Hello, I have a circuit that works perfectly from a breadboard, but fries every single Arduino Pro Mini after being wired together. The Pro Mini's become unresponsive, and give errors when connecting to the IDE. This is the SECOND time I tried to wire this (bunch of wires), thinking that the first time maybe I made a mistake. Well, after a much neater soldering job and meticulous transfer from the breadboard, I still end up with dead Arduino's. I was wondering if someone could look at the picture and identify how exactly it has become the Pro Mini killer?
Picture of breadboard sketch that works flawlessly when on breadboard connected to both Pro Mini and Uno:
Picture of the murdering monstrosity that killed 4 boards! (2 this one, 2 the other one that I scrapped)
Also, where it says "Uno Pin" I mean Pro Mini Pin:
The two circuits are not the same. In the bottom picture you have A0 connected to a photo resistor which then gets connected to the Uno Vcc pin. This is not how it is wired on the Physical layout diagram which shows this connection to 5V.
BJHenry:
And you don't need to post another thread when your original one is still going.
I felt like this was a separate issue. That one was more focused on resistors and proofing a circuit. This one more on specific wiring after finding out the issue. I linked this post in the other one, if that helps. The intention wasn't to cross-post.
Grumpy_Mike:
The two circuits are not the same. In the bottom picture you have A0 connected to a photo resistor which then gets connected to the Uno Vcc pin. This is not how it is wired on the Physical layout diagram which shows this connection to 5V.
Yes this error will fry your Arduino.
First, thank you for such a quick reply. You're probably right, but I'm not seeing the difference. The blue wire (A0), my fault for producing a bad picture, is connected to the cathode of the light sensor, which goes to ground. It's not, actually connected to the positive VCC rail in the first picture. If that's what you're saying?
Edit:
My logic is, VCC supplies 5V to light sensor Anode, then travels through cathode, gets intercepted by A0 to output values, and goes to ground with all the other negative wires.
In the photo, you have a label that says ' -12V '. Just a word of help and support here ........ in electronics, -12 V will mean 12 volts below a reference level - where the reference level is very typically '0V'. So if the negative terminal of the 12V battery is connected to uno GND, then just label that negative terminal as GND, or 0V. Don't give it a '-12V' label.
Southpark:
In the photo, you have a label that says ' -12V '. Just a word of help and support here ........ in electronics, -12 V will mean 12 volts below a reference level - where the reference level is very typically '0V'. So if the negative terminal of the 12V battery is connected to uno GND, then just label that negative terminal as GND, or 0V. Don't give it a '-12V' label.
Thank you for pointing it out, I'll definitely keep that in mind for the future. Just out of curiosity, is it ever possible to theoretically have something -X Volts? Is below reference Volts even a "thing" in other, hypothetical applications?
toxicxarrow:
Thank you for pointing it out, I'll definitely keep that in mind for the future. Just out of curiosity, is it ever possible to theoretically have something -X Volts? Is below reference Volts even a "thing" in other, hypothetical applications?
It is certainly possible to arrange some DC sources to get negative voltages.
Eg. Suppose you have two DC batteries, A and B, assume both of those batteries are 1.5 volt batteries...DC. If you connect the negative terminal of battery 'A' to the positive terminal of battery 'B'............ then, that 'join' (ie. conductive wire) between those two batteries could be considered as being at '0V' -- hypothetically. So that 0V reference could then by hypothetically considered to be a 'ground'.
Here, the positive terminal of battery 'A' could be considered to be 1.5V higher than ground (0V). And the negative terminal of battery 'B' could be considered to be 1.5V below the ground level.....in other words, the negative terminal of battery 'B' would be at -1.5V (relative to ground). Keywords are dual polarity power supply.
toxicxarrow:
Is below reference Volts even a "thing" in other, hypothetical applications?
Yes it is! Ever seen a multimeter with just a single lead? Aka, you can ONLY measure across something aka reference to another point. Voltage is always relative.
You can compare it to speed. That's is relative as well as where we usually call the earth the reference aka 0km/h. And similar to voltage it can be negative although in speech we like to state the absolute speed. But in calculations it's pretty handy to be able to distinguish between "left to right" or "right to left" motion.
And indeed, if we talk about 12V or -12V we usually mean reference to some GND or 0V.
But in order to distinguish between the connectors of a (DC) power supply it's common to refer to 12V+ and 12V- aka with the sign as a suffix so not to confuse it with a voltage measured to some reference.
Also note..... in your bread-board diagram, you show a 'LDR' (light dependent resistor). But for your photo setup, there is no LDR (although, you do show an LED of some sort).
Southpark:
Also note..... in your bread-board diagram, you show a 'LDR' (light dependent resistor). But for your photo setup, there is no LDR (although, you do show an LED of some sort).
