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Remote trigger, momentary switch, soft start PCB (for First Watt or other projects)

f96569aa92ac4550ebb51afe3023df25.jpg

Done, thanks to Mfly and loek. I used same LDO as loek, 22uF as loek suggested and datasheet imposes. It outputs 12 volts perfectly, doesn't get much more heater than warm.
For the other board, I'll use less fancy resistors.

Inviato dal mio D5803 utilizzando Tapatalk
 
Always better to use stock parts then pay for new ones! Good that this one is working now.
Regards, Loek
I've been trying to, but I was missing many parts and ended ordering them as per BOM... Then noticed I had some spare caps for softstart delay - I would have saved a pair of euros...
I didn't have to add the cap as you did.
Switching is somehow a bit sensible, but I have to test it better.
Thanks again,
Marco
 
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Hi there, I'm upping this thread again for bit of help.
I've been using this circuit for a while now; just recently, I've forgot the main power inserted and... after some minutes, the master powers ons!
No modifications to the BOM, except the LM2940-12 and the consequent 22uF and no diode in D11.
Anyone experiencing this?

TIA!

Marco
 
Hi there, I'm upping this thread again for bit of help.
I've been using this circuit for a while now; just recently, I've forgot the main power inserted and... after some minutes, the master powers ons!
No modifications to the BOM, except the LM2940-12 and the consequent 22uF and no diode in D11.
Anyone experiencing this?

TIA!

Marco

Dear Marco,

I came to the conclusion that the flip/flop circuit is quite sensitive to external devices switching power. Mine would come on when the motor of the of my projector screen switches of. For me the solution was to ground the circuit. So try leading a wire from the GND terminal to your earth GND.

Hope this helps!
 
Dear Marco,

I came to the conclusion that the flip/flop circuit is quite sensitive to external devices switching power. Mine would come on when the motor of the of my projector screen switches of. For me the solution was to ground the circuit. So try leading a wire from the GND terminal to your earth GND.

Hope this helps!

Thanks Mfly! I'll try and report back.
 
After 2 years and installing several boards in my own projects and other equipment some observations and changes:

-The remote out solution gives an 'always on' situation when using the board linked in 'slave mode'. So if you have multiple boards linked and experiences issues that the slave board is always on:

  • Remove 'T1' and connect the sleeve pin from the 'remote out' connector directly to GND (you can connect the 'collector' and 'emitter' holes from T1 you just removed).
  • Then cut the trace between the tip pin of the 'remote out' connector and 5v (the trace between the tip pin and R12)
  • Finally connect the tip pin between R13 and D4

This way you directly use the trigger signal from the remote in.

-As Loek (thanks for the solutions and drawings) and I already mentioned in earlier posts: the 555 is quite sensitive to outside influences (RMI, spikes on GND or supply, etc.). On most boards adding 0.1uF between V+ and ground is enough, but as Loek mentions sometimes and additional cap between the trigger pin (pin 2) and GND is warranted. In my case I have no false triggers anymore and have now linked 4 devices with this board after my pre-amp. And don't forget to connect the GND of the board to your chassis!
 
......-The remote out solution gives an 'always on' situation when using the board linked in 'slave mode'. So if you have multiple boards linked and experiences issues that the slave board is always on:

  • Remove 'T1' and connect the sleeve pin from the 'remote out' connector directly to GND (you can connect the 'collector' and 'emitter' holes from T1 you just removed).
  • Then cut the trace between the tip pin of the 'remote out' connector and 5v (the trace between the tip pin and R12)
  • Finally connect the tip pin between R13 and D4

This way you directly use the trigger signal from the remote in....

If you don't have multiple boards linked, is it still necessary (or better) to make the mod described above?
 
I'm confused. The capacitor you link to is C5 (also in the BOM, which should be an X-type / XY type). C6 and C10 in the BOM link to:

MKP2F021001B00JI00 WIMA | Mouser Nederland

Which is a small film cap with lead spacing of 5mm and 3 mm width which should fit. I'm not exactly sure about the space available (it's been long ago), but the lead spacing is 5mm if I look at the to-220 package (IC1) next to it.
 
I'm confused. The capacitor you link to is C5 (also in the BOM, which should be an X-type / XY type). C6 and C10 in the BOM link to:

MKP2F021001B00JI00 WIMA | Mouser Nederland

Which is a small film cap with lead spacing of 5mm and 3 mm width which should fit. I'm not exactly sure about the space available (it's been long ago), but the lead spacing is 5mm if I look at the to-220 package (IC1) next to it.

Ah. I should have checked the BOM in your first post. I was going off an older BOM I printed out a couple years ago. Maybe it was updated? No worries though. I see the error of my ways. ;)