Wednesday, October 26, 2011

PSoC3 Custom Board - Prototype soon

Phillip and I added few more changes,and looks like its finally ready for prototype.
Heres a shot of the board:
 click the image for a full size version

Drop a line in the comments if youre interested in the latest PCB files. 

PSoC3 Custom Board - Almost ready!

After my tests,I've finally got a chance to devote some more time to this project,so heres the result:
 click the image for a full size version

 I would like to thank Phillip Radner for his help and contribution to the design.

-Added the top layer copper fill,connected to the GND net,
-Added test points for all the important voltage levels on the board,
-Fixed the silkscreen and added the OSHW logo :)
-Ran the ERC and DRC,and fixed all errors that came up.I used the sparkfun DRU for that.
-Minor placement shifts and such.

I should probably add extra vias between the 2 layers.

Drop a line in the comments if youre interested in the latest PCB files.

Thursday, October 6, 2011

PSoC3 Custom Board - More changes

 click the image for a full size version
Heres the latest view of the PCB.Many changes from the previous version,which I'll quickly list.
-Removed the external DC jack.
-Removed zero ohm resistors,and added solder jumpers(from SparkFun's eagle library).
-Added the ground plane,which is of the "GND" net.(GND net is the USB's ground,shorted with the VSSA and VDDA using a solder jumper.)
-Changed the type of USB connector,since I had a bad experience with a miniusb one.Too small to comfortably solder,with an thick iron like mine.

And yeah,I've decided on a name - "EzPSoC3".

I'm still waiting for confirmation from Cypress on the ground plane placement,but other than that,it seems ready :)

Drop a line in the comments if youre interested in the PCB files.

Wednesday, October 5, 2011

Part of the Day - Magnetic Reed Switch

A very simple and elegant non-contact switching mechanism,which can support currents upto 1.2A (but look into datasheets for part specific values).

The device consists of 2 ferromagnetic contacts,parallel and overhanging,encased in a glass case(much like diodes are.) They range in length from 2.0 inches long to as small as  0.025 inches long.When the device is in proximity of a magnet, the two ferrous contacts inside the switch pull together and the switch closes.So,not terribly great switching times(~1mS),but useful nonetheless.

Theres an app note and working description at Sparkfun,click here to read it.(PDF) They also have it in the catalog(here),and can be purchased for $1.50 a piece.

Common applications include sensors and alarms.They can also be used for checking orientation of various objects(which have some magnet attached,so proximity would turn on the switch) etc.

A very detailed writeup on them,at