cliffclivin
Newbie level 4
Hello.
I would like to modify a timer's design I have built, but do not have electronics workbench any more sad.gif
I do not know that much about electronics, I've built a few velleman kits, made radio's as a kid. Kinda basic working knowledge.but with gaps. When I was at uni part of the computer course involved using Electronics workbench. This was mostly 4 bit binary adders, jk flop flops etc I understand how the timer circuit works, and am taking a stab at modifying its design. But without help from Uni, or electronics workbench I'm feeling stretched. I want to think this through before buying the bits and playing...
I have built a cycle timer with plans from the web. It is powered by a 555 astable, producing clock pulses of 1hz, 93% duty cycle.
Thee pulses feed into two x 4020b 12 stage binary ripple counters. The counters are connected to one side of a Dual D Type flip flop.
(Circuit Diagram)
**broken link removed**
The timer cycles between 2 pre set delays ( selectable of 2, 16, 32 to 16,384 secs (4hours32mins4secs)), with a relay energised for the first time period, and not for the second time period.
I would like to modify the timer to produce 3 set delays, but energising two relays. One relay is on during the first time period, and the other relay is on during the last time period.
Currently, the relay is energised when the timer is turned on. After the pulse from the counter resets the flip flop, the relay is off until the pulse from the second counter sets the flip flop again.
My idea is to use both sides of the flip flop - and use the 2 flip flops to cycle between the three time periods. And use a third 4020 counter.
My idea:
Counter A starts count. Relay A is on
Counter A finishes count, resets flip flop A, Relay A is off. Starting Counter B.
Counter B finishes count, Resets flip flop B, Starting Counter C, Relay B turns on.
Counter C finished count, Sets Flip Flops A and B, Relay B turns off. Relay A Turns ON, Counter A starts count.
I have drawn a diagram of how I think this would be connected. I have only included connections for the logical side of things (Path of the clock pulses) I have only shown the 2 second leg on all three 4020b counters for clarity.
**broken link removed**
Any help is much appreciated. Self education can be such a head ache!
Will this work as I expect it to? Any ideas welcome!
Cliff
I would like to modify a timer's design I have built, but do not have electronics workbench any more sad.gif
I do not know that much about electronics, I've built a few velleman kits, made radio's as a kid. Kinda basic working knowledge.but with gaps. When I was at uni part of the computer course involved using Electronics workbench. This was mostly 4 bit binary adders, jk flop flops etc I understand how the timer circuit works, and am taking a stab at modifying its design. But without help from Uni, or electronics workbench I'm feeling stretched. I want to think this through before buying the bits and playing...
I have built a cycle timer with plans from the web. It is powered by a 555 astable, producing clock pulses of 1hz, 93% duty cycle.
Thee pulses feed into two x 4020b 12 stage binary ripple counters. The counters are connected to one side of a Dual D Type flip flop.
(Circuit Diagram)
**broken link removed**
The timer cycles between 2 pre set delays ( selectable of 2, 16, 32 to 16,384 secs (4hours32mins4secs)), with a relay energised for the first time period, and not for the second time period.
I would like to modify the timer to produce 3 set delays, but energising two relays. One relay is on during the first time period, and the other relay is on during the last time period.
Currently, the relay is energised when the timer is turned on. After the pulse from the counter resets the flip flop, the relay is off until the pulse from the second counter sets the flip flop again.
My idea is to use both sides of the flip flop - and use the 2 flip flops to cycle between the three time periods. And use a third 4020 counter.
My idea:
Counter A starts count. Relay A is on
Counter A finishes count, resets flip flop A, Relay A is off. Starting Counter B.
Counter B finishes count, Resets flip flop B, Starting Counter C, Relay B turns on.
Counter C finished count, Sets Flip Flops A and B, Relay B turns off. Relay A Turns ON, Counter A starts count.
I have drawn a diagram of how I think this would be connected. I have only included connections for the logical side of things (Path of the clock pulses) I have only shown the 2 second leg on all three 4020b counters for clarity.
**broken link removed**
Any help is much appreciated. Self education can be such a head ache!
Will this work as I expect it to? Any ideas welcome!
Cliff
