CMUcam2 code for EDU-RC?

[seanwitte]

Originally Posted by lkdjm

Both! The EDU to test, and FRC to use. I would like to know how to hook it up to the EDU. I am mainly wondering how the TTL thing gets setup. After I know how to run it on the edu I will go from there, but some of my questions pertain to the FRC as well. The schematic I want would be of the FRC. You might be right, I think I will be better off posting that in a new thread. Moderators: please don't kill me for posting kind-of the same thing in two threads.

This is from my personal experience with the code and camera on the mini-RC. There are other (and probably better) ways to do this, but I know it works. The code worked perfectly out of the box once I got the camera set up. The TTL convert has four inputs, but the mini-RC only has three pins on the TTL port. The fourth pin, which is missing, is for +5V to power the TTL converter board. I had to cut one end off of a PWM cable, solder a header pin to the red wire, and plug that into the open slot on the TTL board. Cut about 1" off of the black and white wires to give yourself some room to work. You could also use a piece of resister lead for the pin if you don't have any header pins. Heat shrink the solder joint so that no exposed metal pokes out when you plug it into the TTL converter board.

1) Connect a PWM cable from the TTL port on the mini-RC to the inputs on the TTL converter board so that the black lead matches B on the board.

2) Connect your hacked cable with the power pin to a PWM output or digital/analog input. The red pin will pull +5V from the port.

3) Connect the pin on the red cable to TTL converter board. It will be the open slot opposite the one marked B.

4) Connect a PWM cable from the TTL converter to the camera's RS232 input.

[lkdjm]

Originally Posted by seanwitte

This is from my personal experience with the code and camera on the mini-RC. There are other (and probably better) ways to do this, but I know it works. The code worked perfectly out of the box once I got the camera set up. The TTL convert has four inputs, but the mini-RC only has three pins on the TTL port. The fourth pin, which is missing, is for +5V to power the TTL converter board. I had to cut one end off of a PWM cable, solder a header pin to the red wire, and plug that into the open slot on the TTL board. Cut about 1" off of the black and white wires to give yourself some room to work. You could also use a piece of resister lead for the pin if you don't have any header pins. Heat shrink the solder joint so that no exposed metal pokes out when you plug it into the TTL converter board.

1) Connect a PWM cable from the TTL port on the mini-RC to the inputs on the TTL converter board so that the black lead matches B on the board.

2) Connect your hacked cable with the power pin to a PWM output or digital/analog input. The red pin will pull +5V from the port.

3) Connect the pin on the red cable to TTL converter board. It will be the open slot opposite the one marked B.

4) Connect a PWM cable from the TTL converter to the camera's RS232 input.

Thanks! That's exactly what I needed to know. Now I can pass that on to my electronics guy!

[amateurrobotguy]

Can't you just get rid of the converter chip altogether when using the edu-rc and just run a pwm cable from the ttl on the camera board to the ttl on the edu-rc since it has the 3 pin ttl on it and the camera board has 3 as well?

[Eldarion]

Originally Posted by amateurrobotguy

Can't you just get rid of the converter chip altogether when using the edu-rc and just run a pwm cable from the ttl on the camera board to the ttl on the edu-rc since it has the 3 pin ttl on it and the camera board has 3 as well?

I'm not sure, but I think I read somewhere that this limits the data transfer rate to 9600 baud. I have no idea why, though...

[Mark McLeod]

Originally Posted by amateurrobotguy

Can't you just get rid of the converter chip altogether when using the edu-rc and just run a pwm cable from the ttl on the camera board to the ttl on the edu-rc since it has the 3 pin ttl on it and the camera board has 3 as well?

Just to be clear, there are three serial ports on the CMUCam2 that can be used.

1. One DB9 RS232 port (the one used to hook to our PCs or the RC/EDU Program port)
2. One three-pin pwm cable RS232 port (used with our TTL-Converter chip to hook to the RC/EDU with the addition of a power line.)
3. One 4-pin pwm cable TTL level port that requires a special PWM cable to hook to the RC/EDU TTL port without the TTL-Converter chip **** Don't attempt with a normal PWM cable

You cannot hook the CMUCam2 3-pin RS232 port directly to the RC TTL port without the TTL-Converter chip so don't try it. The TTL Converter changes the signals from RS232 to TTL.

The TTL port on the CMUCam2 has 4-pins and two of the pins are in a different order than the RC expects. If you hook them up without making a special cable you can destroy something and they won't be able to talk anyway.


In general, the TTL port will be more susceptible to noise than either of the two RS232 ports as the cable to reach the RC gets longer.