It's some kind of light sensor. One that came in the Official Arduino Starter Kit. I used the stock LDR from Tinkerkad since they didn't have one that looked like mine. I assume they both work fairly similar. Any Idea as to why my neural network of wires is ruining my boards?
septillion:
But in order to distinguish between the connectors of a (DC) power supply it's common to refer to 12V+ and 12V- aka with the sign as a suffix so not to confuse it with a voltage measured to some reference.
Suffix makes sense. So if it's relative, is there even a point to write 12V+? Is it more common to just write 12V and GND?
If you write +12V and -12V on the battery leads, that means its a 24V battery since +12 - (-12) = 24.
Either write: -, + (or V-, V+) and separately label the battery as 12V.
Or write: 0V, +12V
In other words either just indicate the polarity on the leads, or give consistent voltages measured
against the same reference (invariably ground).
I don't know how you fried those boards, but the layout with all those big loops is very susceptible
to noise, whereas the breadboard layout was necessarily tighter.
MarkT:
If you write +12V and -12V on the battery leads, that means its a 24V battery since +12 - (-12) = 24.
Either write: -, + (or V-, V+) and separately label the battery as 12V.
Or write: 0V, +12V
In other words either just indicate the polarity on the leads, or give consistent voltages measured
against the same reference (invariably ground).
I don't know how you fried those boards, but the layout with all those big loops is very susceptible
to noise, whereas the breadboard layout was necessarily tighter.
Noted about the voltage symbols. Why exactly is it bad to have noise? Can noise ruin a board? I'm sure I've seen ever messier wiring in some electrical boxes with a ton more wires.
The blue wire (A0), my fault for producing a bad picture, is connected to the cathode of the light sensor, which goes to ground. It's not, actually connected to the positive VCC rail in the first picture. If that's what you're saying?
Yes that is what I am saying.
VCC supplies 5V to light sensor
No the Vcc is at 12V as shown on your first diagram. Therefore the Vcc can NOT supply 5V to the light sensor. You are applying 12V to the light sensor and therefore frying your controller.
Grumpy_Mike:
Yes that is what I am saying.
No the Vcc is at 12V as shown on your first diagram. Therefore the Vcc can NOT supply 5V to the light sensor. You are applying 12V to the light sensor and therefore frying your controller.
First off, I thought VCC was a regulated 5V supply just like the one on the Uno. This throws me off because I connected it exactly like this on breadboard, and it worked perfectly. Are you saying that the following picture is different than the ones above?? In that case, how could it work then but not now?
Pic when it worked on the breadboard:
Edit: Blue wire still goes to A0.
I thought VCC was a regulated 5V supply just like the one on the Uno.
No you are wrong on that. On a Uno the Vcc is the input to the 5V regulator and is likely to be over 7V. On the Mini Vcc is the output of the regulator that can be either 3V3 or 5V depending on what type of board you have.
This throws me off because I connected it exactly like this on breadboard, and it worked perfectly
When it worked were you using a Uno?
What voltage does your Mini work from?
toxicxarrow:
Suffix makes sense. So if it's relative, is there even a point to write 12V+? Is it more common to just write 12V and GND?
Thing is, GND is an agreed reference point but besides that it has no physical meaning. In simple circuits it's common to make GND lowest possible point (like Arduino with GND and +5V) or the middle (opamp circuits for example with -15V, GND and +15V). But you don't need to do that, you can assign it to anything and reference it to that. So the Arduino can be powered from GND and -5V as well if you connect the GND to Vcc. Confusing because they already labeled something GND but possible.
Same goes for a supply. If the supply isn't reference to anything you usually just state the absolute value (like with speed). But if you connect the 12V+ terminal to GND the 12V- terminal becomes -12V referenced to GND aka a negative supply.
And yeah, you can also just call it the V+ terminal of the 12V supply but if all supplies are single rail with different voltages it's just easy to talk about 12V+ and 12V-. r with multiple supplies, use the supply reference and a suffix like U2+ and U2- for the terminals of supply U2. But keep in mind, there is not really a single standard and yes, that is a bit confusing. Only only the bottom line is that calling something -12V while there is no -12V referenced to GND is extra confusing.
Grumpy_Mike:
No you are wrong on that. On a Uno the Vcc is the input to the 5V regulator and is likely to be over 7V. On the Mini Vcc is the output of the regulator that can be either 3V3 or 5V depending on what type of board you have.
When it worked were you using a Uno?
What voltage does your Mini work from?
Sorry if it wasn't clear, but my program didn't have the Pro Mini schematic, so I just wanted you to treat the Uno as a Pro Mini. Replacing 5V from the picture as VCC, and Vin from the picture as RAW. On the breadboard, it worked both on an Uno (unrelated) and a Pro Mini, which is Atmega328P, 5V, 16MHz. That same Pro Mini got fried after soldering everything into the jumble of wires and hooking it up. This leads me to believe that the wiring in the second pic. is somehow messed up from the first, which caused a short circuit and fried the board?
Aka, you can ONLY measure across something aka reference to another point. Voltage is always relative.