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Basic Electronics » Help Please **** I can only use a 9v battrey sent by Nerdkits

February 01, 2011
by Naveen07
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Ok, this is very odd, for some reason, the only battrey I can use is the one that comes with the Nerdkit, I connect a battrey I bought and it looks like I get the bars in program mode and when I run make it fails, cannot communicate to the chip, unconnect the battrey and put the Nerdkits one back and it works fine. Same thing in non-program mode, is this a common thing...Help please.

February 01, 2011
by Rick_S
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Maybe you got a bum battery. I'd try another, there isn't anything special about the NK battery. The results you are seeing is what you get when the battery is low.

Rick

February 01, 2011
by Naveen07
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Yeah, went down that as well, two pack both bad...I guess it's possiable.

February 01, 2011
by Naveen07
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OK, if anybody has any ideas, this is crazy...just got a bunch of 9V batteries and it still will not work unless it's the battery that came with the kit...not sure whats up, thanks in advance.

February 01, 2011
by hevans
(NerdKits Staff)

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Hi Naveen07,

I promise you there is nothing at all special in the battery the pack with the NerdKit, so there has to be something else that is causing this behavior. Is there anything else you are changing when you change the battery? Could you include post some good close up pictures of your setup, perhaps we can spot something strange going on.

Humberto

February 01, 2011
by Naveen07
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Humberto, thanks for getting on and replying...but I got to a point that it just did not make sense, so I am breking it all down and starting over. I will figure it out, thanks again and once I build it back up, I will post pictures if I don't get it working, either way I really feel this is a "U-S-E-R-E-R-R-O-R", I will get it. Thanks for the help, atleast I now it's not been seen out there.

February 01, 2011
by Ralphxyz
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Were you using the same battery connector on both batteries?

Ralph

February 01, 2011
by Naveen07
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Alt Text Alt Text Alt Text Alt Text I am not sure at this point, I am worndering if I fired my MCU...got a error when trying to upload a program...Led_blink said it could not read lfuse...not sure what that is, any ideas let me know.

February 01, 2011
by Naveen07
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http://img199.imageshack.us/i/dsc0533g.jpg/ http://img64.imageshack.us/i/dsc0534e.jpg/ http://img251.imageshack.us/i/dsc0535u.jpg/ http://img87.imageshack.us/i/dsc0536m.jpg/

Could not get the image thing to work so I posted the link to them on imageshack.

February 02, 2011
by Rick_S
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February 02, 2011
by Rick_S
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It's really hard to tell from your photot's but the LCD wiring appears to be WAAAY messed up. It looks like you have wires on every spot of the LCD connector. Without the backlight, there should be 6 unused connections on the LCD.

When looking at the face of the LCD, with the connector at the top edge, the pins would be 1 thru 16 from left to right. Look at the photo's closely in your NK guide. In case you need a little more clarification, here is the basic LCD wiring W/O backlight connection.

Pin#        Connection
----        ----------
1    -------  Ground
2    -------  Vcc (+5v)
3    -------  Contrast resistor (Breadboard Row 27)
4    -------  Micro pin - 13 (Breadboard Row 23)
5    -------  Ground
6    -------  Micro pin - 12 (Breadboard Row 22)
7    -------  N/C
8    -------  N/C
9    -------  N/C
10   -------  N/C
11   -------  Micro pin - 4  (Breadboard Row 14)
12   -------  Micro Pin - 5  (Breadboard Row 15)
13   -------  Micro Pin - 6  (Breadboard Row 16)
14   -------  Micro Pin - 11 (Breadboard Row 22)
15   -------  N/C
16   -------  N/C

Rick

February 02, 2011
by Naveen07
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Alt Text

February 02, 2011
by Naveen07
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dsc0537c.jpg dsc0538n.jpg dsc0539rb.jpg dsc0540.jpg

February 02, 2011
by Naveen07
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Rick, the pictures of the LCD were not that great, but take a look at these, I believe I have it wired correctly, but would love to know your thoughts, thank you.

February 02, 2011
by Rick_S
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Yep, I agree after seeing those photo's it does look correct. What are the alligator clips in the earlier photo's attached to? Your battery clip or another form of power?

Rick

February 02, 2011
by JKITSON
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It looks like the program switch is connedted to the positive (+) rail. It should be connedted to the negative (-) rail I think..

Jim

February 02, 2011
by Rick_S
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Good catch Jim. I missed that one. That would keep it from going into program mode at all now. Naveen07, make the wiring correction Jim caught and see if that allows you to again program the chip. Also, unless you wired power incorrectly to the wrong place on the micro, it is most likely fine.

