Introduction: ISS Globe- Blinks When the ISS Passes Overhead

About: Hello. My name's Arpan. At present, I'm an Aerospace engineering student. I love painting and making stuff.

Howdy! If you are interested in astronomy and always look up at the stars and not down at your feet, you'll surely know the ISS. The ISS or The International Space Station revolves around the earth around 16 times per day. Being an aerospace engineering student, I'm very keen about things like the ISS. If you're too, then I bet you'll love this project.

Meet ISS Globe - a smart lamp that can notify you whenever the ISS is passing overhead. Basically, it's a small (and cute looking) hemispherical lamp that gives a mild glow when connected to a power supply. If the ISS is passing overhead, the lamp starts blinking for about 30 seconds (you can customise the duration).

It's also very pleasant to look at when it just sits on the table like any other mood lamp. Sounds complicated to build, but nope, it's a very simple microcontroller project. No soldering, no glue gun, just a microcontroller(esp8266) and an LED for the main part. You can finish the complete build in just an hour! The video shows how it behaves, note that the blinking is just a demo. Although I have witnessed a flyby and blinking of the globe before writing this instructable.

Update: Blynk has been updated to Blynk 2.0 so this guide to set up Blynk and IFTTT will not work anymore. Check out the updated version of the project here:Space Station Overhead Indicator


NodeMcu WiFi development board



Female- Female jumpers (optional)

Cellophane tape


Besides these, you'll have to install two free apps- Blynk and ifttt

Playstore link:



Appstore link:



Step 1: Build the Structure

To make the globe, I used the top portion of an old LED light. It can disperse the light very well. Popping it out of the light is simple, use a screw driver to push it out of the bottom plastic part.

To make the base of the lamp, I cut a strip from black cardboard and rolled it into a cylinder. The height of the cylinder (thickness of the strip) should be a tiny bit more than the height of the NodeMcu when it is standing on its pins. I cut a circle with diameter equal to the diameter of the top globe from the cardboard and stuck the cylinder on it with adhesive. Great! The building process is complete. Now let's move to the electronics.

Step 2: Upload the Code

The heart of the ISS globe is the NodeMcu, and we need to code it to make it work as we want it to. You can find two different versions of the code in this step. One is the blink version and the other is power saving version. Let me explain what each one does.

Blink version: When you power the NodeMcu, the led will always remain on. When the space station passes overhead, the led will start blinking for about 30 seconds. After that, it'll again glow continuously.

Power saving version: The LED will remain off even when you power up the NodeMcu. When the space station passes overhead, the led will turn on for 30 seconds and then turn off.

While the second one saves power since the led is normally off, I would suggest you to still use the first one because the globe looks very beautiful when it glows. Anyway a single led will not consume so much power that it'll alter your electricity bill. I shall do a code walkthrough at the end of the instructable. So if you're interested, you can refer it to understand the working.

After you've decided which one to use, download it and open it in the Arduino IDE. Make sure you have the blynk and node mcu libraries installed. Then, replace the part of the code saying "ssid" with your WiFi name and "password" with the WiFi password. You also need to replace the part saying "Auth" which I'll explain in the coming steps. After doing these modifications, you can upload the code to your NodeMcu.

Step 3: A Little Bit of Electronics

This step is an easy one. I'll keep it short. Connect pin D1 of the NodeMcu to D7. Connect the positive electrode of the LED to D5 and negative electrode to GND of the NodeMcu.

I sanded the top of the led to disperse the light and bent the pins in L shape. I then stuck the LED to the bottom of the NodeMcu so that it doesn't occupy much space. Now the NodeMcu can be placed upside down in the cardboard bottom we built earlier and the hemisphere can be stuck on top.

Yify! The major part of the build is done! Now the only things left are configuring the two downloaded apps. Go ahead and download them if you haven't because I shall be explaining how to configure them in the next steps with screenshots. So it'll be easier for you if you follow along.

Basically, what we are going to do is create a button on blynk that triggers a specific pin (say D1) of the Nodemcu. We then create an IFTTT applet that connects to blynk and triggers that button when the ISS passes over our location. All that the code does is blinks the LED for 30 seconds if that particular pin (D1 in this case) is triggered.

Step 4: Setup Blynk

Make sure you've signed up for blynk and logged in to the app. Create a new project and the Auth token will be mailed to you. You'll need to enter this token in the "Auth" part of the code that I was talking about earlier. In blynk, click anywhere on the black screen to see the widget box appear. In the widget box, click on "button". You'll find that a button widget has been added. Click on it and select "PIN". Select gp5 from the list and you're done!

It's worth noting that gp5 means gpio pin 5 of Arduino which mapps to pin D1 of NodeMcu. So when the button is pressed, D1 of the NodeMcu will be triggered. Anyway, we're not going to press the button, let the IFTTT app do the job.

Step 5: Setup IFTTT

Again, make sure you've signed up and logged in to the IFTTT app. Click on the 3rd tab (bottom right) and select the "+" symbol on top right. From there, click on "this" which should be in blue colour. Search "space" in the search bar and click on it. Click on "ISS passes over a specific location" and select your location.

Now click on "that" and search for "webhooks" on the search bar. Click on "make a web request" and enter the URL. Select "put" in the method section and select "application/json" in the content type. In the body, type ["1"]

I know what you're thinking, I didn't elaborate about the URL section. Well, here you go. The URL format is https://IP/Auth/update/D5 Replace Auth with the Auth token of the blynk projectand IP with blynk cloud IP of your country. To get the IP, open command prompt and type "ping". For India, the IP is

Woah, that was a lot of configuration. But good news. We're done! We've completed making the ISS tracking globe.

Step 6: Look Up at the Sky!

There you go. Your very own ISS overhead indicator is ready to roll. From now on, every time the ISS hovers over your location, the cute globe will let you know. From what I've seen so far, the ISS crosses my location once or twice most days. There are a few days when it doesn't show up at all, but that's kinda rare. Some days it even crosses three times.

Well it's always good to know there are people working up there and really feels exciting when they hover overhead. And if it's after sunset, you can even run out and have a look at it sweeping through the sky, and may be wave a hello!

Update: I have witnessed it working quite a few times till now!

Step 7: Code Walk Through

This walkthrough is for the blink version. The power saving one is almost the same if not simpler. Here's all that's going on in the loop() function (since outside it is all initializations and some other basic stuff to get the development board running)

We begin by starting blynk using

First step is to turn on the led by using digitalWrite() and setting pin D5 to HIGH

Now when the ISS passes overhead, ifttt is set to trigger gpio pin 5 i.e. D1 to HIGH and since D1 is connected to D7, D7 will read D1's state. So when D7 reads HIGH, the if() block is executed

Inside the if() block, a loop runs through setting D5 LOW then a 1 second delay and then D5 HIGH and again 1 second delay and so on fifteen times. Which means the LED will blink for 30 seconds.

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