[temba]

Hi everyone,

To avoid too many misunderstandings please understand I have no background in processor programming apart from basic Arduino usage as a hobby. Programming in C++, perl, python and php have been my areas of expertise.

My pilot project is to create a device that has a webcam, wifi and microphone connected to it. The audio and video streams will happen via wifi to a pc. Yes, it sounds like a surveillance unit which it pretty much is. I cannot buy a standard surveillance unit as it needs re-programming to make it function as needed.

The unit will be powered by battery and solar power (if possible, should be) so lowest power usage is a want.

I have been looking at the Cortex processors and with my basic understanding, the A5 seems as a good choice to cater for low price and sufficient power to drive the audio, video and the streaming of these via the wifi.

There is a possibility that in the future, a SIM card unit may be added to send SMSes but this is not a vital requirement at present.

As professionals, would you recommend this processor or perhaps another one?

Thanks for your help.

Regards
M-T

This post has been edited by temba: 06 June 2011 - 09:43 AM

[Exophase]

ARM doesn't actually sell processors to end-users as packaged silicon, but instead sells their cores as IP to be integrated with other peripherals on third party chips. So the question you should be asking isn't what ARM processor to buy, but which microcontroller or system on chip/applications processor to buy.

At this moment I'm not aware of any silicon containing Cortex-A5, and it's possible it won't end up publicly available in an apps processor at all (it could be delegated to being embedded in fixed function modules like basebands). I'm going to make the assumption that you aren't planning on having hundreds of thousands of these devices made. If this is the case it's essential that you buy something that is cheap and available in low volume, preferably with development kids cheaply available too. In fact, if you're only making one of these for yourself you may be best off sticking with nothing but development kits.

I recommend something like AM/DM37xx from TI (for instance AM3715 or AM3705 could be sufficient). I recommend this over OMAP35xx because of the added camera image processor. You can buy a Beagleboard-xM and third party camera module (https://www.leopardi..._xM_Camera.html). Another option is to connect a standard webcam (possibly with microphone as well) via USB, but you might have problems with space (I assume there's a reason you're not just doing this with a laptop). You can wire a WiFi module over MMC, SPI, I2C, etc, but I recommend doing it over USB to save yourself the software headache. You can get microphone over the stereo-in, it's available through the audio capabilities of the power supply chip.

Beagleboard makes their schematics open, so it's a great starting point even if you do want to make your own PCB.