After seeing how much fun you guys are having with your ArduRovers, I've decided to start a build of my own. I currently have the following equipment on order to be put into a Traxxas E-Maxx non brushless model.
3DR GPS uBlox LEA-6
3DR Radio Telemetry Kit - 915 Mhz
APM MinimOSD Rev. 1.1
Minds-I Autonomous upgrade module for collision avoidance ( will be testing other solutions as well).
I also purchased a custom roll cage to protect the electronics and need some advice on the following:
FPV goggles with head tracking
CCD camera with pan and tilt base
Video transmitter and receiver
For my video, I need to know what frequency I should use. I know that I should be using 900mhz for best penetration on the ground but since my 3DR telemetry unit is already using 915 Mhz, what are my options for video frequency?
I appreciate any input and comments.
I will post pics as I go along
I've been busy over the past few weeks working on my 4 wheel steering controller for my rover. It's based on an Arduino Pro Mini and has the ability to take a single steering input and mix it to 3 output channels. I have one channel controlling my front servo and the other two channels controlling my two rear servos. I can reverse the direction of the rear servos as well as control their steering angle relative to the front steering input. I have also added the capability to vary the rear steering input based on the percentage of throttle input so that the rear wheels only steer the vehicle at slow speed but lock into center at higher speeds. The two potentiometers allow me to adjust the rear steering angle as well as the throttle percentage where the rear servos will no longer steer.
I plan on adding functionality to read Mavlink data so that I can vary the rear steering input based on actual speed data rather than just throttle percentage.
I'm trying to setup my rover so that the sonars will detect and avoid hitting a 4" curb but I can't seem to get it quite right. Is it better to have the sensors mounted lower and aimed upwards? I currently have them sitting higher on the frame and have been experimenting with lowering the angle but I seems to be getting false triggers when they are aimed too low.
Any suggestions would be appreciated.
great looking rover, congratulations... i am working on a similar project and planning to use HC-SR04 ultrasonic sensors for object avoidance... is it possible to incorporate with apm2,5? couldnt find any support on mission planner...
Sonar testing is going well so far. The rover successfully avoids objects and I'm just trying to tweak the sensor angle so that it will detect street curbs. My current sonar angle is a bit too high so the rover is running into curbs but will detect trees and other large objects. I currently have the detection set for 300cm traveling at 1.5 m/s (taking is slow to start...lol).
Any tips on sonar setup and alignment would be greatly appreciated.
Thanks Tom C. for all your help.
I spent most of the day building a simple pan and tilt camera mount which works great. I use the rudder to control the pan and a knob to control the tilt.
I also installed 2 sonar sensors and tested them successfully in the mission planner. I'm going to give them a test run outside tomorrow.
I had to move my GPS to the front of the rover to avoid interference from the 1.3ghz video transmitter. I also ordered a pair of Maxbotix MB 1240 sonar sensors so that I can try out the APM built in collision avoidance code.
Here's a pic with the body and roll cage installed.
It's been a busy evening. I managed to get the audio and video working nicely along with the OSD. Going to tweak the OSD data that I want displayed tomorrow.
I'm amazed at how easy it is to drive this thing using FPV. I've even been able to maneuver around tight obstacles indoor :-)
More to come.....
The initial speed and waypoint direction changes are also very smooth. I reduced the gearing of the e-Maxx to a 12 tooth pinion and I was also able to set the brushed ESC into training mode which reduced the power by 50%. The combination allows for very smooth acceleration by the APM.
Until I sort out the rear wheel steering, I setup the rover for just front wheel steering and did my first successful auto run with 3 waypoints. The accuracy is very sporadic so I will be installing the external compass today as well.
I get up to 10 sats locked with the GPS with an hdop of as low as 1.63.
Photo 2013-05-17 1 56 05 PM.jpg
I'm currently planning the layout of the electronics and have a question about 4 wheel steering setup. I'm currenly using 4 channels from my spectrum receiver, one to each servo, and have setup some mixing in the DX-8 radio to achieve the steering of all the wheels.
Will I be able to do the same mixing within the APM and also the Minds-I collision avoidance system once installed or will need to use y adapters for the front and rear servos?