2 pulses from 1
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Posted by Terry Pinnell on February 28, 2005, 3:10 pm
Please log in for more thread options I'm sure there must be a smarter way to do this than my first design. I want to produce separate +ve going 12V pulses at the leading and trailing edges of a low impedance 12V input. My first draft looks too complex: - Use R/C/diode edge detector to produce OUT 1. - Also take input to half a 4013 to produce FF - Logic NOR the input with the inverted FF - Use R/C/diode edge detector to produce OUT 2 Here's the timing chart: http://www.terrypin.dial.pipex.com/Images/2From1.gif I think those crude output pulses should be adequate without further cleaning up, as they go to the respective Set and Reset inputs of a simple 4001 bistable. Of course, squared up outputs would be a bonus; I might do that anyway if I have any spare 4001 gates. For the curious, it's an add-on for my curtain controller, to open and close them either at dawn/dusk or at specific times of day. Any simpler way to achieve this please? -- Terry Pinnell Hobbyist, West Sussex, UK | ||||
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Posted by Ken Moffett on February 28, 2005, 3:51 pm
Please log in for more thread options > http://www.terrypin.dial.pipex.com/Images/2From1.gif
Terry, Someplace in the past I remember using an edge detecter circuit for the count output of a rotory encoder. I think it was from one of the "Design Ideas" in Electronic Design(?). It used an XOR gate with an RC delay on one of the two inputs. The other input was direct. The output pulse width was a function of the RC time constant. -- --- - - | | | | || || || || --- --- XOR -- --- --- -- --- __ ---+----------------| | | ___ | |------- +---|___|---+----|__| | --- --- | ---------------+--------------- Edge Detector created by Andy´s ASCII-Circuit v1.24.140803 Beta www.tech-chat.de | ||||
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Posted by Fred Bloggs on February 28, 2005, 4:27 pm
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Terry Pinnell wrote: > I'm sure there must be a smarter way to do this than my first design.
> I want to produce separate +ve going 12V pulses at the leading and > trailing edges of a low impedance 12V input. > > My first draft looks too complex: > > - Use R/C/diode edge detector to produce OUT 1. > - Also take input to half a 4013 to produce FF > - Logic NOR the input with the inverted FF > - Use R/C/diode edge detector to produce OUT 2 > > Here's the timing chart: > http://www.terrypin.dial.pipex.com/Images/2From1.gif > > I think those crude output pulses should be adequate without further > cleaning up, as they go to the respective Set and Reset inputs of a > simple 4001 bistable. Of course, squared up outputs would be a bonus; > I might do that anyway if I have any spare 4001 gates. > > For the curious, it's an add-on for my curtain controller, to open and > close them either at dawn/dusk or at specific times of day. > > Any simpler way to achieve this please? > View in a fixed-width font such as Courier. 4070_ +---------------- | | | >--+------>OUTN
| | +-/ /__/ | |
IN>---+-[R]-+--| o --+ +-| o-->OUTP
| |/ |/
[C] 40106 40106 | | --- ------------ | | | | IN ------- ----------- ------- --------- ------- | | | | OUTN | | | | -- -- ~0.7RC -- -- ->| |<- | |
OUTP | | | |
------- --------- ------ | ||||
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Posted by Fred Bloggs on February 28, 2005, 4:44 pm
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Terry Pinnell wrote: > I'm sure there must be a smarter way to do this than my first design.
> I want to produce separate +ve going 12V pulses at the leading and > trailing edges of a low impedance 12V input. > > My first draft looks too complex: > > - Use R/C/diode edge detector to produce OUT 1. > - Also take input to half a 4013 to produce FF > - Logic NOR the input with the inverted FF > - Use R/C/diode edge detector to produce OUT 2 > > Here's the timing chart: > http://www.terrypin.dial.pipex.com/Images/2From1.gif > > I think those crude output pulses should be adequate without further > cleaning up, as they go to the respective Set and Reset inputs of a > simple 4001 bistable. Of course, squared up outputs would be a bonus; > I might do that anyway if I have any spare 4001 gates. > > For the curious, it's an add-on for my curtain controller, to open and > close them either at dawn/dusk or at specific times of day. > > Any simpler way to achieve this please? > This should be more in line with what you want: View in a fixed-width font such as Courier. 4070_ +---------------- | | | >--+------>OUTN
| | +-/ /__/ | |
IN>---+-[R]-+--| o --+ +-| o-->OUTP
| |/ |/
[C] 40106 40106 | | --- ------------ | | | | IN ------- ----------- ------- --------- ------- | | | | OUTN | | | | -- -- ~0.7RC -- -- ->| |<- | |
OUTP | | | |
------- --------- ------ +--------------------------+ 4001 | _ +- +---------------- | o-->OUTNN
| | +-/ /__/ |
| | | >-+---/__/ IN>---+-[R]-+--| o --+ 4070 |
| | |/ |
| [C] 40106 | | | | | | | | --- | | | 4011 | | __ +----------------------------| | | | o-| o --->OUTPP
+---|__/ |/
40106 ------------ | | | | IN ------- ----------- ~0.7RC -- ->| |<-
OUTNN | |
-------------------- ------- ~0.7RC -- ->| |<-
OUTPP | |
------- ------------------- | ||||
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Posted by Fred Bloggs on February 28, 2005, 4:48 pm
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Fred Bloggs wrote: scratch that- do this: View in a fixed-width font such as Courier. 4070_ +---------------- | | | >--+------>OUTN
| | +-/ /__/ | |
IN>---+-[R]-+--| o --+ +-| o-->OUTP
| |/ |/
[C] 40106 40106 | | --- ------------ | | | | IN ------- ----------- ------- --------- ------- | | | | OUTN | | | | -- -- ~0.7RC -- -- ->| |<- | |
OUTP | | | |
------- --------- ------ +--------------------------+ 4001 | _ +- +---------------- | o-->OUTNN
| | +-/ /__/ |
| | | >-+---/__/ IN>---+-[R]-+--| o --+ 4070 |
| | |/ |
| [C] 40106 | | | | | | | | --- | | | | | | 4001 +------------| o ------------ |/ | | o-->OUTPP
40106 +---/__/
------------ | | | | IN ------- ----------- ~0.7RC -- ->| |<-
OUTNN | |
-------------------- ------- ~0.7RC -- ->| |<-
OUTPP | |
------- ------------------- | ||||
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