New Arduino Uno Mini Issue

[peteh1980]

Hi Arduino community I need some help as a noob please

I have purchased the starter kit with the standard Uno included and have a basic understanding of the code etc.

I want to use Arduino to control a series of LED's for a 1/8 scale car I am building. I want to control the lights from my phone using a custom app from MIT App Inventor 2. Due to the limited space in the car for a board I have purchased the Arduino Uno Mini, I have spent a week trying to get the guide to work (Arduino, HM-10 and App Inventor 2 | Martyn Currey) I have a HC-05 bluetooth module

I was getting close to giving up when I had the idea to use the same set up/ code etc. using the much larger standard Uno; it worked!!!

Does anyone know why the Uno Mini doesn't work using exactly the same set up?? it is tiny, does it have limited features?

Any help will be highly appreciated as I need to somehow get the smaller board to work as the standard board is too big to fit in the car

Thanks

Pete

[UKHeliBob]

Welcome to the forum

When you say "Uno Mini" do you mean the limited edition board or something else ?

[anon73444976]

@peteh1980

get the smaller board to work as the standard board is too big to fit in the car

A Nano would be a better size factor, I think, or a Mini/Pro Mini.

[peteh1980]

Hi, thanks for your reply

Yes its the Limited Edition Uno Mini, I'm really confused why it wont work when mirroring the set up of the Uno that is working

[sterretje]

@peteh1980, your topic has been moved to a more suitable location on the forum. Installation and Troubleshooting is not for problems with (nor for advise on) your project See About the IDE 1.x category.

@peteh1980

I have spent a week trying to get the guide to work (Arduino, HM-10 and App Inventor 2 | Martyn Currey) I have a HC-05 bluetooth module

Which problems are you experiencing?

[alto777]

@peteh1980

Yes its the Limited Edition Uno Mini,

Besides the missing and not-missed barrel jack, the differences are minimal and insignificant, or appear to be.

Please post the entire sketch that works on an UNO and doesn't work on the LE version.

The LE is so cute, I can't bring myself to actually use it and my GF refuses to accept a gift of earrings, well OK a bit heavy for earrings, but…

I do want to know if there is some difference that might be good to find and remember.

TIA

a7

[peteh1980]

Haha, it is small

I'm using this:

char Incoming_value = 0;

void setup()
{
Serial.begin(9600);
pinMode(13, OUTPUT);
}

void loop()
{
if(Serial.available() > 0)
{
Incoming_value = Serial.read();
Serial.print(Incoming_value);
Serial.print("\n");
if(Incoming_value == '1')
digitalWrite(13, HIGH);
else if(Incoming_value == '0')
digitalWrite(13, LOW);
}
}

Very simple, just to control 1 LED via MIT app inventor 2 as a start

[UKHeliBob]

@peteh1980

I'm using this:

Please follow the advice given in the link below when posting code, in particular the section entitled 'Posting code and common code problems'

Use code tags (the </> icon above the compose window) to make it easier to read and copy for examination

How to get the best out of this forum

See also FAQ - Arduino Forum for general rules on forum behaviour and etiquette. Hello, Welcome to the Arduino Forum. This guide explains how to get the best out of this forum. Please read and follow the instructions below. Being new here you might think this is having rules for the sake of rules, but that is not the case. If you don’t follow the guidelines all that happens is there is a long exchange of posts while we try to get you to tell us what we need in order to help you, which is fru…

[alto777]

@peteh1980

Very simple…

Indeed. There is nothing that shouldn't work on either board.

How are you supplying power in each case?

a7

[octopirate]

Just for the sheer fun of it, try it with software serial.

(Clutch all available straws)

[bluejets]

Is this correct.....?

if(Incoming_value == '1')
digitalWrite(13, HIGH);
else if(Incoming_value == '0')
digitalWrite(13, LOW);

[alto777]

@peteh1980: I put this, your code,

char Incoming_value = 0;

void setup()
{
  Serial.begin(9600);
  pinMode(13, OUTPUT);
}

void loop()
{
  if (Serial.available() > 0)
  {
    Incoming_value = Serial.read();
    Serial.print(Incoming_value);
    Serial.print("\n");
    if (Incoming_value == '1')
      digitalWrite(13, HIGH);
    else if (Incoming_value == '0')
      digitalWrite(13, LOW);
  }
}

on a UNO LE mini. Selected board type UNO in the IDE, the board self-identifies as "Arduino UNO Mini" and…

it did not work. Not until I fixed the baud rate in the serial monitor, that is.

The program does exactly what it appears to be trying to do. Any '0's in the serial input turn off the build-in LED, any '1's turn it off.

That's jsut the UNO LE on the end of a USB to USB-C cable.

HTH

a7

[peteh1980]

I'm using the 5v power supply from the Arduino along with ground

I'm then using the tx and rx pins to communicate with Bluetooth unit HC-05

[peteh1980]

Hi, apologies I'm new to this so please excuse my confusion

Are you saying you have been able to get it to work? When i click serial moitor its selected at 9600, ive tried changing the board within the Ardino IDE to just Uno instead of Uno mini and still nothing

When i swop over to the standard Uno it works perfectly

I really appreciate your help

[alto777]

@peteh1980

Are you saying you have been able to get it to work?

