10 votes
Accepted

Turning all LEDs on (FAST.LED)

You can use fill_solid. For example fill_solid( leds, NUM_LEDS, CRGB(50,0,200)); Or fill_solid( leds, NUM_LEDS, CRGB::Red);
6 votes
Accepted

Pin headers too long for the sensor i bought

Cut one pin off. Get some wire cutters and position them in the groove between the last and next to last pins in the row. Squeeze. One pin will pop off.
  • 103k
5 votes

How many LED Strips can we connect to an Arduino Uno? Is there a way to connect 1-3 meters worth without needing extra parts (relays)?

Yes, the current draw is the main factor here. That's not really an Arduino issue though, as I will enlighten you about later on when I talk power supplies. I assume, since you don't mention what ...
  • 103k
5 votes
Accepted

Why is my Adafruit motor shield not spinning my motors?

A couple of things I see... 1.) Your motor leads may be shorting out of the housing of the motor. make sure they are not. 2.) You may have the motor on the wrong port for the given code: On line 7 ...
5 votes
Accepted

Adafruit Neopixel Library- only the first 16 LEDs respond

When something works, but not completely, it's often due to power issues. Embedded things, microcontrollers/Arduino are fairly robust and "logical". Hence, if your Arduino program works today, it'll ...
  • 2,696
5 votes
Accepted

How to measure resistance of TFT Touchscreen

As pointed out in other answers and comments, step one was trying to get a datasheet for this component. I couldn't find a datasheet for the shield, but here is the link from the vendor I bought it ...
5 votes
Accepted

Schematic for the adafruit motor shield v2.3

Everything can be found out by reading the schematic which, incidentally, is the first hit on Google when you search for "Adafruit motor shield 2.3 schematic": What are the pin holes above and ...
  • 103k
4 votes

Can't drive long NeoPixel strips with Due or Duemilanove?

Your Duemilanove only has 1k of RAM. That's not much. Each pixel takes 3 bytes of RAM (R/G/B). So (say) 60 pixels would be 180 bytes. That's less than 1k, but there would be other uses of RAM in your ...
  • 35.4k
4 votes
Accepted

How can I reduce the size of my sketch?

The AdaFruit Trinket just doesn't have a lot of memory - 8kb, of which 3kb is used by the bootloader. The order I look for things to reduce the footprint of an Arduino program are: data (e.g. large ...
4 votes
Accepted

Streaming audio from PC to Arduino over WiFi

Well, a sort of... You can stream 64kbps MP3, get it via wifi from esp8266. Then for all the rest, forget the Arduino. You need a dedicated MP3 decoder chip (many out there, sta013 was one of the ...
  • 771
4 votes
Accepted

Reduce 5v Trinket Pro to 3.3v?

The NRF24L01+ has inputs that are 5V tolerant! So you only need to provide 3.3V on the Vcc pin of the module, which you can do by putting a voltage regulator between it, and the 5V of the Trinket. So ...
  • 11.1k
4 votes

Applause reactivity

Not really an applause detector, but I have written a sound meter program you could use as a starting point for your own project. It is available here: Arduino sound meter. It works as follows: the ...
  • 37.3k
4 votes

Why are my motors attached to an Arduino MEGA not running?

As you did not give details I assume the following: You supply the MEGA via USB or external 5-12V power supply the motors are supplied via an extra external 12V power supply with sufficiant amperage ...
4 votes

How to use capactive touch on Adafruit board in Arduino mode?

Example code for capacitive touch on Trinket M0. Note: make sure to install the Adafruit FreeTouch library. // touch - Capacitive touch demo using FreeTouch. Trinket M0 version. // Note: the pin ...
  • 141
4 votes
Accepted

What is the difference between SCLK and CLK pins?

"CLK" stands for "CLocK". "S" stands for "Serial". So "SCLK" is "Serial CLocK". You also get "SCL" (often used for I2C) and "...
  • 103k
3 votes
Accepted

error: 'CLASS' does not name a type only when creating object inside another object

I think these lines still need to be in your main sketch file (in addition to being in your custom class file): #include <Adafruit_LEDBackpack.h> #include <Adafruit_GFX.h> If I remember ...
3 votes

Why is my Adafruit motor shield not spinning my motors?

Per the comments above, and the documentation from Adafruit, a 9V battery is insufficient for use with motors as they do not provide enough current.
  • 1,089
3 votes
Accepted

Exit status 1 expected primary-expression before ']' Arduino

I wouldn't use strncmp because the UID might have zeroes in it. This looks safer: uint8_t uid[] = { 0, 0, 0, 0, 0, 0, 0 }; // Buffer to store the returned UID uint8_t uidLength; ...
  • 35.4k
3 votes

Adafruit Neopixel Library- only the first 16 LEDs respond

You don't modify the library at all. The page refers to the constructor which is the last line here: #include <Adafruit_NeoPixel.h> #define PIN 6 Adafruit_NeoPixel strip = Adafruit_NeoPixel(...
  • 35.4k
3 votes
Accepted

Why does DHT-library (and others) only allow one object instance?

There is nothing wrong with the library. It does not allow just one object instance. What is wrong is your way of using it. It, and many other libraries, specify the pin numbers and other (under ...
  • 103k
3 votes

How can I reduce the size of my sketch?

An option not already mentioned, but may be worth mentioning, would be to remove the bootloader and program the chip directly with a hardware programmer (or another Arduino). That will increase the ...
  • 103k
3 votes

How can I reduce the size of my sketch?

As already mentioned by AMADANON Inc. in his answer, you should qualify as const all the constant variables at the beginning of the program. This is probably the biggest space saver. You can gain ...
  • 37.3k
3 votes

5V Trinket only outputting 3.3V?

Unfortunately I do not have the ability to comment. What I can suggest is to look at the small 5 pin regulator and look at its markings. If the IC is marked with "QT33" then adafruit has stupidly ...
3 votes

Steppermotor+Arduino Mega+ Adafruit

I'd look for a proper stepper driver, e.g. something based on A4988 or similar. I wasted a fair amount of time on the Adafruit motor-shield 2.3 until I finally abandoned it after failing to achieve ...
3 votes

5pt font for Neopixel shield

I was having the same problem until I read the library source code. Later I found the documentation reference. The classic font cursor position is defined as the top-left corner of the character cell....
  • 31
3 votes

Arduino Shield on Breadboard

Chances are the offset headers won't allow the shield to directly plug into a breadboard. As @Majenko noted, shields have a header that is offset by 0.16" from the other headers. Since a breadboard ...
  • 1,101
3 votes
Accepted

Fingerprint sensor code won't work correctly with LCD 16x2

You have pins 2 and 3 used by both the LCD and the SoftwareSerial used for the fingerprint sensor. Use different pins for one or the other. Worth looking at the Software Serial reference to ...
  • 2,147
3 votes
Accepted

Undervoltage from solar panels

You have selected a number of things that don't go well together. It is possible to use relays or mosfets to switch between batteries, and the Arduino could be used to measure a voltage. Or you can ...
  • 3,107
3 votes
Accepted

Burning the Bootloader on Adafruit Feather 32u4

"Burn Bootloader" only works if you have a programmer connected to the device. The onboard bootloader in your Feather cannot change the fuses, even though the process may indicate it has done so. You ...
  • 6,932

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