31.10 - Test drive with camera
I took the Rover for a little spin today without all components 100% fitted. You can see the video under the video tab.
26.07 - GoPro on 3D gimbal.
To feed video to the transmitter I use a GoPro on a Feiyutech Mini 3D 3-axis gimbal. This gimbal can be used in an upright position and therefore makes it a perfect solution for a ground vehicle.
The gimbal is not fixed to the Rover yet as I am still deciding how I want to do it.. For this test it's just fixed with some tape.
20.07 - Modding the radio.
For controlling the Rover I got the FlySky TH9X radio from DX. This is a really nice and cheap radio with a lot of features. The only annoying thing about the radio was that it was hard to read the contents of the screen due to the lack of backlight. Luckily there was a backlight kit online that was suppose to be easy to add, so I decided to give it a go.
The backlight kit was just a little acrylic rectangle with light that was going to be mounted behind the lcd. I removed the screws of the bottom board and lifted it gently. Doing so made the lcd completely loose as it was just force fitted with the foam on the backside. The most challenging part was that the light was going to be force fitted in the same way. There was no way of fastening it and all the wires were too short to tape it or anything.
Getting both the lcd and the light positioned right was a bit of a challenge and took a few tries before it worked. The light had a Y-connector for power and was connected in the slot for the lcd, and then the lcd was connected to the Y-connector.. I really recommend this easy and cheap mod if you ever buy this radio, it makes the radio much easier to use. Check out this video for detailed instructions for this mod. https://www.youtube.com/watch?v=oZ849KW0P2g
While I was at modding the radio I wanted to add a few more things. I wanted a screen on top of the controller and wanted the power for this to come from the controller so I didn't need an extra battery. I also wanted the radio to be powered by a LiPo, and wanted to add a LiPo alarm for the battery.
I started by finding out where I could connect the power cables inside the radio so that it only got power when the radio was turned on. I then soldered wires to those pins. I ran the wire through the top of the radio and added JST connectors to them. I also wanted to power the video reciever for the monitor with the same battery so I made the connectors necessary for that.
To connect it all I opened both the monitor and the reciever and removed the wires that was included. I found out where I needed to connect the wires to get VCC, GND and VIDEO which was what I needed.
Inside the reveiver I unsoldered a jack connector and soldered the yellow video cable directly to the pin. I then run both cables out the hole where the jack connector should have been.
The yellow wire is now all that is needed to give video to the monitor. I got rid of the cable below ++.
The next step was making the connections for the LiPo battery and the alarm. I soldered the wires to the correct pins inside the radio and found a corner inside where the lipo alarm could live.
I test fitted the monitor and receiver on top of the radio to check how it would look. Everything was working fine and streaming from the GoPro.
The controller is almost done. What I need to do next is mount the monitor to the radio and the receiver to the monitor. I have printed the holder for the monitor as seen under.
07.06 - RC Radio and Mecanum drive success
So it has been a while since my last update. Haven't had much time for robots but now I finally had some time and got to sit down and test a bit more. Since the last update I have changed my homemade Uno controller with a Flysky radio.
The first challenge was to make the Arduino read the RC channels quick enough. I started using pulseIn() but it was waaay to slow. After some searching I found the rcarduino blog and started reading there. I ended up using Pin change interrupts to read the channels fast enough.
After reading all the channels I had to start figuring out how to make these values into something that the Mecanum wheels could output. I wanted the robot to move in the direction that the left joystick was in and also mix in the rotation from the right joystick. Today I finally managed to get this working thanks to this http://thinktank.wpi.edu/resources/346/ControllingMecanumDrive.pdf and some other resources online.
17.04 - Partial encoder success
It's alive!(kind of). The movement in the video is a bit slow and jumpy as I am filming with one hand and using two joysticks with the other hand.
I started working on getting remote control over the robot and using encoders to monitor and mix the different motors together. My first goal was to make it move forward, backward, turn left, turn right and then the most important one, slide left and right. (This is just the coolest thing ever.)
I made a temporary remote control with an Arduino Uno. an APC 220 RF module and two PS2 joysticks.
I then connected the other RF module to the compiter via USB and started testing Serial communication. After a bit of trial and error I found a solution that I was happy with using the library StreamSend. Which is available here http://paste.strictfp.com/39940
And after a bit more testing I connected the RF module to the Spider controller and started sending data from the remote to the robot. For encoder support I got a lot of good ideas and clarifications through Bajdi's Rover 5 code. There is still a lot of adjustments and fine tuning to get the right behaviour but this was a great step in the right direction. I will come back with more details and of course the source code when it is finished.
16.04 - Started the project
I finally got the time to restart my robot project.
This time I'm planning to finish it but I might need some help. My new plan is to make a BB shooting robot with Vex Mecanum wheels. The hardware is pretty much the same as my last try but with a few new parts. I have just started the project but will try to update this page with pictures and video as I build.
The first step was to do the same modification to the mecanum wheels as Duane Degn and CliffO. Thanks for the great tip! Was considering making some 3D printed modifications first, but really liked the simple and invisible fix you shared.