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Author Topic: Anyone know the Arduino Nano?  (Read 1114 times)

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Offline MalcolmInN

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Re: Anyone know the Arduino Nano?
« Reply #30 on: October 31, 2018, 11:09:19 AM »
large metal power transistors

 episode 4 of the Great Model Railway Challenge! 
Ah you remember the venerable 3055 as well :)
 and joy go with you, it is ok in slo-mo !

Before we redesign his cct that worked ok historically we need to find out what is wrong / different now !

If only 3v is across the track and loco, where are the other 9 (or is it 12 ? I am getting lost with the variations)  getting lost to ?
 If it is across the 2222 then it is either dead (joke !) or very hot. but maybe the volts are being lost elsewhere.  What is the Vin doing the while ? Are we on battery or beefy psu ??
What are the volts at the battery or psu doing ?



Offline Pjlons83

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Re: Anyone know the Arduino Nano?
« Reply #31 on: October 31, 2018, 11:21:33 AM »
I was just hoping to use the bits that I already had lying around. The only reason I chose the parts was because that's what I had and it's what the book told me to do! ("Arduino for dummies" seems like the perfect title for me currently!)

I've just done some googling and as suggested it looks like a higher current gain transistor may help so I've ordered some "BC517"'s which seem to fit the bill.

Sadly the loco in the original video was borrowed (and now returned) so I can't retest it but it was a much newer type.

I'm finding it a recurring theme that I set off on these journeys of discovery that seem simple at the outset only for it to be much more complicated than I ever imagined! I purchased a little PWM speed controller from ebay and that works so I know that it's possible. If I can get the NANO working then it's much smaller and I can put the board/POT wherever I want which helps with the limited space available. It also means I can set a minimum and maximum value in the code to eliminate noise and false movement at the low end before it actually starts moving.
Gold Hill - my rule 1, “just for fun” micro layout;

Clouds Hill - My first layout currently on hold;

Offline Pjlons83

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Re: Anyone know the Arduino Nano?
« Reply #32 on: October 31, 2018, 11:26:55 AM »
Sorry I replied before seeing the latest message;

We're on a 9v standard battery. I'll need to test later to answer the other questions. Its a plastic transistor case but I didnt notice it getting overly hot.

for the record I tried with a PSU set to 9v and the outcome was the same.
Gold Hill - my rule 1, “just for fun” micro layout;

Clouds Hill - My first layout currently on hold;

Offline MalcolmInN

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Re: Anyone know the Arduino Nano?
« Reply #33 on: October 31, 2018, 11:55:52 AM »
I've ordered some "BC517"'s which seem to fit the bill.
worth a punt :) I did mention Darlingtons earlier :)

Offline Pjlons83

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Re: Anyone know the Arduino Nano?
« Reply #34 on: October 31, 2018, 12:00:21 PM »
I did mention Darlingtons earlier :)

You most certainly did. Thank you again for your technical input. I was about to say that I'd be lost without the technical support of the forum members...... but actually I'm still lost with it, but somehow I get there in the end!  :goggleeyes:

 
Gold Hill - my rule 1, “just for fun” micro layout;

Clouds Hill - My first layout currently on hold;

Offline themadhippy

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Re: Anyone know the Arduino Nano?
« Reply #35 on: October 31, 2018, 01:13:36 PM »
Quick back of the fag packet calculation recons for 500ma in the worst case youll need a base current of 17ma, for a different output current the magic formulator is   full load  current / hfe ,in this case  500/30. If the ardunio is kicking out 5v and the vbe is 0.6 the base resistor  needs to be 4.4/0.017 or 260ohm. Also 17ma is getting a bit too close to the 20ma maximum pin output of the ardunio

Offline MalcolmInN

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Re: Anyone know the Arduino Nano?
« Reply #36 on: October 31, 2018, 02:00:46 PM »
so I've ordered
My problem is that I am allergic to spending money without being certain of the need (born in the north :) ) so some further testing might have been wise LOL!

Offline red_death

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Re: Anyone know the Arduino Nano?
« Reply #37 on: October 31, 2018, 02:17:46 PM »
Is the answer not much simpler - the pic that Malcolm put up of a Nano has an output of 3.3V so that is presumably what you are seeing with the Nano connected to the track?

