4015 with Arduino


I'm having multiple issues with this project. I know I've managed to screw it up, but I'll start with the basics. I'm making an LED stacker using an Arduino nano as a substitute for a 555. This will allow me to time the stack with sound and modulate the speed of the chaser as needed.

original sketch with 555

I set up the whole circuit in Circuit Wizard. For now, I'm focusing my attention on the two 4015s and I'll add the 4017 into the circuit once I have this functioning properly.

The first issue I'm running into is that I need to verify if I damaged my 4015s. When I set up my pin diagram to solder my perf board, I neglected to add in the grounds to the chips. So I have powered the circuit without the chips being grounded. This resulted in all the LEDs being powered. Once I realized my error, I soldered the grounds and now nothing works.

Taking some readings with my DMM, I discovered the output pin I'm using from the Arduino only rises to 1V instead of 5V, but I have a 1k resistor on the Vdd pin for the first 4015. So the chip only has 1.8V across it. This should allow the clock pin to activate so long as it's within 0-2.3V.

Each output pin is showing 0.15 V, regardless of if the input pins have been pulsed or not, which makes me think the logic gates have been ruined.

As for the Arduino code itself, all I have it right now is periodically sending pin 13 high, much like flashing an LED. I have it working on 1 second intervals for now while I troubleshoot this issue.

Best Answer

Firstly, the 1V may well be a short circuit as stated in your comments.

Secondly, why are you powering the logic with a resistor, exactly? You shouldn't do that. It'll drop more or less voltage depending on the chip's activity, potentially causing huge troubles with consistency. And the logic will probably not work properly at 1.8V.