The picture attached is the wiring for my project, i am trying to blink each led in sequence(one by one) when user press a button
i'm concerned that my wiring or concept is wrong, so give me any suggestion and confirmation.
The LED are 12 VDC, and i hooked up the positive end of LED to 12 V and negative end to the output of uln2003A. it is right?
(the led comes with resistors)
I'm starting to see why people hate that fritz thing.
Very useful comment cj.
It is not as much Fritzing!, but the users who are allowed (by Fritzing!) to just draw some lines and ask "what do you think about my schematics".
Hi george221.
Your breadboard has 2 "power rails"; one on top and one on the bottom.
You have used the bottom one for the 5 volts (coming from your Arduino), and jumpered it to the top one.
But you aren't using the top one.
So why do you not use that top one for the 12 volts from the batteries, which makes wiring a lot easier.
Now this doodle is already a mess if you want to check out the power supply.
Always try to prevent to cross wires, and if you must, cross them at a 90 degrees angle.
You've got multiple wire colors available.
Use those to show different kinds of signals (like red for power and black for GND).
That will make your Fritzing! sketches a lot easier to read for everyone.
Are you aware that the ULN2003 inverts the signals ?
So if you put 5 volts to the input, it will output 0 volts and vice versa.
You connected pin 10, !MR (not master reset, which is active low) directly to GND.
That means master reset is always on.
So whatever you do is reset before you will see any result.
Can't be right.
You also have pin 13, !OE fixed to GND.
So that one is always active, and all outputs should be immediate.
I'm not sure that is the correct way to do things (i have no practice with this device yet).
MAS3:
You also have pin 13, !OE fixed to GND.
So that one is always active, and all outputs should be immediate.
I'm not sure that is the correct way to do things (i have no practice with this device yet).
The output enable (active low, pin 13) should be grounded, otherwise you get no outputs at any time.. The outputs are only updated when the latch (pin 12) is pulled from low to high.
The problem is holding Master Reset (active) low.
Since the LEDs are connected to the 12V supply, they will be turned on when the ULN2003 receives a HIGH input.
Only one problem to fix - but it does make sense to use the upper "red" rail for the 12V for the LEDs instead of 5V for nothing.
