Led's on control panel

[PACKRAT]

Hi All
I’ve been away from the cnc world for a little while, And now trying to catch up.
I’m making a new control panel and wont to put led’s on it to show the state of different things,
Now I don’t want to draw too much power from the pokey’s so I’m making this circuit to use external power For the led’s, but I’m not too good at electronic can someone tell me if this will work? There may be 6 to 8 led’s on at the same time.
Also thanks to Borisz and Scott, this little device works grate, and a special thanks to Scott for his service to this Country.
Gary

[borisz]

Hi!

PoKeys can drive 8 LEDs without problem. Your schematics is OK.
You can connect 5V to PoKeys 5V also.
Also IC ULN2803 can be used, which can drive up to 8 inputs.
Also you can use these board: http://www.cnc4pc.com/Store/osc/product_info.php?cPath=54&products_id=265
Same board should be avaiable soon also on www.poscope.com

regards

Boris

[JHChoppers]

You can connect 5V to PoKeys 5V also.

Boris, what does this mean?  The PoKeys CPU is a 3.3V device, do you mean you can connect an external supply of 5V to PoKeys?

[borisz]

Hi!

Please look User manual and the pin description. You will see that there is a pin which can output 5V from PoKeys.

regards

Boris

[JHChoppers]

OK Thanks;  Use the the 5V output from PoKeys to supply the LED circuit VCC. 

The user manual indicates that 400mA is the MAX on that pin too, so you should be able to drive an MPG and several LEDs with this source.  Just make sure you keep it under 400mA total.