TBC, I have just the UNO LE on the USB cable direct to the desktop machine. No other hardware.

Can you try that? With both boards? The nude boards should work identically.

Then, for the real setup you are aiming for, please clarify: how are you powering the UNO, how are you powering the HC-05 and how are the two connected? If there is a difference, say for both UNO types you using.

That has to be where you are misstepping.

And say again that literally changing out one UNO type for another without any differences to the wiring or power moves it from works to doesn't.

Any other details, feel free to add or remind us of.

a7

[peteh1980]

Hi a7

Thanks again for helping me with this

Based on your advice I have gone back to very basic circuits with this to attempt to identify the problem

As I said I have only had the Arduino starter pack for a week and learnt the basic principles using the standard Arduino board it comes with.

This morning I have used a basic circuit using both boards (standard Uno and Uno LE) the LE works fine powering LEDs on a breadboard with a manual switch no problem at all

I then searched online for a basic way of controlling 1 LED with the HC-05 bluetooth module see link below

https://create.arduino.cc/projecthub/syedmahamood/controlling-led-using-hc-05-bluetooth-module-1761ee

This worked perfectly when using the standard Uno, the Uno LE however again still will not control the LED. I get as far as pairing my phone successfully to it but it wont control the LED

I'm about as far from an expert as I can be but is seems as though the Uno LE wont communicate with the HC-05 via the RX, TX pins?? as the HC-05 is quite an old module and the Uno LE is brand new is there a compatibility issue there? the original Uno itself I believe is quite old

Hopefully you can see the picture I have uploaded, I have both boards setup with a HC-05, the jumper wires (ignore the colours please) are plugged in correctly as I have checked this numerous times. Just to clarify both boards were independently uploaded with the required code with the TX, RX wires unplugged during the upload, plugged in afterwards. I only have 1 USB port on my laptop, this is used to power the boards so I am only using 1 at a time. I found this setup easiest to compare the 2. I also ensured I unpaired the HC-05 after use, once testing the next board I repaired to the other HC-05

Hope this makes sense, I'm tempted to send the UNO LE back and buy a Nano or something small/ similar to fit in my car but I hate to be beaten!!!

[alto777]

@peteh1980

HC-05 is quite an old module and the Uno LE is brand new is there a compatibility issue there? the original Uno itself I believe is quite old

The standard being used is way older, I do not think this is your problem.

And at this point, I am tapped out - I never use i/o pins 0 and 1, they are used for the USB serial monitor, handy during development, when I usually leave the Arduino conected to the big rig so I can see what is going on.

If I need a serial port, I use another UART (on the Mega there are several more) or SoftwareSerial on the UNO.

With which, TBH, I have been less than happy. SoftwareSerial works in a pinch, but there is nothing like a real UART.

I do not yet understand why you are "getting away" with using 0 and 1 with the UNO and not succeeding with the UNO LE.

A simple experiment is worth trying: supply power to your UNO (UNO LE) and HC-05 directly, and perform your tests with the UNO you are looking at not connected over USB. Just a standalone litlte system of UNO/HC-05

There may be a difference in how the USB stuff gets out of the way to allow your own use of 0 and 1 to be uninfluenced.

I don't think so, but that's the easiest thing to try and we might all learn something.

a7

[peteh1980]

You are a genius! I still have a mains switching adaptor that puts out 5v. I wired it to that and it works!!!

Thanks a lot, very much appreciated!!

[alto777]

@peteh1980

Thanks a lot, very much appreciated!!

Happy to help. It leaves a question about the difference between the two Arduino boards. I'll have to run that to ground. One day.

If you do need or want to use the serial monitor during the development period, you could try SoftwareSerial on some other i/o pins.

If the HC-05 is only 9600 it should work well enough.

OTOH it would be a distraction the value of which only you can determine.

As I have said, I'd rather just throw a Mega at something that needs a UART.

Can't help linking to these:

https://www.ebay.com/itm/255053603705

I got 3 for ~30$, shop around.

a7

[peteh1980]

Thanks again a7

Yeah I cant help but think there may not be enough pins on the Uno LE, will all the pins be able to power LED's?

The Mega boards link you sent look awesome, loads of pins!! if you look at the pics I have attached the Uno LE is very similar in size to the board the car comes with, I'm nowhere near fitting it yet but think a Mega Mini maybe slightly too big

My next post on the forum is going to be about help writing the code to power what I need the board to do:

Leds required:

• Headlights (can be powered from 1 pin) if possible I'd like an option to flash as well as constant
• Spotlights
• Indicator/ side repeaters, these need to be able to flash the front and rear near side, another button for front and near off side. I'd also like an option to have all 4 flash at once like hazard lights
• Rear lamps
• Brake lights
• Interior/ door lights
• Dash lights, there maybe multiple micro led's in different colours (I'll know more when I get to it

There may be more that's all I can think of for now, the car comes with a speaker and engine noises that I may leave as its childish!

Do you think the Uno LE can accommodate all this?

Thanks again

Pete