• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

which option when flashing 160 led rapidly with using Shift Register

Not open for further replies.


New Member

ı want to flashing 160 led. ı will use pic + shift register + 160 led and pc. detail information can be seen on image.

firstly ı have 20 kb data. this data will be transfered to the pic and pic will be stored data to the program memory. then every 20 ms pic send 160 bit data to the shift register. after 20 ms pic send data to shift register that all led must be turn off with a 20 ms. so that first 20 ms some led will be turned on and second 20 ms all led will be turned off. so first mini cycle will be finised. second mini cycle will be started and 160 bit data sended again and specific leds will be flashing.

second option's difference is the where stored data. the data will be stored to the SD card or eeprom ICs. then pic read data from these memory card and stored to the data memory not program memory.

which option can ı use? or is there any another option to flashing 160 led every 40 ms? What is your opinion??

thanks a lot for your response...



To drive that many led's, I would use a driver chip like the MAX7219. It will drive 64 led's per chip in an 8x8 array. You would send the data to the chips and to flash the display, send the commands for the chip to enter and exit "shutdown" mode.



New Member
now ı want to use relay instead of led. but firstly it is too hard to use relay. so that all steps imaginable as use relay after at the end of the run with led.
thanks for the chip advice
can you comment system with use relay?

PS.....ı worked with 2 relay in 40 ms with 1. option which ı explained in my first message . there is no problem .


New Member
this project same as floating writing.
so this data consist of every led's bit which turn on or off ...
ı send data from pc to the pic with the help of c ++ program about 20 kb.
which pic can ı use? Now ı am good at 16F877A microprocessor.

Gayan Soyza

Active Member
RS 232 with max 232 chip...
we can say moving display or scrolling display..
Now only you are telling its a signboard.Its a challenge project.You need to work hard with these specially the timings.How do I time share for various events etc....

*multiplex display
*external inputs (SW)

877A is ideal.All you need is to work hard.Have you worked on a signboard before?
Last edited:


New Member
ı havent worked yet on a signboard.
firstly how can ı solve this problem? or which problem exist on this system?
is it possible to work this system with my first option?
do you have any advise? because my first trying with 2 relay receive data from shift register in a 20 ms time so it is not original system like my first option but it is similar.
when ı try this system with data of 20 kb and use 20 shift register
will be 160 led worked at the same time ?
Not open for further replies.

EE World Online Articles