Let's Make Robots!

need help with new picaxe board

 

in an effort to learn about using the picaxe board, I'm trying to blink an LED on a new board.  I think I've got it set up correctly (see pict).   The + leg of LED goes to digital out pin 3, the neg side of leg is connected to 330 ohm resistor which then goes to a ground pin. The code I typed in is main: high 3 pause 1000 low 3 pause 1000 goto main.  I downloaded the program to the board and nothing happens (no blinking led).  When I pull out the connector to pin 3 and plug it into a V1 pin, the LED lights solid.  Any suggestions what I'm doing wrong as far as getting it to blink.  Thanks. I appreciate the help.

 

AttachmentSize
circuit.jpg88.29 KB

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.

Chris.... thanks once again.  That worked! I hooked up the LED positive lead to V1 and the neg LED lead (with the resistor) to the pin 3.  I thought (wrongly, I see), the ground pin would be neg and the output pin 3 would be +. I didn't consider with pin running through the darlington chip... that would be ground.    

With no resistor, it pulls 3.79 v and with the resistor to light the LED, pulls 1.79 volts.  So.... all is well.  Thank you Chris.

I guess maybe this is what Balderbraa was alluding to... I just didn't get it at the time.  Thanks, both.

The meter should not go from pin 3 to ground, it should go to pin 3 and +. If you are using the darlington chip on the 28x board, you will be "switching ground". When the darlington gets a high signal, it connects its output to ground --not Vdd. Test again with your meter, pin3 and +.

Same with your LED, positive goes to positive and negitive goes to the darlington output.

Thank you for the suggestion, Balderbraa, but no love there.

I pulled out the LED and put a meter on pin 3 and ground.  I changed the time the pin received juice from 1 second to 6 seconds...high for 6, low for 6..... and sure enough.... the pin received .617 volts for 6 seconds.... then 0 for 6 seconds.... so it seems the board is cycling...however, .617 volts is not enough to light up the LED.  Why would it be receiving such a low voltage?  Is there some adjustment I would make somewhere?  Thank you for the help.   Am I thinking about this correctly?

FOLLOW UP:  I tried the same with an arduino board (cycled on and off for 6 seconds... this gave time to get a voltage reading on the LED).... On the arduino pin, when high it pulled 2.26 volts.... then off for 6 seconds.... so why is the picaxe just pulling .617 volts on the pin???

Try to connect the V+ lead from the LED to V+ trough the resistor and the ground to output 3 on the board.