operating 8 15V relays with pic 16f627

[farhanauu]

Hi I want to operate 8 relays with the help of input stream that is generated by a 8 pixel Bitmap image.
Is there any possibility to do it, Kindly help me in this regard as I am new to micro controller programming and also suggest me some related study material.

Thanks in advance

 

[FvM]

An integrated driver like ULN2803 would be fine to control 15V relays from 5V logic, or single transistors with base series resistors and flyback diodes. You'll find pretty much relay driver examples in Edaboard discussions.

 

[farhanauu]

thanks dear, yeah i searched out a lot about this project. i tried to connect uln2803 in proteus, i connect 8 pins of PORTB to 0-7B uln2803 but i give 0V at all 0-7C of uln2803, also i dont know how to write bit stream to eeprom connected to controller, i tried to use i2c protocol but code dont work.


will you be so kind to post a link for me with code and circuit diagram, so i can understand how to use as i am new to controller programming,
i tried to find it all night but could not find it.

 

[nagkiller]

Post full project...

 

[jayanth.devarayanadurga]

I think ULN2803 only sinks current. One end of relay coil should be connected to +12V (if 12V relay) and other end to ULC2803 C pins.

 

[farhanauu]

I want to take 8 bit bmp file as input and generate bit stream with bmp file,(which i can do using matlab) i dont know if there is any function in PIC for doing this.
then i want to write generated bit stream to an eeprom using (i2c protocol), now i want micro controller to take bit stream as input and according to input operated 8 relays connected to the 8 output pins of micro controller.
I have attached input bitmap image.
Kindly help

 

[pinout]

Just a comment on the relay outputs, don't forget that relays are relatively slow activating and releasing, so OK for things like water drop control imaging, but not anything visual where you pulsing lights/ Leds fast. If filament lights you have additional thermal lags. Just some comments as I'm not sure what you are driving with the relays.
Replacing the relays and driver chip with a more powerful driver will get round the relay lag if that's an issue.

 

[farhanauu]

bitmat image generates pattern for microcontroller output pins,
for example steam generated by R is,
1 1 1 0 0 0 0
1 0 0 1 0 0 0
1 0 0 1 0 0 0
1 1 1 1 0 0 0
1 0 0 0 1 0 0
1 0 0 0 0 1 0
1 0 0 0 0 0 1

now 1 means port pin high and 0 means port pin low, if high operates relay,

 

[jayanth.devarayanadurga]

Store your pattern in an array as 7 bytes. The MSB will be 0 for each row of pattern. Take each row of array and then extract LSB to MSB-1 bits one at a time and then operate relays accordingly.

 

[farhanauu]

hmm but what to do if my stream size is more...
i have more patterns say 1000 7 bit patterns?

 

[jayanth.devarayanadurga]

Store it in external eeprom.

 

[farhanauu]

hmm... thanks do u have code + schematic how to store in external eeprom??

 

[jayanth.devarayanadurga]

It depends upon Compiler. I use mikroC Compiler.

 

[farhanauu]

i also use mikroc pro for pic, can u give me that?

 

[jayanth.devarayanadurga]

It has a example of using eeprom. Look at it.