I finally put together the SoftRock Lite II kit that I picked up a while back. The kit itself was a pretty fun build, but when I was done, I couldn’t get it working with either of the laptops that I had at the time. They both had those combo headphone/mic jacks and I tried in linux and windows and I couldn’t get either to work. The only other computer in the house with an audio line in port (that was in an operable state) was my media server.
Since the last post, I have set up a raspberry pi and connected it to the arduino over usb. I configured wifi on the raspberry pi and I’ve written a simple python script to control the rover. Now, I can ssh into the raspberry pi, launch the python script and I can remotely control the rover using the same keys from the arduino sketch (‘l’ for left, ‘r’ for right, etc.
In the last post, I replaced the steering servo with a standard hobby servo. Now I should be able to control the drive and steering with an arduino. For the drive motor controller, I am using a Pololu MC33926 motor shield with a 7.2v NiMH RC battery pack hooked straight to the shield. I plugged everything in, tweaked the example code from the DualMC33926MotorShield library and it worked like a charm.
I am currently waiting on parts from China to continue working on my radio receiver, so I thought I’d start working on a robotic rover. I’ve picked up several remote controlled cars from the thrift store and I have been meaning to turn one into some kind of autonomous vehicle that can roam around the yard. Here is what I am starting with. I think I paid $1 for this truck without the controller.
After I killed my homebrew upconverter, I went back to messing around with ads-b and dump1090. The little antenna that came with the rtl-sdr dongle worked okay, but I wanted to build a better antenna to see if I could get more range. I looked online and found quite a few pages on coaxial collinear antennas and I had everything I needed to build one, so I figured I’d give it a shot.
For the next step of my homebrew direct conversion receiver is the audio amp. I used this schematic from N6QW’s Simpleceiver posts. Here is the amp mocked up on a breadboard. It worked, but not very well. There was a lot of noise and static. At this point, I thought about switching over to a LM386 based amp, but I went ahead and soldered it up on a piece of copper clad.