Projectile Motion with Analog Computers

After some recent study of old Analog Computers HERE I thought I would try to get some feel of how to work with them using a software implementation.

I found the Open Source tool Scilab that has a module called Xcos that is a graphical editor to design hybrid dynamical systems models very similar to the  analog computer functional blocks.

I was interested in the projectile motion problem that the old Heathkit EC-1 was able to do, that is outlined in the manual on page 27. The analog Op Amps were vacuum tubes in a EC-1 !

After spending more than half of my time figuring out the software and how it worked I was able to get something close. Below is the XY plot of a projectile launched at a 80 degree angle with an initial impulse and gravity.

The diagram of the configuration is shown below.
Scilab is a very powerful tool and I have just scratched the surface of its capabilities with the use of the Xcos module. I was running this on a Ubuntu virtual machine so it was not super fast.

I would like to experience this setup on a physical analog computer since the plots are not real-time and are not on a oscilloscope like "in the day". I think I am missing the faster iterations and interactivity of the true analog system with the wiring board, meters and oscilloscope :-)

Simple ADS-B Monitoring

I tried out some Linux software tools on a x86 box with my old USB SDR dongle recently and wondered if I could do the same things with a Raspberry Pi ZeroW since the power requirements are much less than a PC or Laptop.

The SDR tools I was interested in are rtl_433 and dump1080 .

I stumbled across a web resource that was basically using dump1080 on a Raspberry Pi Zero just like I wanted. The difference was that this was a modified version of dump1080 for use with flightaware.

In the end this was a benefit since running a ground station for flightaware gives you free access to a Enterprise account on their site.

I am running this basically 24x7 now with the simple hardware below. The USB battery is constantly being charged from the line as a basic UPS. Unfortunately this USB battery drops the output when charge power is removed or inserted so it is really not a UPS (so the Pi reboots)  but since I am using a dietpi image for the Raspberry Pi, Dietpi is configured to put all the logs in memory and not on the SD card and I believe corruption is minimized. I have observed excellent uptime.

The basic recipe to get this up and running with the above hardware is to install DietPi --> HERE you can script the setup of the Wifi so it can be completely "headless" and no need to fumble with a keyboard and monitor. Then after about 30 minutes you can SSH in and run the below commands and you will be operational.

       

wget http://flightaware.com/adsb/piaware/files/packages/pool/piaware/p/piaware-support/piaware-repository_3.3.0_all.deb
sudo dpkg -i piaware-repository_3.3.0_all.deb
sudo apt-get update
sudo apt-get dist-upgrade -y
sudo apt-get install -y piaware fail2ban libio-socket-ssl-perl
sudo piaware-config allow-auto-updates yes
sudo piaware-config allow-manual-updates yes
sudo apt-get install dump1090-fa -y
sudo reboot