Low Power Mode (LPM) allows for more energy efficient shooting, by powering on only part of the Mach II controller each time a photo is triggered. It is designed to be used for short periods of fast interval shooting, where not every photo needs to be immediately uploaded.
By way of example, a scenario where you might use LPM is at a significant mid-project event like a concrete pour. LPM will allow you to shoot at fast intervals (e.g. every 20 seconds), while connecting and uploading a photo less frequently (e.g. every 30 minutes). This means you’re able to both shoot at fast intervals, while still getting regular photos and updates on how your system is performing.
- Your photoSentinel Mach II must be fitted with a remote shutter release cable (distinct from the USB cable). This is not available on some DSLR models, including the Nikon D3400 and D3500.
- Your photoSentinel Mach II must be on firmware version 4.0 or later. If your system is on an older firmware version, contact our Support team to update.
Limitations of LPM
The primary function of LPM is to shoot and save photos on to the SD card with minimal power use, for as long as possible. To achieve this power efficiency, LPM limits some of the other normal functionality, as follows:
- The fastest frequency at which photos can be triggered is every five seconds.
- The fastest connect and upload frequency is every five minutes, though less frequent – e.g. every thirty minutes – is recommend to maximise power efficiency.
- Photos are not immediately saved to the external drive, but are transferred in bulk when the rest of the controller powers up to connect to the cellular network.
- Photos that are not uploaded (e.g. saved locally for later manual collection) will not be deleted from the SD card, which means the SD card can fill up and the system will stop taking photos. Ways of dealing with this are outlined below.
- Uploading photos is the most power-hungry activity of the Mach II system. So, if you don’t need to upload any photos during your fast shooting session, we recommend configuring the connection settings to “Don’t upload but do provide status updates” every 30 minutes, and uploading all photos at the end of the session using End of Day Uploads.
- If you do want to upload some photos during the session, we recommend not uploading any more frequently than every thirty minutes. Each time the system connects, it will upload the single latest photo, and the rest of the photos can be uploaded using End of Day Uploads.
- If you are shooting fast sessions across multiple days, then we recommend collecting the photos manually from the external drive rather than using End of Day Uploads. This will save significant power and enable you to keep shooting at fast intervals for longer. Where you are shooting multiple fast sessions, we also recommend using a 12V car battery with the External Battery Box to ensure you have enough power to capture all your photos.
Remote format of SD card might be required
The standard workflow for the Mach II is that it will not remove a photo from the SD card until it confirms the photo has been both transferred to the external drive and uploaded. If it cannot confirm both of these have occurred, it will leave the photo on the SD card as a precautionary measure to ensure it isn’t lost. Once the SD card is full, the system will cease to take photos.
When shooting in LPM, there are two ways to collect the images: End of Day Uploads or manually from the external drive. Where End of Day Uploads successfully uploads all photos, the SD card will be cleared at the end of each day. Where, however, End of Day Uploads is not used and the plan is to manually collect the images from the external drive, the SD card will not be automatically cleared and so will progressively fill up. Even where End of Day Uploads is used, the SD card may also fill up before the end of the daily session if the photo files are particularly large.
Unfortunately, when shooting in LPM, there is no way to reliably read the SD card space, so it can’t be monitored on the Status page. To ensure your SD card does not fill up completely and cause the system to stop taking photos, we recommend calculating how long it will take to fill up your SD card (based on file size and frequency of photo-taking) and setting a reminder to log into Control Hub and remotely format the SD card. The next time the system connects, it will format the SD card, freeing up the space needed to continue shooting. Unfortunately, it may format the SD card before syncing all new photos to the external drive, and so some of the most recent photos (captured since the previous connection) may be lost. This is a known limitation of LPM.
Alternatively, you can get an update on the current SD card free space by interrupting the LPM session and putting the system back into Normal Mode, with matching take and upload intervals. When it next connects in Normal Mode, the SD card space will be reported and, if needed, you can format the card before returning to the LPM session.
If you plan to use LPM without End of Day Uploads, we recommend calculating how long it will take to fill up your SD card and setting a reminder to log into Control Hub and remotely format the SD card.