Author Topic: Bit of a noob, needing project assistance.  (Read 5035 times)

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Offline rstofer

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Re: Bit of a noob, needing project assistance.
« Reply #25 on: November 19, 2018, 02:31:44 am »
I think I pointed out a more rational approach above.  Try a Blinky, then try a Blinky on every pin, one at a time (Ian.M), prove that the Nano does something.

It certainly should not get warm to the touch.
 

Offline starhawkTopic starter

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Re: Bit of a noob, needing project assistance.
« Reply #26 on: November 19, 2018, 02:32:52 am »
The Nano that's getting hot is the one currently wired up. I'm prayin' it's not shot for two reasons, really -- the other being that I, er, superglued it to the keyboard case's underside...

The SD card module is identical to this one --> https://www.ebay.com/itm/172144420638
...except that I've wired it from underneath after cutting all the pins off the top because they were in the way.

The questionable Nano is soldered to a piece of perfboard on truncated pin headers. I don't think I can get it off... it should work tho, if I can get it to fit (height is a concern here). The questionable rating is due to potential static damage, it was on my drawin' desk for quite a while and I'm good at accumulating little bits of eraser rubber everyfreakingwhere.
 

Offline Ian.M

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Re: Bit of a noob, needing project assistance.
« Reply #27 on: November 19, 2018, 02:57:21 am »
If its getting hot after uploading an empty sketch (just empty setup() and loop() functions), its bad for certain.  The empty sketch will leave all pins as their defaults which is inputs, and if its still getting hot, the only way that can happen is if the '328P's internal pin driver circuit on one or more pins  has failed.

Even if it isn't getting hot running an empty sketch, you still need to test each pin you are using to determine if any are internally shorted to Gnd or Vcc.   You could use the ArduinoMonitor utility I linked to + its sketch to check them in situ with minimal disconnecting of stuff, just don't try to make an input in in your circuit an output using ArduinoMonitor, unless you have first disconnected it.

The SD interface you linked is using 10K resistors to limit the current into the SD card pins due to the Arduino's 5V logic '1' exceeding the SD cards's permissible input voltage, so there isn't much to go wrong. Its *fugly* but  OK with most SD cards for hobby projects.   If its regulator is producing 3.3V you can risk putting a card in it and seeing if it still produces 3.3V.  However the odds are the regulator is blown.
 

Offline starhawkTopic starter

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Re: Bit of a noob, needing project assistance.
« Reply #28 on: November 19, 2018, 02:59:27 am »
Yeah, it looks like I have an ArduinHosed Nano :( Either the CH340 or the 328 itself is shot on that board. My money's actually on both... see, I use Linux, and in it, there's this terminal command to show USB devices -- lsusb, aka 'list USB'. (A lot of Linux has CLI underpinnings to it.) The Arduino isn't just not showing up in the IDE, it's not being picked up by lsusb... which basically means it's gone and gotten itself into a bucket of KFC Extra Crispy :-BROKE

Oh, and to further explain the "both" -- I'm reasonably certain that the last time I pressed the reset button on the board I could see the response via board blinky. Right now it's being ignored... which means the whole thing is one cooked goose... which makes me want to use a word, quite loudly, that you can't say on TV and which rhymes with the sound a chicken makes... ;)
 

Offline rstofer

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Re: Bit of a noob, needing project assistance.
« Reply #29 on: November 19, 2018, 03:05:47 am »
OK, the board is fried as is every component on it.  That is the likely outcome of overvoltage.

What about the USB port on the PC?  Have you unplugged the Nano and tried to connect to something else?  Maybe a thumbdrive?  There is every reason to believe the port is fried.  12V into a 5V system doesn't usually end well.  OTOH, the bridge chip may have protected the PC.  Until it is tested, there isn't much to say about the port.

I think you should check that USB port and I would most certainly not plug the defective Nano into any system I cared about.
 

Offline starhawkTopic starter

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Re: Bit of a noob, needing project assistance.
« Reply #30 on: November 19, 2018, 03:08:17 am »
My computer is fine. I was powering the Nano off of a USB lead when I programmed it.

The regulator (indeed an A1117) on the SD card board is putting out 4.03v. That's a little high, IMO, but do you think it's within allowable tolerances?

EDIT EDIT EDIT: The A1117 on the SD card board was measured at no-load levels. I *could* power the board from the 3.3v lead on the spare Nano once I bodge that in -- *but* I absolutely cannot exceed 25mA current draw. Anyone know the typical draw of an SD card? Full size, not Mini or Micro...
« Last Edit: November 19, 2018, 03:10:02 am by starhawk »
 

Offline Ian.M

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Re: Bit of a noob, needing project assistance.
« Reply #31 on: November 19, 2018, 03:21:17 am »
Nope.  3.5V would be an absolute upper limit for what's acceptable out of a 3.3V regulator.   Connect a 330R resistor between its output and Gnd to load it with 10mA, and check its outputting between 3.2V and 3.4V.  I'd bet it will fail that check as well.

