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I was wondering if there were any USB powered web cams for the Raspberry pi that are specifically No-IR. I know about the camera module which plugs directly into the board, I was wondering however if there are any alternatives, usb powered so I could perhaps plug in more than one camera simultaneously. RPI has application logic, so I can use C# + Mono to code some .NET apps to use the cameras. I also anticipate eventually the RPI will have more memory allocated to subsequent models, but even if they don't some of the newer versions have 1gb of RAM, so I don't anticipate any problems. One of the most intersting things that I have learned with No-Ir cameras is that many things have IR Distance sensors (lasers) built in which you wouldn't necessarily want to have as close to your face as they frequently are. Point and case... Iphones/droids and the light sensors on the fronts of them.

So basically guys, a NO-IR camera can see wavelengths that we can't.

Also if you find any code/books which regaurdless of language discuss camera operations please post info/titles/links etc.

Edited by overwraith
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— short, practical notes that expand on your two points (USB NoIR alternatives and the build error), plus quick commands you can reuse.

"NoIR" usually means "no infrared cut filter" — i.e., the sensor will capture near‑IR as well as visible light. The official Pi NoIR modules are exactly that (NoIR = no IR filter); consumer USB webcams vary: some include an IR‑cut for natural colours, others are IR‑sensitive or have removable/switchable IR‑cut units. For USB webcams you want either a camera that explicitly lists “IR‑cut / ICR (removable)” or a UVC/industrial camera that documents IR sensitivity. (raspberrypi.com)

Practical buying tips: prefer UVC‑compliant devices (better out‑of‑box Linux support), look for hardware MJPEG/H.264 encoding if CPU on the Pi is a concern, and check the spec sheet for “IR‑cut / NoIR / night vision” or an explicit ICR mechanism — many CCTV/industrial cameras do this. If you only find consumer cams, some people remove the tiny IR filter under the lens (not recommended unless you’re comfortable disassembly). Example vendor modules show motorised IR‑cut filters for day/night use. (arducam.com)

Multi‑camera notes: use a powered USB hub and mind USB bandwidth/power limits on older Pi models; USB 2.0 buses are shared and high‑resolution streams can saturate them. Use v4l2 tools to enumerate and tune cameras (v4l2-ctl --list-devices, v4l2-ctl -d /dev/video0 --list-formats-ext). (raspberrypi.com)

About your linker error: it happens when non‑position‑independent object files are linked into a shared object. Recompile all .o files with PIC and then relink. Quick fixes:

make clean
make CFLAGS="-fPIC -O2 -g"

Or add CFLAGS += -fPIC to the Makefile before building. If you’re cross‑building for the Pi, confirm toolchain/arch match (building x86_64 objects and trying to make an ARM .so will fail). See the GCC notes on -fPIC for details. (gcc.gnu.org)

For code: on Linux the common stacks are libv4l2 / libuvc and OpenCV; for .NET on the Pi many use OpenCvSharp or EmguCV wrappers or call native libraries from Mono. Use v4l2 tools to validate cameras before wiring them into your app.

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I also got an error while compiling a library on a linux development virtual machine. If anybody knows how to get make to build correctly that could be very helpful.

devmint-virtual-machine rflechner-raspberrycam-2fa7c69d10aa # make
cc -shared -fPIC RaspberryCam.o log.o src.o src_file.o src_raw.o src_test.o src_v4l1.o src_v4l2.o  parse.o dec_jpeg.o  -lgd -o RaspberryCam.so
/usr/bin/ld: RaspberryCam.o: relocation R_X86_64_32 against `.rodata.str1.1' can not be used when making a shared object; recompile with -fPIC
RaspberryCam.o: error adding symbols: Bad value
collect2: error: ld returned 1 exit status
make: *** [RaspberryCam] Error 1
devmint-virtual-machine rflechner-raspberrycam-2fa7c69d10aa #
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