When China’s Tiangong-1 burned up last year, it left the International Space Station (ISS) as humanity’s sole outpost in space. Today six astronauts live aboard the ISS, performing spacewalks and science experiments, filming scenes for an upcoming virtual-reality series, and unloading cargo deliveries from capsules like Northrop’s Cygnus and SpaceX’s Dragon.

These brave astronauts orbit the Earth 15 times daily at 17,000mph, passing over your head 5–8 times each day. It’s fun to try to spot the ISS at night, and you can take photos of it streaking across the dark sky.

So how can you find the ISS? Sure, there are websites and apps that’ll tell you when and where to look. But you’re a maker. You want to build something cool!

Desktop ISS Pointers

The ISS pointer is a little robot arm that literally points to where the station is in space at any given time. It’s a challenge that makers approach in many ways, but the bare necessities are a microcontroller or mini computer, a stepper motor to control azimuth (horizontal motion), a servo or stepper to control elevation (altitude), and of course computer code that can figure out where to point.

Grady Hillhouse’s Desktop ISS Orbit Tracker (above ) is a robust prototype built with Actobotics parts, chain drive, and an STM32 Nucleo microcontroller board. This build lacks Wi-Fi access, so the ISS orbits are hard-coded periodically into a C++ version of the standard SGP4 satellite tracking software. Build and code shared at Instructables and Github

Patrick Ferrell’s adaptation, The Thing Pointer, uses a Raspberry Pi, belt drive, light-up 3D printed finger, and LCD display, and adds an Adafruit GPS Hat and 3-axis magnetometer so the bot always knows where it’s at and where it’s pointed: at the ISS, the planets, the moon, and more. The Python code uses the PyEphem package ( built on the SGP4 algorithms) to track the position of astronomical objects and satellites, and updates the orbital parameters from the web every couple of days. 

Developer and pentester K4YT3X built a pointer with a RaspPi and 3D-printed gears, and open sourced the code at Github; it also uses PyEphem.

Andrey (Destroyer2012) designed a totally 3D printed pointer mechanism with really cool gearing. He’s running it with an Arduino Nano, real-time-clock module, and optical endstops. It’s still a work in progress on Thingiverse.

The simplest mechanical build I’ve found is Russell Grokett’s ISS Pointer.
Using the Adafruit Huzzah ESP8266 board — he mounts the altitude servo right on the azimuth stepper’s shaft. He runs it from a Raspberry Pi (PyEphem again), and adds a 16×2 LCD display and mini speaker for sound. Build and code shared on Instructables and Github.

But by far the cutest is Don Core’s ISS Pointer Robot, using Grokett’s code. Prototyped with spare parts and Lego, it’s got an OLED display, an old hard-drive arm for a pointer, and incandescent light bulb eyes that shine when the ISS rises high enough to see. Build on Instructables.

If you’re starting your own ISS pointer project, note that PyEphem author Brandon Rhodes is replacing it with a more powerful library called Skyfield.

If you’ve got room for something bigger and splashier, ISS-Above is a fantastic project for the classroom, bedroom, or makerspace — a dedicated video tracker display that also provides astronaut’s-eye views from the ISS. The project was launched on Kickstarter by Liam Kennedy (see profile on page 27) and there are now 3,000 of these in the wild.

A Raspberry Pi calculates the space station’s position in real time and sends HD video to a TV or monitor showing when the ISS will next be present in your sky (Figure ). When the station approaches, a PiGlow LED display starts flashing and the info screen tells you where to look. When it’s overhead, the screen switches to live views of Earth from ISS (“I can see your house from here!”), maybe a Soyuz or Dragon docking, and whatever else is captured by ISS’ external cameras. It’s awesome.

Buy the basic setup for $148 (RaspPi, PiGlow, transparent case, power supply, and SD card with ISS-Above software) and provide your own monitor and HDMI cable. Or DIY it and just grab the SD card with software for $42 if you’ve already got a Pi to run it on; it’s compatible with a number of LED and LCD displays like ThingM Blink, Adafruit LCDs, and the Kano 10-LED ring. There’s an optional 3D printed bracket to mount the ISS-Above on your TV, and a teacher’s handbook for schools.

ISS Notifiers

This is an easier type of project that simply lights up or raises a flag when the ISS is in your sky — you can consult websites or apps to figure out where to look, but it’s nice just to be reminded when those astronauts are overhead.

Cat Haines built a sharp-looking, light-up, laser-cut display (Figure ) using the Electric Imp IoT platform, Adafruit Neopixels, and data fromthe website wheretheiss.at, and shared it  Instructables