Cheers Mike



Offline MalcolmInN

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Re: Anyone know the Arduino Nano?
« Reply #38 on: October 31, 2018, 02:18:41 PM »
If 6v is being lost in the 2222 at 500mA = 3w  the fireball should be visible over here! I think something else is going wrong, hence the need for those tests.

Offline red_death

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Re: Anyone know the Arduino Nano?
« Reply #39 on: October 31, 2018, 02:22:52 PM »
Not in the transistor, but the output voltage of the Nano on the photo you put of it (bottom right corner above pin 13 shows 3.3V output).



Offline MalcolmInN

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Re: Anyone know the Arduino Nano?
« Reply #40 on: October 31, 2018, 02:36:24 PM »
Not in the transistor, but the output voltage of the Nano on the photo you put of it (bottom right corner above pin 13 shows 3.3V output).
Ah, the probs of sequential texting ! Yes.
I was following up on Themadhippy post not yours :)

Then I was about to thank your post and say "Yes, 3.3v good spot". I did comment in my very first post "be sure it isnt a 3.3v device "

The pic I put up shows both 5 and 3.3v outputs, which I presumed to be regulated o/p for other uses. The pwm out pin is not specified on that pic (edit but it is reasonable to assume the whole board is using 3.3. NOT ! reasonable :) )

No worries, with a Hfe of 30000 odd the BC517 should sort the 3.3pwm ok IF that is the cause and not something else in the rest of his circuitry :)


« Last Edit: October 31, 2018, 05:57:41 PM by MalcolmInN »

Offline Pjlons83

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Re: Anyone know the Arduino Nano?
« Reply #41 on: October 31, 2018, 03:03:28 PM »
Is the answer not much simpler - the pic that Malcolm put up of a Nano has an output of 3.3V so that is presumably what you are seeing with the Nano connected to the track?

Cheers Mike

The images showing the multimeter reading are both the output through the Nano. It only drops when the loco is on the track. I'm connected to the Vin pin which supports 12v. As Malcolm suggests, there is a 5v or 3.3v output option which is regulated by the NANO.

So as I understand it;
Whatever you feed the NANO with  (7-12v recommended) you'll still get a steady 5v or 3.3v out of those pins. On the Uno you can input 12v on the jack plug and get 12v from the Vin pin. On the Nano there is no jack plug so the feed to the board and the track are both connected to the Vin pin.

I hope that makes sense
Gold Hill - my rule 1, “just for fun” micro layout;

Clouds Hill - My first layout currently on hold;

Offline themadhippy

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Re: Anyone know the Arduino Nano?
« Reply #42 on: October 31, 2018, 03:13:53 PM »
Quote
Is the answer not much simpler - the pic that Malcolm put up of a Nano has an output of 3.3V
only on that pin,its there to provide a 3.3v supply external circuitry that dont like 5v up it ,the rest of the outputs are standard 5v
Quote
Each of the 14 digital pins on the Nano can be used as an input or output, using pinMode(), digitalWrite(), and digitalRead() functions. They operate at 5 volts.
from https://store.arduino.cc/arduino-nano

Offline MalcolmInN

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Re: Anyone know the Arduino Nano?
« Reply #43 on: November 01, 2018, 12:33:16 AM »
The trouble with using a multimeter in this situation is that it is showing an average, not the switching state of the 2222. The fact that it is not getting hot suggests that the drive from the nano is sufficient to saturate it in the 'on' state ?? (ie. it is not analogue) . If so that means the psu (or something awol in-line) is not able to source the current needed by the motor?

I would still like to know what the voltage at Vin is doing measured wrt the 0v line. (Not from the Vin to the other track / collector as now)

But without some 'scope pics we are just guessing.
« Last Edit: November 01, 2018, 12:37:19 AM by MalcolmInN »

Offline Pjlons83

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Re: Anyone know the Arduino Nano?
« Reply #44 on: November 01, 2018, 11:57:14 AM »
I didn’t anytime to play with it last night but I’ll try and take lots of measurements tonight.
Gold Hill - my rule 1, “just for fun” micro layout;

Clouds Hill - My first layout currently on hold;

 

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