Camera troubles
I’m setting up a calibration platform for particle sensors, and I need a camera to capture the data from the Dylos sensor, because it only outputs data over serial once per minute, and I need once per second. So I need to capture an image of the number output on the display, process it and extract the data. Unfortunately, I don’t have any webcams lying around the house, and I’m not about to go spend $20 for one when I have another camera here. It’s a small camera, probably the same as in your laptop and webcams. (I was going to use it as a remote security webcam, but then I found out it’s much harder to interface a camera with a microcontroller than I thought.) So I hooked it up to an easyCAP I have with a patch cable, and tried to interface it with Python on a Windows laptop, which became very difficult. Eventually, I was able to get it working with this tip. The steps I had to take to get it working were:
- get a power supply for the camera, I found from my handy-dandy power supply that 'positive' polarity is required, and 4.5V is the minimum (on my PSU) that would power the camera. A 9.6V PSU was making the camera get very toasty, not good for long term use. The manual says use 5-12V
- in device manager, right click your laptop webcam under 'Imaging Devices', and choose disable
- install DVDriver
- install cv2 for python (I had to use version 2.4.10 for windows to get KNearest working)
- run the cv2 demo
- profit
The cd that came with easyCAP is here if anyone needs it.
With linux, this is easier because you can call mplayer with subprocess.