I2C questions

Projects General Guidance
23

hmm ok. interesting. I don't know much about i2c (hints the topic title)

I bought the Arduino book "going further with sketches" it said it had a bunch of i2c stuff in there.

hopefully it will shine some light on this project for me.

I've only been doing Arduino projects for about 5 months or so.
(completely new to micro controllers and coding)

after I get that part all down then the code for what I want it to do might be tricky.

its a 8x8 pixel IR sensor. I basically need if X percent of pixels above threshold then digitalWrite.

I really don't need to see it in a 8x8 LED module.

Thanks for the help everybody. I'm sure i'll be posting something about this in the future.

24

since the device has only two options, you could make a bunch of pro-mini boards and then network them together.

the ESP8266 offers the software choice as was pointed out, and I would assume the newer ESP32 with it's 32 GPIO pins might offer up to 32 sensors if you can put 2 sensors on a 2-pin bus.......

and that is before any sort of multiplexing.....

25

LandonW:
they are on a break out board but I can only use two because of the address code...

Connect the address selector pin to an output pin, and use it as chip select.
Then you can have as many as you want on the same bus.

Multiple grid-eye sensors on one bus?
I hope you do know that I2C has wire length limitations.
Leo..

26

at most it would be 16 inches / 32 cm from sensor to Arduino

27

Wawa:
Datasheet tells me that these sensors can be set to two addresses.
1101000 when AD_select is connected to ground, and 1101001 when connected to VDD.

if I used digital pins to supply 5v to ADO on the break out board of the sensor it will be 1101001.

if I write that pin low will 0v act as gnd and make it 1101000???

28

also what is the INT option for? INT is interrupt from what I've seen.

what is its purpose?

29

LandonW:
also what is the INT option for? INT is interrupt from what I've seen.

what is its purpose?

To provide a source of interrupts to the connected microcontroller

30

but what exactly does that do? shut off the sensor or stop communication or what?

and why would the unit/sensor need interrupted?

I have a book on order to maybe help with it. I was just asking to get some more/extra info

31

but what exactly does that do?

Why don't you look at the device datasheet to find out what interrupts it can generate?

32

I'm curious about this sensor. Some applications are suggested in the data sheet, but it doesn't explain what advantages this particular sensor brings to those use cases. There are not enough pixels to form a useful infrared image. If you want to measure objects' temps, you don't need 64 answers. If you want to detect moving warm objects, a far cheaper PIR sensor will do that. Someone please let me into the secret!

33

I've done useful commercial image processing on 32x32 monochrome video images, so 8x8 is a challenge, but great fun.

34

PaulRB:
If you want to detect moving warm objects, a far cheaper PIR sensor will do that. Someone please let me into the secret!

can you post some part numbers for those sensors??

35

LandonW:
if I used digital pins to supply 5v to ADO on the break out board of the sensor it will be 1101001.

if I write that pin low will 0v act as gnd and make it 1101000???

Correct.
Set only one module e.g. HIGH, and read that one.

INT in donkey talk is basically "pick me, pick me, pick me"
Leo..

36

LandonW:
but what exactly does that do? shut off the sensor or stop communication or what?

and why would the unit/sensor need interrupted?

It's the other way around: the sensor producing an interrupt. Normally by changing the INT line from LOW to HIGH or the other way around upon certain events - check data sheet for details. Your MCU can respond to this, if you connect this line to one of your IO pins and create an interrupt for it in your sketch.

37

LandonW:
can you post some part numbers for those sensors??

I just meant the standard PIR motion sensors you can buy anywhere, like eBay.
s-l300 (7).jpg

s-l300 (7).jpg

38

Even those "standard" sensors come with part numbers and data sheets. What you believe to be "standard" may be just one of several very similarly looking devices.

39

that style isn't suitable for my project. too bulky and similar ones that are smaller wont work either.

40

wvmarle:
Even those "standard" sensors come with part numbers and data sheets. What you believe to be "standard" may be just one of several very similarly looking devices.

"Common" rather than "Standard" is the word I should have used. Or "bog-standard"

41

LandonW:
that style isn't suitable for my project. too bulky and similar ones that are smaller wont work either.

Well, if the application is a secret, there is only so much help you can get on a forum and you have to accept that you will get suggestions that are not helpful.