Microcontroller controlled by pushbutton for LED flashlight

[Arouse1973]

A Tormach PCNC1100.

Ah, a little bigger than expected and a bit pricy. LOL

 

[TenderTendon]

Steve,
I went to populate the board, and there's some problems. The Switch pads are way too far apart. There are no pads big enough for the schottkey diode. The pads for the PIC are too close together (width and length). I just noticed that the cut board dimension is 30mm x 52mm. In post 84, you mention the board is 40mm x 70mm. Did something get screwed in the conversion? Here's a pic of the PIC next to the pads and the switch inside the pads.

 

[(*steve*)]

oh :-(

It looks like a scaling issue (other than the switch).

If you can confirm that the microcontroller is actually in a SOT-23-6 package, that will confirm the issue.

The switch can be made to fit, you just want opposite corners connected to those two traces. I think you can accomplish this by rotating it a bit.

The microcontroller *might* be able to be fitted by soldering the middle pair of legs on ot near the pads and the outer legs to the tracks. WireWrap wire is great for making small jumpers.

The row of circular pads are placed on 2.54mm (0.1 inch) centres. This is probably the best thing to check for scaling.

If you have actually made it smaller than designed, I am even more in awe of your milling machine!

 

[TenderTendon]

Yes, the PIC is SOT-23-6. I tried soldering the PIC to these pads. If it is possible, it's way beyond my soldering skills. Here's a screenshot of AutoCAD 2007 displaying the dimensions.

 

[TenderTendon]

OK, I scaled the drawing to get the circular pads on 0.1" centers. I also adjusted the pads for the switch and Schottkey diode. I also got rid of a few things i don't need right now to reduce cutting time. I'll cut this one tomorrow.

 

[(*steve*)]

Looks great. Out of curiosity, how long does it take to mill this? And also, is this your personal mill (i.e. at home)?

 

[Arouse1973]

Looks great. Out of curiosity, how long does it take to mill this? And also, is this your personal mill (i.e. at home)?

I see a proposition brewing here or you want one.

 

[TenderTendon]

Looks great. Out of curiosity, how long does it take to mill this? And also, is this your personal mill (i.e. at home)?

It took approximately 20 minutes. My spindle can only do 5K rpm, which is way too slow for a .004" engraving bit. To run this bit properly, I would need a 80K rpm spindle. To compensate, I have to really slow down the feed rate. With the right spindle it would take 1-2 minutes. Yes, this mill is at my home, along with other machines. Not really personal though, as I make my living with them.

 

[TenderTendon]

The board is finished and populated. I didn't see any polarity markings on the cap, so I assume there isn't any. I am able to communicate with the PIC. When the PIC is powered up with the PICKIT3, there is a stray +1.5v on the MOSFET gate. I assume that is because there is no I/O's or soft pullup/down's configured. I didn't put power or a load on the MOSFET, as I assume that 1.5v would put it in a high resistance on state.

 

[Arouse1973]

Update: I have a demo PCB made with and LED to indicate power to the LED module. I have some code running which is working but it may need some fine tuning. I need to connect the circuit to something that will mimic the LED module so I can test to see if the hold up capacitors is working. I just then need to add the sleep commands and I am done. I'll try and post the code and a picture of the PCB over the weekend.
Adam

 

[TenderTendon]

Sounds good. Just use a 330 ohm resistor for the load/power supply. That will be a good test.

 

[(*steve*)]

Nice work Jeff.

Yeah, without the pin connected to the mosfet's gate being positively driven either way, don't apply power across it.

I'll check again, but I'm almost 100% certain that powering the circuit from the programming pins is safe. (yep, confirmed)

I think Adam is going to be able to get the software working for you (Thanks Adam) so I'll probably go into lurker mode unless I'm needed.

 

[(*steve*)]

I see a proposition brewing here or you want one.

I want one!

But seriously, I'm comparing the time taken to mill compared to laser cut and etch. Obviously, with the correct tools milling is faster as my laser cutting of this board would take longer than 2 minutes, and then there's the etch...

This is (for me anyway) a seriously high end piece of equipment (and I guess you might say the same about a laser cutter) and not the sort of thing I'm likely to have access to any time soon.

Jeff, what is the thinnest gap in copper that you could mill out, and what do you think would be the thinnest track you could reliably cut?

And, if you don't mind the questions, what do you use this for in your work life?

 

[TenderTendon]

The smallest end mill I have ever seen is 0.1mm, so that would be about the smallest gap. There may be a smaller tool out there, but I'm not aware of it. I would guess that the thinnest track would be about 0.3mm. I would bet that anything smaller than that would break from the stress of the cutter. PM sent about the rest.

 

[Arouse1973]

I have been testing the software and I am not happy with its turn off responce. So I am re-writing the software. This little PIC is ok but its quite basic so a few instruction I am used to are not there. There are not any interrupts so switch checking is a bit different. Be a bit longer sorry.
Adam

 

[BobK]

Adam,

Which microcontroller? The PIC10F320/322 has the extended midrange core, and comes in 6-pin SMT.

Bob

 

[Arouse1973]

Adam,

Which microcontroller? The PIC10F320/322 has the extended midrange core, and comes in 6-pin SMT.

Bob

Hi Bob
I am using the 10F200 which is the one Kris was using. Not my first choice personally, a bit limited but I have them now so just have to make the best of them I can.
cheers
Adam

 

[BobK]

Okay.

At 67 cents Qty 1 vs 50 cents, I can see that!

Bob

 

[Arouse1973]

LOL I just wanted to carry on using the same PIC as Kris used, but yeah bit of a brain fart, sorry Kris . I do have a question however. I am having trouble getting TMR0 to run. I have set the option reg to 10000111 do I need to do anything else to get it working? I have never used the 10 series before, have you?
Cheers
Adam

 

[TenderTendon]

LOL I just wanted to carry on using the same PIC as Kris used, but yeah bit of a brain fart, sorry Kris . I do have a question however. I am having trouble getting TMR0 to run. I have set the option reg to 10000111 do I need to do anything else to get it working? I have never used the 10 series before, have you?
Cheers
Adam

I pray to God this question isn't directed at me...