Rick

February 02, 2011
by Rick_S
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Although looking at it again, that may just be a fray of the insulator. The top four photo's look more like it's going to ground... IDK??

February 02, 2011
by Naveen07
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Rick, your on the money, it is the fray of the insulator, its connected to the (-)rail.

February 02, 2011
by Naveen07
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So I connected the battery back to my setup, put the MCU in Program mode and ran make in the Led_blink directory, this is what I get.

maken.jpg

Then, I put the battery back in that came from Nerdkits, mind you its low on power, but I get a significantly better result, it gets to the point of clearing memory and can't get the chip to respond to the command.

makewithnerdkitsb.jpg

February 02, 2011
by hevans
(NerdKits Staff)

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Hi Naveen07,

Do you happen to have a multimeter around. I now suspect all your batteries of being low on power (as unlikely as that may be).

One thing you could do is follow the instructions in Appendix B on using USB Power to power the chip. Be careful with it as it does involve putting your comptuers power supply in the loop, but it will eliminate dying batteries as a possible problem.

Humberto

February 02, 2011
by Naveen07
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Will do Humberto, also I am going to order a chip and a couple of other things from you guys, thanks for the direction and I will let you know how that works out. I checked the Voltage, I was getting 8.97v close to 9, but checking the chip I get 5V, anything past the 7805 Voltage Regulator is 5v, I think this is as expected. The part I am going to try is the USB deal, let me know if the Multimeter is what your expecting, thank you. NVG

February 02, 2011
by Naveen07
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USB WORKED!!!!

February 02, 2011
by Naveen07
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Now its time to figure out why the battery wont work.

February 02, 2011
by Rick_S
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A weak battery may read close to normal with no load but once you start using power, the voltage drops below what is needed for everything to work properly.

February 03, 2011
by BobaMosfet
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Naveen07-

Attach the multi-meter to it. What does it read? Now, attach the battery to the NerdKit and check it's voltage again across the terminals of the battery--- now what does it read?

If it's good, it will fall slightly and then hold at a specific value for a little while before dropping further.

And make sure you connect the polarity properly.

BM

February 16, 2011
by devinsbusiness
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You can also use your multimeter to check the output voltage of your voltage regulator once you attach one of these questionable batteries. Maybe compare that to what the voltage is when you attach the nerdkit battery. That may give you some insight into what is going on. Devin

February 16, 2011
by amartinez
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Yes. You should see 5v from the output side. It is an amazing unit. At times past I use to use a VR but It is not very portable.

Good luck.

Al

June 26, 2011
by wintersdb
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Exactly same problem with NiMH rechargeable. Works fine with any normal (non-rechargeable) battery. Normal battery, checked with multimeter, shows 8.82v; rechargeable shows 9.68v. Across red and blue "rails," both batteries show 4.93v. But new programs will not erase microcontroller nor will existing programs run with rechargeable battery. Strange!!!

June 26, 2011
by mongo
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You might want to put a couple of bypass capacitors across the power rails. It may be picking up noise with some power sources that just won't clear out.

June 26, 2011
by Ralphxyz
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wintersdb do you have a amp meter?

You also might put a led across the rails (best to use a limiting resistor 390 -1k).

Watching the brightness might tell you that you have low ampacity on the rechargeable.

It takes current (amps) to erase the mcu not voltage (voltage is important but does not do the work).

Ralph

June 26, 2011
by wintersdb
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Thanks very much, mongo and Ralphxyz. Will try the capacitors. Unfortunately, I don't have an ammeter. Will also try the LED idea. The rechargeable is brand new and fully charged - it's comprised of 8 - 1.2v, 200mAh NiMH cells, according to the label. The MCU works fine with the USB power from my computer, but gives the same problem when USB power is run thru the voltage regulator. That makes me wonder about the voltage regulator. Thanks again for your comments!

July 03, 2011
by BobaMosfet
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Even a dead battery without load can appear good via voltage measurement. You need to test it with a load.

Use a 100K Ohm resistor alone, across the terminals of the battery in question. Can be a 1/8W resistor, which you probably have. No it won't fry. Measure the voltage drop across the resistor- if the voltage is only slightly less than the battery, it's good. If the voltage is low, the battery is bad.

BM

July 03, 2011
by BobaMosfet
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You can test your regulator this way, too.

BM

July 03, 2011
by wintersdb
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Thanks, BobaMosfet. It turns out that 8 hours of charging the NiMH battery wasn't enough to power the programming operation. 24 hours of charge did the trick though.

Parenthetically, a Radio Shack 9v Battery Eliminator (rated at 9mA) couldn't deliver enough current either. Not surprising. I've had it for years and it's pretty worthless.

Thanks again for the help.

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