Trying a bit of older tech, and wanted to make sure I had it right.
Am wanting to power a matrix of LEDs using a few 4017 decade counters, and see just how low a power consumption I can keep it, using cheap parts.
This would be used as a general wash type of light, for a small closet or camping tent.
small, lightweight, and fairly long running.
I know using a micro, be it atmel or pic would be the best, and will be doing that as well just for comparison. Use of a micro would probably be the least expensive route, and the way I've put this together, would require only minor changes.
Circuit explanation (see attached schematic):
JP5: pin1: 6V in from NiMH battery pack for powering the 4017s
pin2: 3.6V in for powering the LEDs
pin3: clock signal from 555 timer
pin4: ground or common
JP1, 3: row 1 - 7
JP2, 4: column 1 - 21
IC1, 2, 3: ULN2003 sink arrays, for the columns
IC4: rows driver, with PN2907A to power the rows
IC5, 6, 7: columns driver set
The question I have is do I have it right for strobing individual LEDs?
Clock signal would be about 200Hz, with a duty cycle of 1.5% [Will this be high enough?]
Clock signal comes in to IC5, and is cascaded through the columns. CarryOut from the last column driver goes to the clock in for the rows, advancing to the next row.
Link to the **broken link removed**.
Closer detail of **broken link removed**.
Am I missing something, like pull-up or down resistors etc?
Thanks!
Am wanting to power a matrix of LEDs using a few 4017 decade counters, and see just how low a power consumption I can keep it, using cheap parts.
This would be used as a general wash type of light, for a small closet or camping tent.
small, lightweight, and fairly long running.
I know using a micro, be it atmel or pic would be the best, and will be doing that as well just for comparison. Use of a micro would probably be the least expensive route, and the way I've put this together, would require only minor changes.
Circuit explanation (see attached schematic):
JP5: pin1: 6V in from NiMH battery pack for powering the 4017s
pin2: 3.6V in for powering the LEDs
pin3: clock signal from 555 timer
pin4: ground or common
JP1, 3: row 1 - 7
JP2, 4: column 1 - 21
IC1, 2, 3: ULN2003 sink arrays, for the columns
IC4: rows driver, with PN2907A to power the rows
IC5, 6, 7: columns driver set
The question I have is do I have it right for strobing individual LEDs?
Clock signal would be about 200Hz, with a duty cycle of 1.5% [Will this be high enough?]
Clock signal comes in to IC5, and is cascaded through the columns. CarryOut from the last column driver goes to the clock in for the rows, advancing to the next row.
Link to the **broken link removed**.
Closer detail of **broken link removed**.
Am I missing something, like pull-up or down resistors etc?
Thanks!
Last edited: