My project was to interface the blackfin controller to the sabertooth 2x5.
The goal was to create a SRV-1 that was larger and could carry a larger payload…
The project started with the lynxmotion tri-track chassis, with a sabertooth 2x5 motor driver. I originally used a standard rc receiver to drive it around, now I have a switch to toggle between CPU and RC modes.
Getting the blackfin to talk to the sabertooth was very easy, as the blackfin comes with 4 pwm outputs. Howard over at the surveyor website had a project that was already using the pwm outputs. Once connection was made, it was fairly simple to modify the existing console code to allow things to move around.
Some future ideas I plan to add are:
Maxbotics EZ-1 sensors for object avoidance
Laser range finders for forward ranging
Onboard charge circuit (need to charge 3 different batteries)
Small gripper or hand to grab objects
Upgrading motors to higher RPM motors
Details on project:
Chassis: Lynxmotion Tri-Track chassis
CPU: Surveyor Blackfin SRV-1b board
Batteries: (1)4.8v rx pack for rc rx. (1) 9.6v tx pack for cpu. (1) 11.1v lipo for motor drive.
RC Rx: Spektrum AR6000 (newer model)
I’ve been playing around with a SRV1 camera with the base expansion module (just wanted to add wifi to it, no need for the other stuff) for about a month now, ran into all sorts of problems when I first got the thing put together, I had a bad wifi module which drove me nuts because the problem was the transmit side of the module was dead, and it was finally replaced after buying a second one. I have it mounted on a pan/tilt setup on top of a A4WD1 rover. Now with everything working I am finding “gotcha’s” with the SRV1, with the first thing being the servo control is not all that great, I had hoped to avoid using a separate servo controller, but that’s not an option. The SRV is going to just be for tracking objects and few other things. Since the wifi has 2 serial ports, I intend to use it to talk with a micro which in turn will collect sensor data. I am hoping to have it controlled via pc as well as the ability to operate on it’s own.
I only bought the Blackfin camera and WiFi. No base. Took forever to learn enough WiFi stuff and get the video over the WLAN (bought a pocket WLAN).
It’s currently mounted on top of my “MicroMoose” (too big for a Micromouse) 'bot. Probably just use the camera/Wifi for video and coms, although I also have a PS2 module and a BB2 BasicAtomPro on board. I’ll shift over to the Blackfin CPU later.
I had hoped to use the DC servo motor drivers, but they can’t handle the current for my Lynxmotion motors. Oh well. I have a RoboJaw driver for that.
The faster WiFi serial link should be nice. But aren’t they connecting both up to the Blackfin uP?
I’m putting together a ring of six SRF08 ultrasonic sensors, with a dedicated processor. Also have a TPA81 and TSL1401 Line sensor camera, and several Sharp IR sensors to mount somewhere!
I had hoped to use the blackfin for more than just the image processing, but I am going to keep it just as that, another sensor. The Matchport b/g module has 2 serial ports, the first port is used by the blackfin camera, the second serial port is not used.
The problem I am trying to resolve is this, I am using another cpu to monitor sensors and other things, so it will also send and receive information(all text, responces to color blobs and the like) from the blackfin camera, HOWEVER I will lose the ability to remotely view what the camera is seeing because you cant connect to the blackfin with more than one connection at a time. So basically I won’t see any images after I am done testing/configuring the blackfin.
I know it sounds odd because there is a second serial port on the matchport I can use, but you can’t tie it to the blackfin like one would think… SO…
and have my main cpu on the second serial port for me to send/recieve/control on, this way I can tell my cpu to switch the 74HC4052 when I tell it to, and this way I can see the video remotely if I needed to, just like as if it was the basic blackfin camera wifi setup. I’ve already gotten myself confused as hell, but I think this could work. My other problem is that I really suck at c programming…
I am using the Sabertooth 10amp controller for my motors, which my cpu will control as well. I am using the Parallax Propeller whcih I think I have gotten pretty good at programming with so hopefully I will start getting things going.
Yeah, too bad the second serial port basically can’t be used. I was thinking that the Blackfin could sometime read its 2nd serial port (?), and serve as a “router” for additional traffic (packets) to another uP.
I like your mux chip, Earlier today I proposed doing TTL muxing for the SSC-32 on another thread. This chip might be a solution there also.
I have a PS2 for early uP control of the 'bot motion, and I’ve used BlueSmirf (search this forum) for uP communications before on my other 'bots. Might think about using it here as well, if the Blackfin can’t be made to handle the traffic.
What’s nice about the blackfin w/wifi is that you can actually hookup the second serial port to say a gps(3.3v) and just grab all the data onto a pc and at the same time see video, but like I mentioned before I have run into the problem with how to configure my robot so that it’s not covered in all sorts of electronics when they are not all needed. Especially since I want to be able to manually control it or have it run autonomous.
Hopefully I will have that mux chip this week so I can get it wired up and see how it works with my setup.
yeah, I’m curious to hear how the mux works out. I too have a lot of stuff I’m putting on the 'bot. I’m doing it now, mainly so I know that there is a place to mount it.
So you HAVE been able to use the 2nd serial port while piping video back to the PC? That’s what I want! Oh yeah, it would have to be 3.3v, or a converter.
Consider using a uP to collect the sensor data, and packetize it for transmission to the main uP.
Oh yeah, the second serial port is definately useable, I know there was a debate on it for a while, and it ended up being “so how do I interface a 5v serial device to this thing” but they had asked the question the wrong way…(nothing like a 2.7k resistor or two!) The nice thing about the newer gps units are they are mostly 3.3v anyways and you can even power the gps from the blackfin expansion board(the one with the matchport WiFi on it).
