Home security system based on Mega2560 and Mini (or Uno)

Hey everyone! Im sketching out the details of a security system, based around an Arduino Mega2560 and either a mini or Uno, depending if number of pins is a limitation.

But what Im trying to do is along the lines of this: https://howtomechatronics.com/projects/arduino-security-alarm-system-project/

But rather than have the ultrasonic sensor directly on it, id like to have it set up remotely with an ov7670 camera, and controlled through an uno or mini, then communicate to the mega using either a bluetooth sensor or esp8266 wifi sensor, again depending on pin limitations (and effectiveness of one over the other, potentially).

I dont yet have the materials to get started, as this is a commission job from a friend, but it is still part of the learning curve for me so Im starting the thread sooner than later (as I do have some of the parts I need).

But iill update here shortly, and if anyone has any advice to offer in advance thatd be much appreciated! Thanks

But rather than have the ultrasonic sensor directly on it, id like to have it set up remotely with an ov7670 camera, and controlled through an uno or mini, then communicate to the mega using either a bluetooth sensor or esp8266 wifi sensor, again depending on pin limitations (and effectiveness of one over the other, potentially).

Do I understand that correctly, you want to replace the ultrasonic sensor by camera? Does that mean you think that an Arduino is able to detect motion on a camera picture? it doesn't. It doesn't have enough memory to keep a complete picture in RAM (so it cannot compare multiple pictures to detect changes) and it needs several seconds to read out one picture from the camera. Forget that setup.

If you want to do a motion detection by camera, use a system like the Raspberry Pi, which has the memory and computing resources needed to do such a job.

Hmm, i thought a fifo chip was to help with that, but i must have been mistaken. I know without a fifo the arduinos cant, but i thought that was meant to remedy that. But if thats true ill certainly revise my approach and try that, but ill have to look more into that if i was mistaken. Thanks!

Hmm, i thought a fifo chip was to help with that, but i must have been mistaken.

A FIFO is used if some device is delivering data to fast for the recipient to handle. The data is fed into the FIFO and the recipient get it out in the same order as it was entered but at the speed it is able to handle. I guess you see that this doesn't help anything in your case.