20 de diciembre de 2009
The circuit is pretty straightforward. Tha main challenge is try to fit everything in a single sided board. GLCD connection is rather difficult (I suppose this is intended to be built around multiple layer board).
This is the eagle schematic. Sorry for the mess...but as my wife says...I am a mess myself:
Main board can be updated with more powerful microcontrollers, like PIC18f2550, or other 28 pins PICs just by increasing XTAL speed and changing capacitors to 27 pF.
The main issue was try to fit everything inside a 12x8 cm single sided board.
The final solution was to fit the LCD in the bottom layer of the PCB, jut inverting the pinout, so the micro and XTL rest in the top layer. This saves at leat 1 cm height in the final board. With this configuration buttons are soldered also in the bottom layer...just like SMD components.
In the end is a really flat device (at least for the 80's standards ;OD).
PCB is homemade built. For insolating the photosensitive board I use a DIY insolator box with two 20W low consumption bulb lights. I get the job done in just 3 minutes.
For the revelating part i use Caustic (NaOH), at 20 g/l concentration.
Then the board is etched with a mixture of HCl (20% in water) and percarbonate (solid). Perborathe would do the same.
As ou can see for me the PCB is detailed enough, and costs are kept to a minimum (but still higuer than requesting the PCB from PCBcart!!).
Repro boards I am using, single sided, have a photosensitive layer in the top, so a kind of serigraphic layer can be done. Process is exactly the same and is done at the same time than the main board.
(This last pics correspond to PIPER v 2.0, that will integrate batteries inside the main PCB board, so total height will be halved).
La última actualización de este sitio fue el: 09 de diciembre de 2009