Survey3 HDMI PWM Trigger + Exposure Strobe Cable
Use this cable to send a PWM pulse to the Survey3 camera to perform various functions. See the diagram below for the HDMI pins that are connected and the required PWM pulse to send depending on the function you want to perform.
To trigger the shutter (take a photo) send the camera a 2000us pulse. Use the 1000us as a neutral, do not do anything level.
You can also send the camera a 1500us pulse width to have the camera enter USB Media Transfer mode. If the camera is connected to a computer using the USB/POWER/FPV port, when in transfer mode the camera's SD memory card will then become mounted to the computer and you can access it just like the SD card was plugged into the memory card reader on your computer. This is very useful if using a companion computer such as on a drone, in that you can then extract the images from the camera and onto the computer's memory. Then you can do anything you want, such as process the photos or store them onto an external memory stick or SSD to easily take the photos off your drone.
Every time the Survey3 camera captures an image it sends out a strobe / flash pulse that can be logged by an external recorder. A common recorder example is a vehicle computer such as a UAS/drone flight controller. You can also use a small computer like a Raspberry Pi or a microcontroller like a Arduino. The strobe pulse is a high (3V3) when active, otherwise the pin is low (ground). If you log the exposure pulse against time and location you can edit the image location data in post processing to be more accurate. This is known as PPK, or Post Process Kinematics.
In our testing the average delay between trigger and exposure pulses is around 100ms (0.1s). As in example of how much movement can exist with a 0.1s delay, think about the camera attached to a drone moving at 15m/s. In that 0.1s time the camera will move 1.5m (5ft), which is a large difference. Using the exposure pulse GNSS location data should improve your orthomosaic results.
Product Specifications:
| Length | 20cm (8 inches) | |
| Weight | 2.1g | |
| HDMI Connection | HDMI Micro Connector | |
| 3-Wire - Dupont Female - White Wire | PWM Pulse Signal INPUT | pin 2 |
| 3-Wire - Dupont Female - Red Wire | Exposure Pulse Signal OUTPUT | pin 15 |
| 3-Wire - Dupont Female - Black Wire | Ground | pin 4 |
| 2-Wire - Dupont Female - Red Wire | 5V Power OUTPUT | pin 19 |
| 2-Wire - Dupont Female - Black Wire | Ground | pin 13 |
