Hi there -
The title is a little misleading, the 4017 is not chasing my LEDS around the workshop. I wish it was THAT exciting.
So, I have an arduino clocking my 4017. It works to chase my jumbo LEDS (I'm using a ULN2803 to increase current to LEDs).
What I would like to do, is have a second arduino pin turn the LEDS on or off whenever I desire, while the 4017 cycles through the row of LEDs independently. I *thought* I could take the common emitter from the ULN2803 and tie that to a second transistor. Unfortunately, if the 2803's emitter is detached from ground the LEDS are still faintly visible.
I now realize I need to have a switch between 5v+ and my LEDs. Any suggestions for a good positive rail switcher? At first I thought to use a reed relay, but that will probably need replacing and slower than some other non electro-magnetic options. Would a P channel MOSFET be a good idea? It's the best thing I could find lounging around the interwebs.
/// As always, thank you for reading and checking up
The title is a little misleading, the 4017 is not chasing my LEDS around the workshop. I wish it was THAT exciting.
So, I have an arduino clocking my 4017. It works to chase my jumbo LEDS (I'm using a ULN2803 to increase current to LEDs).
What I would like to do, is have a second arduino pin turn the LEDS on or off whenever I desire, while the 4017 cycles through the row of LEDs independently. I *thought* I could take the common emitter from the ULN2803 and tie that to a second transistor. Unfortunately, if the 2803's emitter is detached from ground the LEDS are still faintly visible.
I now realize I need to have a switch between 5v+ and my LEDs. Any suggestions for a good positive rail switcher? At first I thought to use a reed relay, but that will probably need replacing and slower than some other non electro-magnetic options. Would a P channel MOSFET be a good idea? It's the best thing I could find lounging around the interwebs.
/// As always, thank you for reading and checking up