Laser-guided Ghost Climber using an Arduino

Almost inevitably, when I try to climb the same route I’ll forget exactly what sequence of holds they used and end up following a slightly different path. Even when I remember exactly which course to follow, I’ll still wonder whether I’m doing it as quickly as the previous climber. Yes, I know that skill in climbing isn’t all about speed, but I’m competitive like that.

That’s how I decided to make a device that could record the precise route a climber follows when climbing a wall or a rock face, then play it back in such a way that another climber could follow it while climbing and, if they felt so inclined, race against it. This concept will no doubt be familiar to anyone else who grew up playing Mario Kart’s time trial mode: it is a ghost.
Arduino Ghost Climber
In an ideal world, a ghost climber would be a 3D holographic recording of a climber that would then eerily haunt the rock face, replaying the climber’s exact body motions and speed of progress. In our less-than-ideal world, a ghost climber can be created by accurately tracing and replaying a specific climbing route using a servomotor-controlled laser turret. That’s right: in this situation a motorised laser turret is the simple solution.

Here’s the finished device in action:

My ghost climber device, nicknamed The Redpointer*, can be used in the following situations:

  • In training, for a single climber to try to beat his/her own personal best and view where on the route he/she was fastest and slowest.
  • In competitions, so that multiple climbers can race consecutively on the same route. This is considerably easier to arrange than creating two identical climbing routes side-by-side. It also has the advantage that it is portable enough to be set up outdoors on rock faces that cannot be duplicated.
  • In social climbing, to illustrate a long or complex route to a second climber without requiring the second climber to memorise it before climbing.
  • Any other scenario in which you wish to record and replay a path to be followed by a laser pointer. I’m not suggesting setting up illegal underground cat-racing circuits, but I can’t promise that someone else won’t try it…

*This is climbing humour. I’m very sorry.

Step 1: Design brief

I designed The Redpointer to have three modes:

Mode 1 – Record

In this mode, someone on the ground uses a laser pointer to trace out a path up a climbing wall.
E.g. Climber A ascends a route while Climber B stays on the ground and tracks Climber A’s progress with the laser pointer. The Redpointer then records exactly what route was followed.

Mode 2 – Playback

Here, the route recorded in Mode 1 is played back in real-time, projecting a laser point onto the climbing wall to illustrate the path of the previous climber as a “ghost”.
E.g. Climber C now turns up late to the climbing session. Climbers A, B and C all stand back and watch the laser turret replay the route Climber A took when recording in Mode 1. Climber C now knows where to climb if she wants to imitate A.

Mode 3 – Playback, record and compare

This mode is a combination of modes 1 and 2 and is designed specifically for competing against a previously set route. Once a route has been recorded in Mode 1, another climber can race against it in Mode 3 and be given live feedback saying whether he/she is ahead of or behind the pace set in the recording.
E.g. Climber C now climbs the same route as Climber A, while Climber B uses one laser pointer to track C’s progress. Meanwhile a separate laser pointer illustrates A’s ghost on the same wall so that C can tell if she is winning or losing the race. Every time C overtakes A’s ghost or is overtaken by A’s ghost, a buzzer sounds. At the end of the route, The Redpointer indicates whether A or C won the race.

Step 2: Safety issues

There are a few serious safety issues to consider before beginning this project. Please do not skip to the next step without first carefully considering these.

Rock climbing is inherently dangerous. Obviously, this danger is largely mitigated by the careful use of ropes, harnesses and other safety equipment but the danger is always present. Never go rock climbing if you are not fully competent and confident in the various techniques involved (belaying, leading, rigging, etc.).
Schematic Arduino Ghost Climber
This project involves soldering and working with electrical circuits. Always do both of these in well-ventilated, uncluttered and dry environments, using sensible precautions to avoid burns, fires and electric shocks.

Lasers are also potentially dangerous. This project only uses a pair of Class 2 lasers, about which Wikipedia says the following:

[box color=”#985D00″ bg=”#FFF8CB” font=”verdana” fontsize=”14 ” radius=”20 ” border=”#985D12″ float=”right” head=”Major Components in Project” headbg=”#FFEB70″ headcolor=”#985D00″]

  • Arduino Duemilanove board (ATmega328P)
  • USB cable
  • Two Class 2 laser pointers
  • Two 6V servomotors
  • Two 10 kilohm linear rotary potentiometers (i.e. not a logarithmic rotary potentiometer*)
  • Two 10 kilohm resistors
  • Four 150 ohm resistors
  • Three LEDs (red, green and yellow)
  • Three pushbuttons
  • Piezo buzzer from Arduino kit



For more detail: Laser-guided Ghost Climber using an Arduino

About The Author

Ibrar Ayyub

I am an experienced technical writer holding a Master's degree in computer science from BZU Multan, Pakistan University. With a background spanning various industries, particularly in home automation and engineering, I have honed my skills in crafting clear and concise content. Proficient in leveraging infographics and diagrams, I strive to simplify complex concepts for readers. My strength lies in thorough research and presenting information in a structured and logical format.

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