Investigating Arduino #Gemma – Adapting Blink code to control 2 LEDs #STEAM

After a reader suggestion (thanks Kathleen!) I’ve also included the adapted blink code below and on my GitHub:

Getting started with Arduino #Gemma #STEAM

Getting started with Arduino #Gemma #STEAM


Tonight I found time to finally open the Arduino Gemma that arrived just before the October break.

It comes with no instructions, but Adafruit have plenty of guides on their website. However depending on where you start, you may waste a bit of time. More on that below.

The first guide I read told me nothing about how to use the Gemma, just what it was, and offered no links to follow up guides. Thanks.

The second guide I found recommended the website as a way to program the Gemma to do what I wanted. I figured that this would be a good place to start and that I could learn from other users on the site. It started quite promisingly, with a Getting Started Guide that took me through the process of installing the Chrome extension, Arduino drivers and then… well then it wouldn’t let me get any further because… the Adafruit Gemma programmers aren’t yet supported for the codebender app! There was no explanation behind the error message (what exactly ARE programmers in the context of Arduinos?) and I imagine that other beginning Arduino users like myself would have been bemused by the lack of user assistance.

Back to the adafruit website where I find some information about drivers. They confirm I have the Arduino Gemma because it’s teal not black. This is useful information and it means that my time on the Adafruit website has been wasted. I’m also still bemused at why codebender only offered Adafruit Gemma as an option earlier.

Right. Off to the Arduino website to see if they can be any more help. I now ignore all Adafruit guides in my Google search results.

I install the Arduino IDE and connect the mini USB cable to my Gemma. Red and green LEDs flicker and then there is a steady green LED.

Screen Shot 2015-11-01 at 19.20.36

I find and copy the Blink code into the Arduino IDE, following the instructions in the comments (good work, see above). However the IDE is obviously now different and “Upload using Programmer” is now in the Sketch menu. By the time I’d found the correct menu the 10 seconds of red LED blinking had passed and I had to press the reset button a few times on the Gemma to get it blinking again. Second time around the code transferred successfully.

I looked for a way to run the code, but then realised that the steady blinking red LED was the code running!

I’m off to investigate some more code now but thought I should summarise with my steps to getting the first program running on my Arduino Gemma:

  1. Download the Arduino IDE
  2. Connect the Arduino Gemma to Macbook via mini USB cable, make sure LEDs are lit
  3. (Windows users have to download drivers)

  4. Copy the Blink code into the code window on the Arduino IDE, replacing ALL text that is there
  5. Select Arduino Gemma from the Tools > Board menu
  6. Select Arduino Gemma from the Tools > Programmer
  7. Press the small button on the Gemma between the red and green LEDs. The red LED will glow dimly then begin to pulse. This means it is ready to receive data
  8. In the Arduino IDE select Sketch > Upload Using Programmer while the red LED is pulsing (you have 10 seconds to comply)
  9. Check the Arduino IDE output message. If there is an error message I suggest you repeat steps 6 and 7.

Screen Shot 2015-11-01 at 19.35.03

At this point – perhaps after a short wait – the red LED on the Gemma board should begin to blink slowly. This is confirmation of the program running!