Society of Robots - Robot Forum

Electronics => Electronics => Topic started by: legobot on February 12, 2010, 11:05:35 PM

Title: $50 Robot Electronics- Status LED
Post by: legobot on February 12, 2010, 11:05:35 PM

I'm building the $50 Robot, and I'm at the stage where you test the electronics.  I have connected power to it, but the status LED isn't lighting up.  I have checked the dot schematic, and it says that the resistor the LED is connected to should connect to Pin 6 on the Atmega IC.  The instructions say to connect it to one of the digital outputs, though.  I'm getting really confused!

What should be connected where?  What should happen when I turn on the power?

If anyone could please answer these questions, I would appreciate it very much.


legobot

Title: Re: $50 Robot Electronics- Status LED
Post by: Trumpkin on February 12, 2010, 11:11:28 PM

The status LED will not light up until you program the microcontroller.

Title: Re: $50 Robot Electronics- Status LED
Post by: legobot on February 19, 2010, 03:02:31 PM

Thanks Trumpkin!

So why is the LED connected to a digital output port?  Won't the LED only light up if there is power going to that port?


legobot

Title: Re: $50 Robot Electronics- Status LED
Post by: SmAsH on February 19, 2010, 03:16:58 PM

No, the led lights up when the port goes low, thus letting power from vcc through the led, though the pin to gnd.

Title: Re: $50 Robot Electronics- Status LED
Post by: legobot on February 19, 2010, 07:53:16 PM

Quote from: SmAsH on February 19, 2010, 03:16:58 PM

No, the led lights up when the port goes low, thus letting power from vcc through the led, though the pin to gnd.

Ah ha!

Thanks!  That makes sense.


legobot