PV Pak Preview

[KoS]

Anyone have any good tutorials on how to etch a PCB board? I have found a few on the net, but I was hoping to find a tried and true method.

Check Rat Shack. They sell the copper boards and chemical kits and the tape you use to etch your schmatic. They also have a pen if you feel lucky. I used to have a dremal drill press that was awsome for making the holes. It's prety simple realy.
1. Lay out the pattern using the tape and stickers on the copper board.
2. give it an chemical bath ( forget what the chem was) and all the copper will disolve except where the tape was.
3. Rinse
4. Drill holes
5. solder


This is a great idea about the touch switch. I was just thinking the other day about a lighter that my grandpa gave me years ago that had the 2 metal bars you rubed your finger across and the lighter lit.

 

[Vapinginjapan]

Can I point out an unintended weakness of this switch design?

If it's anything like the screens in the iPod touch, which work on a similar principle (electrical conductance of screen contact) this will *not* work while wearing gloves. Ah well.

 

[nash076]

Can I point out an unintended weakness of this switch design?

If it's anything like the screens in the iPod touch, which work on a similar principle (electrical conductance of screen contact) this will *not* work while wearing gloves. Ah well.

Sure it will! buy a pack of Doublemint gum, and put the wrapper around your thumb, foil side out.

Ta da!

Nash

 

[nash076]

The only thing I could possibly think to add (and forgive me if it's there and I didn't see it) is a small LED to indicate when it's activated. Call me weird, but I always like having one of them.

Nash

 

[kender]

Laredo7mm use eagle (free) to lay out the board
print it using a laser printer on glossy paper
Iron it on the copper board
etch it with muratic acid (pool store) and hygrogen peroxide
all steps can be googled for step by step

edit to add:
You already have the board designed
If you use that shiny magazine paper to print with the laser printer
it transfers very easy, It gives nice clean lines

 

[RayJ1]

This device will need a dedicated charger if using li-poly batteries. The li-poly's pack alot of power and are very light weight. The chargers for these things are abit pricey. The cheapest I've seen are about $50.00.

 

[Laredo7mm]

This device will need a dedicated charger if using li-poly batteries. The li-poly's pack alot of power and are very light weight. The chargers for these things are abit pricey. The cheapest I've seen are about $50.00.

You are right on the dedicated charger, but you shop at the wrong places. The charger I bought was $9.99. Simple plug in charger with auto shut off when the li-poly is charged to 4.2V. Also the battery is fully protected with its own PCB.

 

[Laredo7mm]

...If you use that shiny magazine paper to print with the laser printer it transfers very easy, It gives nice clean lines

Yeah, I was just looking at some of those how to's using magazine paper. That will definitely be what I try first.

 

[Laredo7mm]

Here is the almost done circuit board. Amazingly, it wasn't nearly as bad as I thought it was going to be. Sorry for the blurry picture, but it is as good as I could do with the camera on my phone.

 

[kinabaloo]

Impressive progress. Well done !

What is the highish wattage, low ohmic value resistor for, seen at the bottom? Seems to be on the power input line?

 

[cekte]

Great work!

I think you are onto an excellent design. Please take this only as constructive criticism..

However, have you considered that anything else also conductive will complete the circuit? IE: change, reaching in pocket, keys, liquid, setting it near/on something conductive, etc. While I realize this may seem trivial or 'common sense', it may pose problems later on..

Any which way, Keep up the great modding!

EDIT: Sign me up for a PV Pak, if you do decide to make more than the initial prototype!

 

[Laredo7mm]

...have you considered that anything else also conductive will complete the circuit? IE: change, reaching in pocket, keys, liquid, setting it near/on something conductive...

I have considered that, but to be honest, it is not going to be a problem for me. It won't be carried in the same pocket as keys or change. Setting it near something conductive won't complete the circuit. It will have some drawbacks, but for me, it will be better than a momentary switch.

Hopefully tonight I will be able to finish the board (just need to add the jumper wires) and give it a test run to see if I designed the circuit correctly.

Thanks for all the great feedback guys.

 

[kinabaloo]

What is the highish wattage, low ohmic value resistor for, seen at the bottom? Seems to be on the power input line?

 

[Laredo7mm]

What is the highish wattage, low ohmic value resistor for, seen at the bottom? Seems to be on the power input line?

That is my mess-up, you were not supposed to notice that.


I had to change the circuit a bit to try and make sure my logic high and low would work right for the touch switch. Unfortunately, I already placed my order for all my parts and I didn't want to pay $5.00 shipping for a $0.14 SMT resistor, so I bought some from Radio Shack.

The resistor in question is a 1/4 watt 1 Mega Ohm resistor. It is going from a logic input to the DC power in jack shield and then to the ground line. That logic pin is the one that goes high when the tough switch is activated to send the current to the atomizer. When the touch switch is open, then the pin can go to zero (low) and the current will stop flowing. I think the 1 Mega Ohm resistor is there so that the current will take the path of least resistance through the logic pin and not to ground when the touch switch is closed.

Well, that is what I am hoping happens.

 

[kinabaloo]

It looked like bown black green, but it also looked too big to be 1/4w; but that was just because the photo is enlarged, i guess.

The purpose is sensible.

I think this mod is a first for the extent of electronics involement

 

[kender]

That board turned out great
Can't wait for the completed mod
Great work!

 

[morphector]

Really good mod, hope to see more great ideas like that one in the future...

I'm currently starting to think about building my own pcc, already ordered my parts....

Are you planing on giving plans for open-source or planning on selling it?

 

[SuperChicken]

That looks awesome
I seen a couple ideas on here for making the board. What method did you use to print and etch it?
Are you going to do a howto?

 

[Laredo7mm]

So, I am working on version 3. I had some bad circuit design on the previous two boards. I wish I knew electronics better, but hey I am getting some really good soldering practice in. I didn't even need to use the solder braid on the last board to remove excess solder from the 16 pin IC.

The other issue I am having is that after putting power to the circuit a couple of times, my contacts for the plus and minus are becoming continent. Is that the right word? Basically after a few times running the board and checking the 5V output, it stops working, and when I check for continuity, the plus and minus battery inputs show continuity.

Either I have something drastically wrong in my circuit design, or I am accidentally shorting the output and frying the IC.

Making the PCB is about the easiest part of the wholes thing. I am using the magazine paper transfer method. It was mentioned earlier in this thread and there are some good tutorials out there on the net already. I have also started using a program called "DipTrace" to do my PCB layout. Nice little program. This is what makes me lean towards me frying the IC by shorting the output since DipTrace automatically draws the traces for your based off of the circuit schematic you draw. I am using the schematic for a basic circuit that was included from the chip manufacturer, with some slight modification.

So, I have to order some more parts, and then get busy again. I will let you all know how it goes. So far, I can get the 5V output, but the touch switch is not working yet.

 

[kinabaloo]

I always use sockets/holders for ICs - solder the socket and connect the IC into it after it's cooled down.