12F683 Light Dimmer Problem (SOLVED)

[DavyJones]

Sorry about that strangely I could not find a non-polarized cap symbol and choose that one and forgot to flip it. Let me search in the program some more to see if I can find a non-polarized one. There are so many symbols mostly based on part numbers. Hard to find just general symbols.
David

I found one finally it's not in the CAP category either. thanks for catching that.

[DavyJones]

Circuit boards are in. I realize that this differs slightly from my schematic I uploaded. I added a PBO-1-S5 to the board to supply power and eliminate the need for a wall wart for power. The PBO is really small and supplies 5v and 200ma which by my calculations is more than enough for this project. Also there are a few extra components on here which were added as the recommended filtering for the PBO. C1, C2 and C3 could have been SMD and L1 but they were out of stock so I went with conventional cap's,inductor for this version. The 12F683 can be SMD too but I choose a socket so I can mess around with the code and swapping out the processor quickly. The other thing I messed up on was for AC-in and Light I wanted to use 2 up terminal blocks but wasn't paying attention when I laid those out so they won't fit without running into the other components so for this version I will solder directly to the board the AC-in and light. I do notice every once in a while as the light dims and get's brighter there is a slight "glitch" for a microsecond the bulb will blink. It is so random and slight unless you are staring right at the bulb it's unnoticeable. It's almost as if there was a spike on the AC but since it happens so infrequently I don't think I could catch this on my scope to see if that is what it is or something else. Once I put this together and do some testing I was going to modify my schematic to include the PBO and extra components used for the power section. If anyone is interested let me know I will re-up the schematic

David

[HenrikOlsson]

You might know exactly what you're doing and if so that's great but just in case you don't here are some comments meant in all friendlyness:

You're dealing with mains voltages here so you need think a bit about clearance and creepage distances between the two nodes (phase/neutral) of the mains itself AND between the mains and the low voltage section.

It looks like you're running phase and neutral REALLY (really!) close together and close to pins 5 and 7 on the AC/DC module (up along the right hand side of the board as shown in the photo) and also REALLY close to the output of the AC/DC module (I'm talking specifically about the pad for L1 which I'm guessing is the series inductor on the output).

There's a reason there's 0.2" between pins on the mains side and then 0.3" between pins OF the mains side and the secondary side of the AC/DC module. By then having pins/pads of components connected to the mains side in close proximity of pins/pads connected to secondary side you're throwing that nice isolation that the AC/DC module provides out the window.

Yes, there' soldermask on the traces and it helps but still, I would not feel comfortable with that - especially if I were to hand it over to someone else - friend or not :-)

Again, all meant in a friendly way!

/Henrik.

[DavyJones]

Henrik, Thank you. You make very good points here. this is version one and I did not worry about some of those distances. In v2.0 I will take into account your suggestions to properly space the AC. I crammed things close together not taking that into account so the board would fit into the box I had on hand. I'm going to take your advice on my next one and design it first then find a box it will fit nicely into. I did solder all the components on there and it does work however as you pointed out there are a few things I need to consider.
I appreciate the feedback.