I am studying digital electronics and I need to build a low-resolution camera unit which can transmit the captured frame over an RS232 comm channel. I will use a CMOS camera chip and a low cost microcontroller (ATMega or PIC) because of limited student budget.
Can you tell me if you can see any design tricks/pitfall on this project that I need to be aware of?
Where can I order a low-res CMOS camera chip in Australia?
Be aware that there are two basic types of camera chip - those with analogue output - ie video, and those with a digital output. If you build something that can 'read' video signals, then you can accept input from just about any video source. Digital camera chips tend to be much more complex and you really need to understand the datasheet. If you are unsure about this kind of thing, go for a CMUcam or AVRcam instead.
If you can find a local distributor for eg Ovonics, you can probably get free chip samples - they are so cheap these days that the distributors only want to sell you thousands. The bare chips are not particularly easy to work with - you will need to be confident with surface mount. By the time you have the skills and equipment you need, you will have spent far more than simply buying the modules.
Note that you will also need to add a lens assembly to the basic chip.
On balance, unless you really want to get into this low level stuff, I'd buy camera modules.
Hi Dave, I developed the AVRcam last year that fits this exact specification: CMOS image sensor mated to an Atmel mega8 microcontroller. It is capable of tracking up to 8 objects of 8 different user-defined colors at 30 frames/sec. It can also spit out a complete color image over a serial port. Check out:
for more details. There is also a forums section there that discusses what people are doing with the system, and what issues arise with such as system.
Feel free to post any questions you have over at that forum (or here, though I check this less frequently). Embedded image processing is certainly a fascinating topic (especially when you're trying to do it on an 8-bit micro), and it will provide a fun and exciting challenge to you.
An optical mouse may be usable for some rudimentary vision tasks, but I have no idea how it would actually work for capturing full-color images that could then be processed. The 88 x 144 is due to the fact that the OV6620 provides a 176 x 144 output format, and then I am decimating the data in each row so there is less to process.