LDR, photodiode or?

MrDEB said:

GETTING THE HANG OF THE EasyEDA
need to figure out how to put a single row of 5 holes for the ICSP port (footprint same as a 5 pin header but don't need to order the header.
have all the port pins with resistor(603) and led(805).
need to configure the LDO regulator and pad for the USB smt socket (micro B)
don't really want the PIC on the front but only way to have it assembled on one side only.

Click to expand...

you can place it yourself on the backside. Just list it as "do not populate" in the BOM.

"A single row of 5 holes for an ICSP port" is called a header, with pins on 0.1" pitch. At the risk of stating the obvious, you won't look for this on the SMT parts library web page – it's not an SMT part.

Look for a tutorial on selecting components.

A USB power supply provides 5:volts. A 5 vollt regulator is unnecessary and in fact will not work when supplied with 5 volts. Best case scenario is you might get 3 volts of the the regulator. Or maybe nothing. Somehow, datasheets don't cover being stupid. Please don't include one.

The PIC in the TQFP package is pretty small. Putting it on the back of the board kind of defeats the purpose of having the board assembled.

Perhaps you should consider having just TWO boards assembled (the standard options are 2 or 10) as a test, and then have 10 assembled after the design is proven. You'll have to pay the service fees and shipping twice, but you'll save the cost of populating 10 boards that don't work.

I realize using a 5v regulator with 5v input won't work.
Planning on 5v in 3.5 or 3.8 out.
concerned the USB ac adapters are not real accurate and using a voltage reg. should alive the issue.
Planning a LDO regulator.
will look at the component selection tutorial if I can get it to load.

5 volt USB adapters strangely put out 5 volts. Who'd have thought. They are designed to power expensive devices, and there is a tight tolerance spec.

But if you want to add more parts, don't forget the caps on the input and output. And be sure to include a large copper area for heat-sinking. Adding unnecessary heat generation in a device used in a Christmas tree sounds incredibly foolish to me.

duly noted

slight change in plans. Putting the USB receptacle on back of board along with the pic.
Don't need the amount of memory in the 18f46k22 at $3+ each. Have 20 of the 18f43k22 on hand. COST IS A FACTOR
Have no real issue in soldering the pic but looking how to edit the foot print in Easyeda.
Have desired footprint in Diptrace.
After configuring the board outline, I see I need more LEDs so going with 3 LEDs in series each port with a generous resistor.

MrDEB said:

slight change in plans. Putting the USB receptacle on back of board along with the pic.
Don't need the amount of memory in the 18f46k22 at $3+ each. Have 20 of the 18f43k22 on hand. COST IS A FACTOR
Have no real issue in soldering the pic but looking how to edit the foot print in Easyeda.
Have desired footprint in Diptrace.
After configuring the board outline, I see I need more LEDs so going with 3 LEDs in series each port with a generous resistor.

Click to expand...

now I'm confused, what is the forward voltage of the three LEDs you are putting in series? Even a red LED at 1.7v each is 5.1v total. Then add the voltage drop of your resistor and then there is no way to power with a USB adapter and you'll need 4 AA batteries to get to 6v and then a voltage regulator. Or am I missing something?

MrDEB said:

...looking how to edit the foot print in Easyeda.
Have desired footprint in Diptrace.

Click to expand...

What GopherT said! 3 LEDs in series won't work at 5 volts. Even 2 white LEDs, with a forward voltage of over 3 volts, won't work in series.

Regarding finding the right components and footprints, the library of parts in EasyEDA is huge. For common parts, there is little chance you have to "edit" anything. About those tutorials.....

To find symbols and foot prints, search the iibrary.




Fill in the part # you're looking for and click the magnifying glass. Since you're not having this part assembled by JLC, select LCSC as the source.




Select the appropriate package and plop it on your schematic.

If searching on 18F43k22 doesn't return the right package, you can expand your search. Remember, the '43, '44, '45 and '46 versions are the same chip, with different amounts of memory, so searching on a different version may yield more results. Also, selecting SYSTEM instead of LCSC. This adds "user contributed" parts to the search. Use caution with user contributed parts and verify accuracy of the symbol and footprint.




