More LED payout lights.

[browne92]

Some time ago, I had offered to do an LED payout circuit for CarlW. I was so confident in my engineering skills that I built the thing before breadboarding it. Foolish samurai. I couldn't get it to work properly, then other projects pushed it aside. I left him hanging for so long, he used his mastery of the Arduino and took matters into his own hands. Apologies to CarlW.

After putting away the latest project, I found myself inspired by a clean work table and the work that corrupt_rev had done on his circuit. So I broke out my breadboard and went at it again. It differs from corrupt_rev's circuit in that instead of flashing one LED at a time, it lights them sequentially until all are lit, then turns them off. I call it an LED Stepper, if you have a better name for it, I'd like to hear it. Behold:



I'm using 4 of the possible 7 outputs. When it receives the trigger (button push in the video, leaf switch on the pachinko), it cycles through the LED's and then resets. You can see that it will restart the sequence if the button is still pushed when the first sequence ends. You can also see the effect of changing the clock speed.

The circuit consists of a 555 timer to generate the clock pulses, a 74LS273 octal flip flop to drive the lights, a transistor to invert the reset signal (which is where I got in trouble on my first try), and a few resistors. The finished circuit will be a bit more complex... the 273 wants a regulated power supply and I'm not running any driver transistors, which is bad engineering, especially if you want to put more than one LED on each output.

The 273 has 8 outputs, so it will run up to 7 LED's, the 8th output is needed for the reset signal. It would be easy to add more 273 chips to run even more LED's in the sequence.

I'm going to draw up a schematic and post it here and on my web site. Since I try to save my weekend time for the shop and stay away from the computer, it won't be done till next week some time. I'd like to see us have a collection of these types of circuits for anyone who wants to use them. I was going to strip down the breadboard, but I'm leaving it for now in case someone has a variation on this circuit they'd like to see.

Comments and opinions welcome.