Camera motion with two degrees of freedom using ESP8266, two stepper motors, Canon ELPH330HS, and CHDK (Canon Hack Development Kit).
CHDK controls the camera focus and exposure, then waits for the remote trigger (a 100 mSec pulse on the USB power line) (https://chdk.fandom.com/wiki/CHDK)
The ESP8266 solves the trig problem "SOHCAHTOA": given the Target Distance ("Opposite Side"), either increment the Camera Distance ("Adjacent Side") and calculate the Angle (atan(Opposite/Adjacent)), or increment the Angle and calculate the Camera Distance (Opposite/tan(Angle)).
The first case, Constant Linear, is what you see when you look out the window of a car: distance objects slowly approach, rapidly pass, then slowly receed.
In the second case, Constant Angular, distant objects rapidly approach, slowly pass, then rapidly receed. The samples here use Constant Angular.
When the camera has moved to position, the ESP8266 pulses the USB line to trigger the shot.
Camera horizontal motion using Actobotics "Channel Slider Kit A" (https://www.servocity.com/channel-slider-kit-a/) with a 48" channel, and a NEMA-17 stepper motor (https://www.adafruit.com/product/324).
Panning with a 25:1 gearing and a NEMA-17 stepper motor:
Horizontal resolution is 0.38 mm/step (0.015 inches/step) with 42" of travel
Angular resolution is 0.072 degrees/step
The entire process takes about 5 minutes for a 50 frame sequence, or about 6 seconds per frame.
The ESP8266 will automatically connect to the last used access point based on configuration saved in flash memory.
If this is the first time connecting (or the access point is unavailable), this program will create a soft access point with SSID: tracker and Password: carbondioxide.
Connect with a WiFi client and browse to http://tracker.local to access the program.
To configure the ESP8266 to use an existing access point, browse to http://tracker.local/config, and enter the SSID and PW. The STA IP is the assigned address on the network:
The ESP8266 will automatically connect to that network on reboot.
Load the script chdk/track.lua on the camera; switch to ALT mode; press shutter to start. The viewfinder will display *** STARTED ***:
On the ESP8266 web page http://tracker.local:
- Current Location: enter the location of the camera (measured to the motor end of the camera slider), and the current camera angle. Press Set.
- Automatic Tracking: enter the distance from the camera slider to the target, and the number of frames. Press Begin to move the camera to the beginning position (camera should still be centered on target). Press Start.
When it's done, you will have a set of images on the camera that can be converted into a stabilized GIF using scripts/createGIF.sh:
