camera power supply
 

where does the cmucam get its power from when hooked up to a serial port? I was thinking through the serial cable, but it doesn't show a positive terminal in the diagram on the serial cable. do you know where it gets power from when running the cam from the serial cable with an emulator (to install and test the firmware)? thanks for the help.
-Stephen

Re: camera power supply
 

You need to hook the CMUcam up to an unused PWM output on the RC so that it can draw power.

Re: camera power supply
 

First we hooked up a pwm cable to supply power from the RC to the camera module, but noticed that within a couple of hours of testing, the backup battery died. So we decided to just use an external power supply running at around 7V (approx voltage measured from pwm output) and connect that to the power input of the camera. We found using a power supply easier for calibration and testing of the camera since it did not drain the back up battery. But when running the actual robot you probably want to connect to the pwm output.

Re: camera power supply
 

help,
ok, I'm all ready to hook up the camera to the laptop to test the firmware, but there is a chip next to the serial port on the cam that will get bent if the cable is attatched to the serial port. has anyone had this problem? what can I do to fix this. it seems likely that the chip could have been placed in the wrong place possibly, or we could find a serial cable with a smaller end. what should I do? also, if I hook up the cam to the controller, will I have to write code to turn the current on for the pwm? also, where do I get the driver for the serial cable for the cmu_cam? thanks in advance,
Stephen

Re: camera power supply
 

Is the chip you're talking about the chip with the camera lense attached to it? We just used a standard serial cable, like the one used to program the robot and it fit fine. Are you talking about some other chip? What does it look like? Did you hook up the serial to TTL converter (small square board with 3 header pins) directly to the board? If so, try taking it out and connecting the three pins to a pwm cable and then plugging the cable back in the camera board. This should give you more room for the serial cable.

As for the power for the pwm, you don't have to write code to turn it on. The power is always there...the only thing you can change in the code is the pwm output which is the signal across the white wire. Hope this helps.

Re: camera power supply
 

1) That chip does not go on the camera board, read the manual carefully. It goes on your actual robot controller into the TTL port(Hopefully I am on the right track)
2) Go to IFIROBOTICS.COM and download the latest code for the camera. To test the camera you don't need to write code because it is provided in the default. However, you can modify it to fit your needs for the competition.

Re: camera power supply
 

thanks for the help guys, now the problem is that the thing won't even turn on still. does that chip you were talking about (which was indeed the chip I was talking about), make the camera not work unless it's attatched to the controller?

Re: camera power supply
 

No, if you are just using the JAVA GUI software on the computer you do not need to attach the little board. This is for communicating with the robot controller. By any chance, did you turn the power switch on the camera on?

All we had to do to get the camera talking to our PC was hook up the power using the pwm cable, connect the serial cable from the PC to the camera, hook up two servos to the pan and tilt output (if you want), and switch the power on.

Have you tried reading the documents in this link from the IFI robotics website?
http://www.ifirobotics.com/docs/cmuc...-software1.zip
It has a calibration how to...and a camera manual of how to set up the camera.

Re: camera power supply
 

no, I checked. it's turned on. but we're still having problems (won't even turn on led's)

Re: camera power supply
 

Make sure..
1) Both the back up battery (7.2V) and 12V are charged.
2) You have the 12V battery connected to the robot.
2) You have the back up battery connected to the robot.

If this doesn't work, I would take a volt meter and measure the voltage across the red and black pwm cable connected to your camera's power input to make sure that your camera is getting power. Also, make sure that the black wire for the power is plugged into the camera board where there is a 'B' marking.

Re: camera power supply
 

are you sure you need the 12 volt battery attatched? I read you don't, as well as another guy in my group.

Re: camera power supply
 

Hm...i'm not sure...i've read somewhere that the back up battery connects directly to the pwm ports. But we've always tried running the camera with both batteries on. Haven't tried running it off of just the back up battery.

