OpenSource PIC Based LCD Watch

[Smartie]

Hey guys,

I'm developing a open source watch and my schematic looks good so far.
but designing the PCB is difficult as I've only designed one real PCB before and that was using through hole components.

This PCB is using rather small SMD parts and I would like your feedback on it as I would really like some expert advise on it.

Parts used:
PIC24FJ64GB004
MCP73833
TC1071
Nokia 6100 LCD
Right-Angled Buttons.
Li+ 110mAh battery

Notes:
TC1071 is a low power adjustable LDO.
MCP73833 is a Li-ion battery charger.
The 8pin header on the left is a header to a wireless transceiver.
On the board, the LCD is on the bottom while everything else is on the top.

Any feedback is highly appreciated!

Cheers
Roman

 

[Smartie]

Just a quick note, the mcp73833 and tc1071 was not in the library so I made them myself

 

[ericgibbs]

hi Roman,
As per our chat.

 

[birdman0_o]

Out of curiosity how are you going to program the SMD pic?

 

[Smartie]

That's a good question Mike lol, I have a PicKit3 coming in the mail very soon that I will use, but how should I connect it?
I only need to program the PIC once as It will be using a USB boot loader so I don't really want to solder a 5 pin header to the board

 

[Smartie]

Maybe I could use Pogo Pins?
An Error Has Occurred!

 

[BeeBop]

That's a good question Mike lol, I have a PicKit3 coming in the mail very soon that I will use, but how should I connect it?
I only need to program the PIC once as It will be using a USB boot loader so I don't really want to solder a 5 pin header to the board

How about leaving pads for the programming leads and making a cable which is soldered to the board to program, then de-soldered and removed?
Edit: Great thread, by the way.

 

[Smartie]

Update!

I've taken in feedback from everyone and I've re-done the layout of the board.

Now this is what I call art work

Edit: shoot, I forgot to add headers for ICSP... silly me

 

[3v0]

You might think about putting the ICSP pins on a bit of PCB that can be snapped off after the PIC has been programmed. If you use a boot loaded you only have to program the chip via the ISCP once. Keep the ICSP attached during development.

 

[Smartie]

Thanks for the good idea 3v0

I've done a lil bit of research into power requirements (no idea why I didn't do this in the first place) and found that the LCD draws quite a lot of power.
So, the LCD Vdd pins will be behind a transistor controlled by the uC so the LCD can be switched off when not in use. But...
The LED back light requires 7V and is recommended to use 40mA... my Li-ion battery only outputs 3.7V so this is a no-no

I'm going to research into LED drivers and hopefully find a solution that's power efficient

Cheers
Roman

 

[Gayan Soyza]

Hi Roman your idea is ok.But for me the design is a complete waste of time.The parts are unfamiliar,too hard to find & very expensive.Its too much for a clock.

When it comes to open source there should be minimum of parts & must be available in all over the world.

May be I'm wrong tell what are the options you have in your clock?