IMHO its FUBARed, and you will need to either replace it or remove it and feed the SD interface 3.3V from an external source.  I'd be very suspicious of  a Nano's 3.3V pin being able to supply enough current for a SD card as its drawn from the USB interface IC, not a separate 3.3V regulator like a Uno has.
« Last Edit: November 19, 2018, 03:34:02 am by Ian.M »
 

Offline starhawkTopic starter

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Re: Bit of a noob, needing project assistance.
« Reply #32 on: November 19, 2018, 03:31:38 am »
Hmmm... I have a 3v3 regulator that I stuck... somewhere... from one of many projects that never happened... it's a switching replacement for a 7803. Let me see if I can put my paws on it.
 

Offline starhawkTopic starter

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Re: Bit of a noob, needing project assistance.
« Reply #33 on: November 19, 2018, 03:45:24 am »
Found the regulator, and the replacement Nano took its programming with absolutely zero trouble. I didn't even have to hit the reset button this time to get it to listen!

I'm gonna see if I can't go ahead and put this thing back together. So far everything's coming up Starhawk (to borrow a catchphrase) -- but my luck usually holds together like dry snow in a kid's glove, so we'll see... I'll let ya'll all know how it works out once I've (re)wired and (re)tested it all.
 

Offline Ian.M

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Re: Bit of a noob, needing project assistance.
« Reply #34 on: November 19, 2018, 03:58:04 am »
Do check the I/O pins you need for the project on the replacement Nano before you put it all back together.  Time spent confirming there was no significant ESD damage while it was knocking about on your desk will save you a lot of time and much head-scratching and swearing if you have any problems with the completed assembly.
 

Offline starhawkTopic starter

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Re: Bit of a noob, needing project assistance.
« Reply #35 on: November 19, 2018, 05:55:19 am »
It's all together... and...

Keyboard controller is whacked. All three LEDs come on and stay on. I sadly recognize this symptom...

Of course the chip is proprietary, and eBay doesn't carry keyboard controller PCBs. And, the last time I blew one up, I found out that SolidTek doesn't deal in "small parts" -- they said forget it, buy a new one.

I have another one, but it's USB, and although I'm about to check, I'm reasonably sure its PCB is different inside. These keyboards are not internally consistent. Some have a single-protocol PCB, some have a dual-protocol one, and the way the keyboard proper attaches to the controller PCB is sometimes different. Of course I can't replace it for less than $25ish... which I don't have right now  |O
 

Offline Ian.M

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Re: Bit of a noob, needing project assistance.
« Reply #36 on: November 19, 2018, 06:50:56 am »
Looks like you've screwed the pooch.   That's an unfortunate consequence of making a serious wiring mistake (and not catching it before power-up) when hacking stuff together to fit inside a difficult to replace device - yes old PS2 Keyboards are readily available, but finding the exact same one so you can swap controllers and salvage the work you've put in to modding its case is difficult and expensive.

An additional consistency issue is likely to be the layout and connections of the keyboard matrix.  Even if the the controller board looks identical, if its off a slightly different model, it may have the wrong firmware for the matrix in your keyboard and at best the key mapping will be scrambled and at worst it may damage the controller if a key shorts two scan outputs together instead of connecting  a scan output to an input as it normally should.   
 

Offline starhawkTopic starter

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Re: Bit of a noob, needing project assistance.
« Reply #37 on: November 19, 2018, 06:56:17 am »
Controller and connectors were different. Swapped both in, after fixing a little 'misfeature' and wiring it up -- keyboard uses jumper leads to select USB or PS/2 or both -- so I had to add the leads for PS/2. Easy peasy.

Now it doesn't want to work the SD card. The card is fine -- either I goofed the wiring or the extra volt being put out by my 3.3v regulator is making a difference -- or, which I vaguely remember from the last time I did this, the card absolutely has to be FAT32 formatted. (The one I'm using is so small it can only be FAT16 formatted... why use my 512mb card when I can't even fill up a 16mb one? Yes, megs, not gigs!)
 

Offline Ian.M

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Re: Bit of a noob, needing project assistance.
« Reply #38 on: November 19, 2018, 07:19:12 am »
So run a SD card test sketch, e.g. the one at https://www.arduino.cc/en/Tutorial/CardInfo
 

Offline starhawkTopic starter

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Re: Bit of a noob, needing project assistance.
« Reply #39 on: November 19, 2018, 07:40:42 am »
FAT32, strictly. Everything's working except for the keyboard now |O

I guess they didn't bother with the PS/2 firmware for the chip on this model, since it's USB. Let me re-check the PS/2 keyboard, and if I can get it working with a USB-to-PS/2 adapter I'll re-solder it in the morning. Some of my worst work was on that keyboard.
 

Offline starhawkTopic starter

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Re: Bit of a noob, needing project assistance.
« Reply #40 on: November 19, 2018, 08:38:08 am »
The old keyboard's one cooked goose. Bedtime.
 

Offline starhawkTopic starter

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Re: Bit of a noob, needing project assistance.
« Reply #41 on: November 19, 2018, 04:40:11 pm »
Found a new keyboard for dirt cheap, and Dad agreed to buy it for me. I think at this point I'm down to problems I can wrangle with :) thanks everyone for all your help, seriously.
 


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