Finally, if all else fails, symbols and footprints can be imported in a number of formats. Digikey and Mouser provide these for many components. You can download a file, use the provided tool to create the symbol and footprint in Eagle format for example, and import it in to EasyEDA. This is at most a five minute process, but way beyond what I have the patience to explain here.

Regarding those tutorials, EasyEDA has numerous videos and lots of help in their forum.

If you're not going to take the time to learn to use EasyEDA, I suggest that you NOT use JLC to assemble your boards. For a $7 engineering fee, you get next to zero help. If you can't be bothered to understand the process and the rules, you'll end up with an expensive pile of crap. Or at least make a test order of 2 boards first.

I am using JLC for assembly but the tutorials are not loading up? been using youtube for tutorials.
going to experiment using a different schematic and import my TQFP footprint?
As for the LEDs, using hopefully blue and white. need more research? for sure.

Why are you importing a TQFP footprint???I

If you LOOK AT the second picture I posted, the 3rd item is a PIC18F43K22 in a TQFP package. Click on that part and drop the part on your schematic. When you lay out the circuit board, the correct package will appear.

Why didn't I just roll over and go back to sleep at 5am instead of trying to help? I'd like to think you'd take a few minutes to look at and understand the point of replies that took half-an-hour to create.

Regarding LEDs in series, I don't know what research you need to do. Here is an excerpt from the datasheet for JLC's basic blue LED.



Of interest is the line labeled FORWARD VOLTAGE. It varies from a minimum of 2.5 volts to a maximum of 3.1 volts. Don't misunderstand the meaning of this. Some of this type of LEDs may have a Vf as low as 2.5 volts. B]Some[/b] of the LEDs may require as much as 3.1 volts to laminate. Most of the LEDs will turn on in the middle of that range, say 2.7v – 2.8v. But you need to allow for a batch of LEDs that has Vf of 3.1 volts because the ones you might receive might all have a Vf of 3.1volts.

You can't put 2 LEDs requiring 3.1v each and expect them to operate on 5 volts.

The green and white LEDs have a maximum Vf of 3.7 volts. Even worse.

The forward voltage is based on the chemistry of the LED. Blue LEDs from any manufacturer will have very similar Vf parameters.

Your option for more LEDs is to drive several from each port pin in parallel. Each LED must have its own resistor, and the maximum current draw from each pin is 20mA.

MY bad, I failed to figure in the LEDs requirements.
rethinking where this project is headed. Either more LEDs plus resistors or put 3 LEDs in parallel using one resistor which is not a good idea anyway.
Other option is reduce the size of the star from 7"x 10" to 3.5"x 5". Reducing size will lower costs as well
I like Jons idea of more resistors.
NOTE: was drawing out schematic in EasyEDA and had LEDs already picked but now I find the ones I have in my schematic are discontinued so need different LEDs.
As far as the tutorials, I have trouble understanding the narrator. Youtube is my go to source for EasyEDA tutorial.

This tutorial looks pretty good and is reasonably easy to understand.

There is some confusion around red 0603 at JLC. I just got a board back where I used the one in the Assembly database. The safest bet would be to use a different size, like 0805 or select a 0603 LED from the extended list. This will add a one time charge of $3 for the board, which is far better then getting your boards back without the red LED positions populated.

Thanks I think I viewed that tutorial? will look at again
re thinking the LEDs and resistors and decided to go with 1 x 0603 1k resistors per led. = 10.59 ma per port.
reducing the board size as well

Adding one of these radar motion sensors could be interesting. The radar lets you add an LDR so it only activates in the dark. Also, the radar only activates when someone is present in the room. Use a timer on your microcontroller to keep the lights on for x hours or minutes after the last motion was detected.

They are available as low as $0.40/each on alibaba or about $1.25 each on Amazon in 5 or more units.

Those radar detectors are interesting devices. They will actually detect motion through a sheet rock & stud wall! I played around a little trying to get some directionality without any success.

Visitor said:

Those radar detectors are interesting devices. They will actually detect motion through a sheet rock & stud wall!

Click to expand...

I have a pack of five sitting in a box... somewhere! I'll get to them eventually.

Have you tried a Ferrite or iron powder inductor core to "focus" the beam?

Click to expand...

I tried mounting the sensor in shallow and deep cans, thinking that would protect the back side. Didn't make much difference. Cans were connected to ground.