Well, if you took a volt meter and measured the voltage across the pwm power headers and got around 7V then the camera should be fine running off of just the back up battery.

Re: camera power supply
 

Please feel free to correct me if i'm wrong, but you do not need the 12v battery to run the camra. The PWMs run from the backup battery. Like others have said this runs down the battery very very fast. Our solution to this was not to plug it up to an external power supply at the same voltage but we just switched the pwm cable connecting the camra to the robot controller to the Digital In OR the Analog In. This seemed to fix the problem with the battery running down because instead of using the backup battery it will get its power from the 12v.

Re: camera power supply
 

Yes, I agree...you shouldn't need the 12V battery for the camera. However, doesn't the analog and digital I/Os provide only 5V and GND? The pwm outputs provide about 7V. So would the 5V be enough to run the camera? I am asking this because doesn't the camera have an on board 5V regulator which needs a voltage greater than 5V in order for the camera to work?

According to the camera specs on IFI's website, the nominal operating voltage is 7.2V and the acceptable range is 5.2V to 8.6V. So I think 5V is cutting it a little close.

Re: camera power supply
 

Hi
First off, make sure your backup batt is putting out 7.2 volts - maybe even more if it's fully charged. Otherwise, make sure the plug is in the right hole and in the right direction.
More: The camera itself actually runs on 5v, which explains the regulator but the servos that it controls and provides power for need the 7.2v. you can get a hold of a 7.2v regulator if you need to run it for prolonged periods, but I personally wouldn't try to stick it into a digital IO or analog.
Follow the datasheets and recommendations.

Sparks

Re: camera power supply
 

:eek: BE CAREFUL! When we hooked up our camera yesterday, according to the instructions, we got the dreaded "puff of smoke" from the PC board. Any help? How much is a replacement? What did we do wrong?

Re: camera power supply
 

Phil,
That puff was probably your 5v regulator. We had something similar happen, where it started pulling all the current we could give it. Luckily, we had it on a modular power supply, and could vary the current, so we never blew it out, but there was a definite short between +7.2 and GND. We did all sorts of testing, and in the end, something wierd happened and it started working perfectly again.
To test yours, hook 5v (a KNOWN 5V SUPPLY CAPABLE OF REGULATING CURRENT, NOT A BATTERY!) set the current regulator to about 200 milliamps, and hook the leads up to the GND and 5V pins on the regulator. If the camera still works in this setup, it's something to do with the regulator, or maybe something before that. If it doesn't, then a chip or something blew, and you're outta luck.

Good luck!

Sparks

Re: camera power supply
 

This is in response to a previous post about not needing to have the 12V battery connected in order to run the camera off of the pwm power. Well, yesterday our team just plugged the 7.2V battery in and not the 12V. What we measured was that there was no voltage across the pwm. So I guess you do need the 12V battery in addition to the 7.2V battery to power the camera.

Re: camera power supply
 

What you need is for the RC to be running. When it shuts down, it removes power from all outputs, including the PWM power pins. The RC won't start up without a 12 volt supply, and with the 2005 firmware it won't run on backup power alone for more than a few seconds before it shuts down.

Re: camera power supply
 

I found out the same thing.

Re: camera power supply
 

why does First show the ttl adapter chip for the cmucam hooked up to the ttl serial port on the microcontroller when they are both male pins? so what's going on here? what should I hook up to what?

Re: camera power supply
 

Look closely on the TTL chip at hte IC where you plug in the PWM cable. On the sides of the IC there are small holes. You slip that part onto the RC. When I first looks at that my face was like this :yikes: or this :ahh: . So the way it works is that the PWM is connected to the TTL chip like regular, and then u place the chip on its side so it slips onto the TTL port all pretty-like. By the way, when the chip is on that port, it is extremely flimsy and can fall out pretty easily if a robot moves a lot and hits things in a competition. Will FIRST allow us to use electrical tape to tape it down since electrical tape is not allowed to be used as an adhesive?