bf_f_1st program

I am learning more every day by simply trying to play with my new toy: a Bluefruit Feather board! As I mentioned before, my brother got this little gadget for me as a Christmas present, and it has been a lot of fun to play with!

I was having a bit of trouble uploading my program to it, though, until I figured out my problem. Since this took me a while, I thought I would share it with you, so perhaps you can save a little bit of time on this issue.

TL,DR: Make sure you add your username to the dialout group, so you will have permission to use the ttyUSB0 interface.

I was attempting to upload a little program (the default beginner program, slightly tweaked to change the blink time) to the board. I had the drivers installed, I could hook to the board and pull the boards data, but I couldn’t upload the new program to it.

I kept getting an error that suggested I needed to put the device in DFU mode, but that didn’t turn out to help me. The issue was simply one of permission. My username did not have permission to use the ttyUSB0 interface. So, usermod myself into the dialout group, and after logging out and back in, I was good to go!

Here is the little program that I uploaded to the board:

void setup() {

void loop() {
digitalWrite(LED_BUILTIN, HIGH); // turn the LED on (HIGH is the voltage level)
delay(5000); // wait for a second
digitalWrite(LED_BUILTIN, LOW); // turn the LED off by making the voltage LOW
delay(1000); // wait for a second

It just causes the red led to flash for 5 seconds, turn off for 1 second, and repeat endlessly. It worked great! But, that wasn’t cool enough…. So I looked over some examples and made it fade in and out with this code:


int brightness = 0; // how bright the LED is
int fadeAmount = 5; // how many points to fade the LED by

void setup() {

void loop() {
analogWrite(LED_BUILTIN, brightness);

// change the brightness for next time through the loop:
brightness = brightness + fadeAmount;

// reverse the direction of the fading at the ends of the fade:
if (brightness <= 0 || brightness >= 255) {
fadeAmount = -fadeAmount;
// wait for 30 milliseconds to see the dimming effect

Now I have my own mini Cylon with a glowing, fading red eye saying, “By your command!” (Okay, so I may be having way too much fun with this….)

Linux – keep it simple.

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