Posts

It has been a while since I have posted anything publicly and I think its time to bring it back! My last public post on here was 2018 where I had slowed down on a satellite tracking project. I remember having a ton of fun working on that and learning A LOT about tracking satellites using TLE data and about embedded development. Since 2018 a lot has happened in life and my career. I won’t get into that here, but I have a lot of technology experiences to share. Hopefully, on a more reasonable cadence. ...

I haven’t updated much on the satellite tracker but I figured I would make the repo public since it is just sitting there at the moment. :) https://github.com/bostrt/sattrack https://github.com/bostrt/libpredict-arduino-lib I plan to work on this some more before upcoming DEF CON 26.

Things are progressing nicely on the satellite tracker. The following is functional: libpredict modified to work on Adafruit Feather M0 Real-time clock with battery backup complete Storage for configs complete OLED display working and displaying data calculated by libpredict USB Serial interface for configuring location, callsign, TLE’s, and time (in case RTC loses battery power) Current tasks Develop a dev pcb to replace bread-board. Just something that all the breakout boards above solder onto Finish display graphics code-cleanup Screenshot & Photos Serial interface All components Polar chart that will display relative satellite position Missing photo of the satellite position data due to being in middle of display code rewrite. ...

After some fighting with libpredict, I found that I am going to need a microcontroller with better floating-point support. The Atmega series of microcontrollers do not have an FPU which means any floating-point support is hard (either inaccurate, slow, or hacked). I found that some of the ARM Cortex processors do indeed have an FPU and their also come in similar form as Arduinos or other development boards: https://www.adafruit.com/product/2772 ...

A couple months ago, I worked on putting a satellite tracking application on a Raspberry Pi. This worked okay but I have to use a keyboard to select the satellite I want to track before going outside to find it. I also have to lug around an external battery outside which isn’t fun. I could really use something more compact. Hard Requirements Screen + Buttons Tracking multiple satellites (not hundreds, just a few) Display Azimuth Display Elevation Display transponder frequency with Doppler shift Polar plot (sky plot) Button to switch between satellites Ability to set the time and timezone on device (RTC required) Soft Requirements ...