Playing around with shift registers & led displays
I recently got a bunch of M74HC595 shift registers and some random 1 digit led displays from ebay (love you cheap chinese shops!), and now it’s time to try them out!
The shift registers are pretty simple to use; I just connected it to my atmega8 and borrowed some example code from this page: http://bildr.org/2011/02/74hc595/. Having previously been doing some UART and I2C stuff, I was a bit surprised that the example doesn’t care about specific frequency for the clock by adding delays or something. But no matter, it runs fine as it is with my MCU running at 8Mhz.
I didn’t try chaining up more than 1 shift register at this time, but looks like it should be easy as well.
The shift register then connects to all the pins on the led display, which then connects to ground through a hefty 2.2k resistor. For proper usage with higher current, I suppose using transistors would be appropriate.
Let’s see if wordpress can handle an animated gif:
led display gif
Here’s the setup on a breadboard. The middle chip is actually an eeprom chip, but that’s a story for another day…
And finally a shot of my workbench.
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