On 2/4/2020 6:01 PM, amdx wrote:
On 2/4/2020 2:13 PM, Andy Bennet wrote:
On 04/02/2020 16:54, amdx wrote:
On 2/3/2020 11:09 PM, tabbypurr_at_gmail.com wrote:
On Sunday, 2 February 2020 18:36:14 UTC, RobH wrote:
On 02/02/2020 17:18, amdx wrote:
On 2/2/2020 11:08 AM, RobH wrote:
There is a photo I took here:
I don't know why, but all I can pull up from the link are my
Anyone know how I can view his picture?
I know why, you have to log in, but I have shared it now with the
address I see here.
I don't know how to make it public yet.
post it on a sensible image hosting site
Would be interesting to many people see a video of this thing
actually working, including clear view of the input side of the 741.
I'm working with him offline.
He now has a working one shot 555, so that is solved.
For a start I'm doing just ldr-resistor with the center connection
to Pin 2. I realize there is a level transition problem with a
single neg pulse to Pin 2. However we are working towards that.
We are just now adjusting the resistor-ldr to drop below 1/3Vc to
trigger the 555. As built is only dropped to 4.3 in the dark, so he
is now adjusting the resistor value.
Next we will need to differentiate the negative going signal from
the ldr. I do see a problem with a slowly decreasing light situation
and we may end up with some fast switch between the ldr and the 555
I think he has limited parts, so we may have to do something with the
741 or two PNPs. I think I saw he only has PNP transistors.
If you have an Idea to make cause a fast switch from a slow
I'm open to ideas. He has the 741, so can you make that work, or two
If this is daylight to sunset sensor, we will need a fast transition.
Turn the 741 into a schmitt trigger, rather than trying to explain see:-
Thank you, I did find a video showing that, but this page is much
I may need a little more input, I have a voltage the sets at 5V, then
drops to 2V. A negative going pulse. That is the 555 trigger on Pin 2.
I need the output to go low when the input goes low.