A person has already come to me asking how to interface an Axon Microcontroller to LabView. Instead of a bland answer to the effect of “It’s nothing special”, I decided to write a quick write-up about communications between computer systems; and I will use the communication between my SAGAR robot and LabView operator panel as an example.

My SAGAR project has gotten to a point where I would like to document the system design through a series of detailed posts.

First I’ll show the new interface, and talk about how it communicates with SAGAR.

In a joint effort between my girlfriend and I, SAGAR now has a super fancy LabView based graphical user interface. The video below is a screen capture of the interface as SAGAR runs a mission taking it around a parking lot. All communications are in the form of NMEA sentences. The DIYdrones ground station gave us a few ideas of what we wanted to do.

Ok, so I’m a little overexcited. I just got back from watching SAGAR complete it’s first autonomous mission. I just finished coding the navigation functions and couldn’t wait till the next day to test. Attached is an image of the mission it ran.

I used a Ardupilot program to generate the mission file with waypoints, convert it to a hex file using gcc, and I manually flash that into the Axon’s EEPROM memory. When SAGAR comes online, I give it a command to scan the mission file in memory, then I command it to run the mission.

I have been asked by a few people how SAGAR is going, so I guess I need to do some updates more often. Anyway, SAGAR was shelved for a while. The last tests of the closed loop heading controller showed I had something messing with the compass readings. Further tests concluded that my batteries were biasing my compass.

While waiting for parts to come in for SAGAR, I decided I’d kill three birds with one stone. I wanted to adapt my Irobot command code to be compatible with Webbot’s Lib, I wanted to test Webbot’s new Project designer, and I wanted to try out a Force Field Obstacle Avoidance Algorithm. This is what I came up with.

It’s an Irobot Create, controlled by an Axon 2 running Webbot’s Lib, a Sharp IR and a standard servo. Theoretically, obstacles in front of the robot will ‘repel’ it while free space ‘attracts’ it. The closer and more directly in the way an obstacle is, the more it ‘repels’ it away.

All right folks. The attached is my first attempt at writing a tutorial, so go easy. It goes over how I turned Li-Ion packs from obsolete equipment into usable packs for my SAGAR robot. For about $10 per pack, I built my own 14.4V 2.2Ah Li-ion pack, and in the attached pdf, I show you how I did it, so you can do it too.

Not all my projects are robotic in nature. This one, a simple water change system for our 40 gallon saltwater tank, is one of those non-robotic projects. For those who are unfamiliar with fish tanks, about once a week you have to change out roughly 10% of the water. The way we have been doing water changes involved two trips to the toilet with a mob bucket, and a lot of mixing of water in the shower. I decided to build a better way.

Here is a video of the LED Lab Coat with the better PWM code. If you are interested in how I programed 8 channels of software PWM, here is the source available for download.

Alright, alright. After the messages and people asking, I have decided to post my Motor-controller code. Please before you make fun, realize I am not a programmer. The code works, and I think it is a decent couple hundred of lines. Let me know what you think!!! Don’t forget to link to my site if you use/post it.