in DM2009-PERFORMANCE & INTERACTION (TUT), MediaMobPerf, Process, Research

MicroPerf 3 – GPS Texting

GPS Texting is a flash mob done by Yixue, Ashley and Daryl. It involves 5 performers receiving visual cues from their phones to form a gigantic “WE ♡ SG” using ropes laid on the ground. This was done at an open field near Geylang Industrial Estate.

Bird’s eye view of performance site

The initial idea was for each performer to access a web app (that is made using glitch and mapbox) that shows a map, their current location, and letter which they are supposed to “draw”. Each performer would utilise the GPS function on their phone to guide them on which direction to go and how long each side of the string will be.

Site 1 & 2 shown in Mapbox software


Webapp made to coordinate movement

However, on the day of performance, the chosen site was really muddy and wet, (making it very hard to walk). The GPS was also not accurate enough, perhaps due to reduced letter sizes(insufficient rope) and cloud cover. Furthermore, half of our performers were kids (Yixue’s nephews and niece), so we decided to improvise.

Test-run with new setup

The final flash mob performance consist of 5 performers, forming a letter each. There is also another conductor who is positioned at a higher level to guide the performers below by streaming a real-time video from above so that the performers below could check on their phones if their letters are placed correctly. Each performer would first form the letter on their own, then adjust accordingly with the help of the video stream.

Final Result



With the idea in hand, a webapp was quickly prototyped to assess the feasibility of using GPS for such a purpose. The GPS is usable at large distances, therefore a suitable scale was required for the whole thing to work. The initial scales of letters required on average 60-70m of rope per letter. However, insufficient rope resulted in an attempt to tweak the letter sizes, which proved to be a bad decision.

Left: Glitch was instrumental in making a functional app with minimal fuss.
Right: Measuring tool for estimating distances.

The original plan was to have the performers open the same app on their phones. The app is synced; so the map will show the performer the next point to move towards relative to their current location.

Instructions for performers

For performers to visualise…

Materials and Tech

  • 5 reels of 55m white rope
  • Mobile phones
  • Glitch platform (nodejs app)
  • Firebase Realtime database (for synchronization)
  • Geolocation Api
  • Mapbox