Whenever I do a tracking jump, I find it hard to read my wrist-mounted altimeter. I thought it'd be nice to have a chest-mounted altimeter that used LEDs as a sort of progress bar to show me exactly where I currently am in the sky.Once you get to 1000' it will switch to show altitude for landing.Altimeter can been seen in use here.Operation Turn on altimeter on the ground, it will set a zero altitude, and will flash a quick white light every five seconds to tell you it is on. Everything it does after will be relative to that zero altitude.Above 1000', the lights with flash cyan every two seconds.When you are 3/4 of the way between breakoff altitude and exit altitude, the lights will go through an activation sequence. After this, the altimeter is ready to jump.On the way down, the LEDs will act like a progress bar counting down to your breakoff altitude:At 125' the altimeter will switch off. Turn it on and off again to re-zero for the next jump.Default Settings The default settings are in feet and are:Make sure these are set correctly for where you are jumping and your experience level. The variables are located near the top of the Arduino code. Change the number values to what you need.Full build instructions can be found in PDF in the Thing Files.Parts List The Arduino code running the altimeter makes use of a couple different libraries these can be downloaded from the following links: Sparkfun BMP180 Library Adafruit NeoPixel Library