0

HELP!
Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.

by montag on Sat Nov 03, 2007 5:22 am

Max collector current for a Fairchild 2222A is 1A. Did the batteries get hot too?
montag
 
Posts: 60
Joined: Sat Jun 16, 2007 1:43 pm

by scifipirate on Sat Nov 03, 2007 7:33 am

no just the transistors
User avatar
scifipirate
 
Posts: 29
Joined: Fri Nov 02, 2007 10:18 am

by scifipirate on Sat Nov 03, 2007 8:32 pm

So is this thing just a lost cause now, or does anyone have anything else I could try?
User avatar
scifipirate
 
Posts: 29
Joined: Fri Nov 02, 2007 10:18 am

by adafruit on Sat Nov 03, 2007 10:45 pm

you could return it for analysis to adafruit and this one time we'll send a replacement kit...but it could theoretically happen again so its up to you.

adafruit
 
Posts: 12151
Joined: Thu Apr 06, 2006 4:21 pm
Location: nyc

by scifipirate on Sat Nov 03, 2007 10:53 pm

weeeeellll let me think about that
User avatar
scifipirate
 
Posts: 29
Joined: Fri Nov 02, 2007 10:18 am

by montag on Sun Nov 04, 2007 5:27 pm

Looked into what I did on my beater perfboard one.


Jump pin 4 to 5 to test the green LED. LED should stay lit while jumped. you did this.

if above works:
Jump pin 7 to pin 5 green led should light when button is pressed. Off when buton is relaesed.

Jump pin 8 to pin 6. This should make the IR leds light, verify with dig camera. Do not leave connected any longer than needed too much voltage. If this does not work your transistors or IR LEDs are bad.
If they do light something is wrong in AVR or Xtal.


Use a resistor to jump with but to lazy to figure out proper voltage drop. Might add that tomorrow. Use a 100 ohm resistor to protect the transistors and LED from to much voltage and current.

Test Power with meter.
black to ground:
Red to:
+ on IR LEDs = battery voltage ~3V
Pin 6 was about .5V Hard to read as it is a pulse.
transistor side of 47 ohm about 2 volts

remove AVR and test all grounds with ohm meter:
Battery ground to:
Emitters of transistors = 0 ohms
Center of crystal resanator = 0 ohms
ground side of switch =0
ground side of green LED =0
Use the schematic to test all ground points. ( Not an issue with yours it worked once so should be ok Just trying to make a test tutorial in general.



Thats about all you can test with out real test equipment.

When I did this and left the jumper in from pin 8 to pin 6, the transistors started to get hot. Likely your AVR is shorted out. The output of the 6 pin is way lower than the + rail that you are using to jump with.

My suggestion is get another AVR from adafruit and try it out. I think you will find it works. I got my transistors pretty hot and it still works after cooling off and reinserting the AVR.

Might want to make some kind of case for the board or coating it with something so it canot be shorted out or esd damaged again.

Edit to make more clear in red sorry I write like banned. Also see Mitches Post below!!!

Hope that helps to fix the :evil: thing.
Last edited by montag on Sun Nov 04, 2007 6:37 pm, edited 4 times in total.
montag
 
Posts: 60
Joined: Sat Jun 16, 2007 1:43 pm

by maltman23 on Sun Nov 04, 2007 5:57 pm

We are relying on the IR signal output from the microcontroller (pin 6) to be pulsing at a small duty cycle. When current from this output is applied to the 47 ohm base resistors to the transistors, the transistors are full on, and their is a huge amount of current flowing through both the IR emitters and the transistors (more than either can handle (though I haven't actually calculated how much). So, if somehow your microcontroller got into a funky state where pin 6 remained high, then that could have burned out some or all of the transistors, and/or some or all of the IR emitters. But the microcontroller should still be OK (if the transistors' bases all shorted to ground then there would be too much current being drawn from the micro's pin 6, but these chips are incredibly robust, in my experience).

In any case, if you short out pin 6 to pin 8 for the test that montag suggested (a good test), please be sure to do it quickly to avoid burning out any of the transistors or IR emitters (i.e., get your camera ready before shorting the pins).

Mitch.

maltman23
 
Posts: 134
Joined: Fri Jul 13, 2007 4:54 pm
Location: San Francisco

by scifipirate on Sun Nov 04, 2007 7:52 pm

cool cool cool, thanks for all ur help, I'm gonna go try this stuff now :o
User avatar
scifipirate
 
Posts: 29
Joined: Fri Nov 02, 2007 10:18 am

by scifipirate on Sun Nov 04, 2007 11:36 pm

4 and 5 aren't giving me the green now and the springs on the batteries are getting really hot

7 to 5 i get nothin


8 to 6 nothin

this device is crazy
User avatar
scifipirate
 
Posts: 29
Joined: Fri Nov 02, 2007 10:18 am

by scifipirate on Sun Nov 04, 2007 11:38 pm

dear god I put the AVR back in and the green LED is going through it's cycle :?: :!: :?: :?: :?: :?: :!: :?: :?: :!: :!: :!: :shock:

lemme see if the IRs are working
User avatar
scifipirate
 
Posts: 29
Joined: Fri Nov 02, 2007 10:18 am

by scifipirate on Sun Nov 04, 2007 11:41 pm

hahahaha it turns TVs off now!
User avatar
scifipirate
 
Posts: 29
Joined: Fri Nov 02, 2007 10:18 am

by montag on Mon Nov 05, 2007 2:28 am

Just a guess.

AVR was backwards? :wink: If that was the case Mitch is not kidding those are tough little ICs.
montag
 
Posts: 60
Joined: Sat Jun 16, 2007 1:43 pm

by scifipirate on Mon Nov 05, 2007 10:29 am

montag wrote:Just a guess.

AVR was backwards? :wink:


nahh
User avatar
scifipirate
 
Posts: 29
Joined: Fri Nov 02, 2007 10:18 am

by maltman23 on Mon Nov 05, 2007 7:51 pm

I'm not sure what was wrong. But I'm glad you got it working. Now, go out there and turn off TVs!

Mitch.

maltman23
 
Posts: 134
Joined: Fri Jul 13, 2007 4:54 pm
Location: San Francisco

by scifipirate on Tue Nov 06, 2007 12:01 am

yeah it'll go off and I'll wiggle the thing and it'll come back on. It's cool.
User avatar
scifipirate
 
Posts: 29
Joined: Fri Nov 02, 2007 10:18 am

Please be positive and constructive with your questions and comments.