answers.Text: Sorry, 15-20 minutes. This was observed when using Periodic Recordings checked, Record 4 hours every 4 hours. This equates to continuous recordings, but limits each file to be 4 hours in duration. I am not sure if this scheduling affected our observations though.
Answers.UserDisplayName: Timothy Rowell - NOAA Federal
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2023-04-20T13:59:21.143Z
Answers.LastActivityDate: 2023-04-20T13:59:21.143Z
Answers.UserDisplayName: Timothy Rowell - NOAA Federal
Answers.Body: <p>Our group recently did a four-month deployment of SoundTraps in the northeastern Gulf of Mexico at depths ranging from ~100 to ~450 m. For the few instruments that were still recording when we recovered them (two ST500s and three ST600s), I was able to measure the exact clock offset and thus estimate their clock drifts (based on a linear drift assumption).</p>
  <p>All the units were running slow, with drifts of 5.2 an 5.6 s/day for the ST500s and 7.7, 7.6 and 7.7 s/day for the ST600s. When we got back to the lab, I ran a deck test at room temperature on one of the ST500 and recorded a drift of ~1 s/day. Unfortunately, we don't have in-situ temperature measurements but it would be interesting to determine whether these really high drifts are consistent with temperature. Also, it's interesting that the ST600s seem to be experiencing a higher drift that the 500s, which are the older model.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2022-10-15T21:15:14.480Z
Answers.Text: Ludo, you can find the in-situ temperature measurements in each of the log files.  It represents the temperature inside the unit, not the water temperature, but they should be pretty close to each other.
Answers.UserDisplayName: Melissa 
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2022-10-22T16:17:17.790Z
Answers.Text: We recently tested the drift of the ST600s in our lab at room temperature and also found drifts of about 7-8s/day, for all three devices tested.
Answers.UserDisplayName: DeniseR
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2022-10-08T12:59:11.743Z
Answers.LastActivityDate: 2022-10-08T12:59:11.743Z
Answers.UserDisplayName: Ludo Tenorio
Body: <p>Clock drift can lead to a desynchronization between clocks over time, and apparently, this clock drift can vary according to the environment/temperature according to this <a href="https://en.wikipedia.org/wiki/Clock_drift" rel="noreferrer">Wikipedia article</a>.</p>
  <p>Has anyone recorded variation in clock drift in Soundtraps deployed in different environments (temperatures and/or depths)?</p>
  
Tags: <soundtrap>
Title: Does the Soundtrap clock drift vary in different environments (temperature)?
ThreadText: # Does the Soundtrap clock drift vary in different environments (temperature)?
  
  (Asked by: username_0 on 2022-10-07)
  
  Clock drift can lead to a desynchronization between clocks over time, and apparently, this clock drift can vary according to the environment/temperature according to this [Wikipedia article](https://en.wikipedia.org/wiki/Clock_drift).
  
  Has anyone recorded variation in clock drift in Soundtraps deployed in different environments (temperatures and/or depths)?
  
  **Tags:** soundtrap
  
  
  ---
  
  ## 4 answers
  
  ### Answer by username_4 on 2022-10-08. Score: 6 | Accepted answer
  
  Our group recently did a four-month deployment of SoundTraps in the northeastern Gulf of Mexico at depths ranging from ~100 to ~450 m. For the few instruments that were still recording when we recovered them (two ST500s and three ST600s), I was able to measure the exact clock offset and thus estimate their clock drifts (based on a linear drift assumption).
  
  All the units were running slow, with drifts of 5.2 an 5.6 s/day for the ST500s and 7.7, 7.6 and 7.7 s/day for the ST600s. When we got back to the lab, I ran a deck test at room temperature on one of the ST500 and recorded a drift of ~1 s/day. Unfortunately, we don't have in-situ temperature measurements but it would be interesting to determine whether these really high drifts are consistent with temperature. Also, it's interesting that the ST600s seem to be experiencing a higher drift that the 500s, which are the older model.
  
  > **Comments:**
  > **username_5**: Ludo, you can find the in-situ temperature measurements in each of the log files.  It represents the temperature inside the unit, not the water temperature, but they should be pretty close to each other.  
  > **username_6**: We recently tested the drift of the ST600s in our lab at room temperature and also found drifts of about 7-8s/day, for all three devices tested.  
  
  ---
  
  ### Answer by username_1 on 2022-10-11. Score: 7
  
  I compared the SoundTrap ST4300 clock to a camera system with a very precise RTC. The camera shutter sound could be heard in the acoustic recordings so I compared the time stamp of the images to the time stamp in the acoustic recording. I found that the drift was about **41.5 seconds per day**! This was in the kelp forests off San Diego, CA where water temperatures was on average 22 deg C in July 2018.
  
  See Figure S2 in the supplementary material of this paper: <https://tos.org/oceanography/article/an-optical-imaging-system-for-capturing-images-in-low-light-aquatic-habitats-using-only-ambient-light>
  
  
  ---
  
  ### Answer by username_2 on 2022-10-07. Score: 4
  
  I expect that like every RTC (real time clock) also the RTC of the soundtrap drifts: a good crystal (20 ppm) may drift up to 10 minutes per year if kept constant at 25 °C.
  
  If the temperature changes the drift increases quadratically in temperature difference from 25 °C (0.04 ppm/°C^2 is typical).
  
  More details can be found in [here](https://www.edn.com/rtc-design-part-1-real-time-clocks-still-matter-in-automation-iot-applications/) and [here](https://www.edn.com/rtc-design-part-2-temperature-compensation-is-critical/).
  
  
  ---
  
  ### Answer by username_3 on 2023-04-20. Score: 1
  
  We have observed up to a 15-20 offset in time after 5 month deployments with ST600s. The manufacturer is testing a fix currently to solve this issue, so within a few months, I would expect a firmware update to improve the clock accuracy.
  
  > **Comments:**
  > **username_2**: 15-20 seconds or minutes?  
  > **username_3**: Sorry, 15-20 minutes. This was observed when using Periodic Recordings checked, Record 4 hours every 4 hours. This equates to continuous recordings, but limits each file to be 4 hours in duration. I am not sure if this scheduling affected our observations though.  
  
  ---
  
  