Asked — Edited
Resolved Resolved by Rich!

H-Bridge And Camera Tracking

Hi all,

The earlier part of this year I was trying to get my robot to track motion with the camera. I am using h-bridges and DC motors. When I set it up back then I remember a setting in the camera config to click if using an H-bridge. I'm back to the point where I'm ready to tackle that again. After resetting up the camera and reinstalling Camera Control in ARC I cant seem to find any way for it to control an H-bridge. Has this feature been taken out? I'm not sure what version I'm running with my main project but I haven't updated this one since June or longer.


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You need to have the H-Bridge set up to a Movement Panel for the camera tracking to use the H-Bridge. Once that is done enable the options to allow movement tracking and for the camera to move the robot forwards/reverse and left/right in the camera settings.

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(note: I missed the movement tracking box with the red outline, it's just to the left of where I have highlighted)


Thanks Rich. That makes sense. I'll give it a try tomorrow.

A few more questions;

I'll be using the 4 wire Hbridge Movement Panel but there are 2 panels to choose from now. Using the camera tracking which is the best one to use, the regular or the PWM panel? I've been controlling my motor speeds through scripting so I'd think if I want to have the motor run at any other speed then 100% I'd use the PWM one.

I see the movement panels only control things attached to board 0 (the first board). Can I use scripting to trigger stuff connected to the 2nd or 3rd board when this Movement Panel operates? for example; The camera sees movement and signals the Movement Panel to turn motor 1 attached to the first board (This will moves the radar on the head to the right). I then want my torso motor attached to board 2 to wait a 1/2 second and follow the radar motor and stop when it stops.


Well, I've been working all day on trying to get the motion tracking to work. First off, Thanks Rich, your advice was right on. All I needed to do was set up a PWM movement panel. That allowed the PWM to be turned on. I did get the camera to swing the radar motor towards the direction it first detected movement.

I have the camera set up on a stationary part of the robot so I had the control set to "Track by Relative Position". After playing with the Motion Delay, Fram Check settings and the Grid I just couldn't get it to Trak me with any sense of awareness. All it did was keep turning on the motor till it got to the end of the rotation. Then if it detected motion in the other direction it would swing that way in the same manor to the end of the rotation.

I was having better luck last time I tried this with my camera (mounted inside the bubble) swinging along with the radar. However then I was getting false detections with light reflections from inside the bubble. As seen here:

So, unless I'm able to work this out I think I'll have to abandon my idea of my B9 tracking movement and turning the radar with it. Damm, and it would have been so cool.

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Dave, do not give up on your B9 tracking movement, it can be done in other ways! On my robots, I use a Thermal array sensor, this can pick up a body heat pattern (8 pixels) at up to 2 metres away. Its very small and can link to the EZ-B via the I2C bus.

Here is a TPA81 mounter in my Daleks eye

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Here the data is being sent to the master microcontroller by a ultra high speed serial link, you can see the heat pattern on the LCD displays.

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Dave, it's my understanding that you may be confusing motion tracking with movement tracking. Please hover your mouse cursor over the question marks in the software for details. I've taken a lot of time entering help in there:)

I think what you're trying to do is have the robot turn his head toward motion? Can you verify? We need to know what it is you're trying to achieve before I can help:)


Thanks for the encouragement and interest guys. I really didn't give up on the idea of tracking, just this one approach. Didn't mean to sound bummed. I'm enjoying this stuff too much to get to discouraged and give up. At the most I may put it on the back burner for a while, take a break, work on something else and try again later. However I'm not to that point yet.

@DJ , It's quite possible I'm confused. It happens a lot.:) Till you mentioned it I hadn't thought the two were different. Motion and Movement tracking sounded the same in my head. I have spent some time clicking on the "?" and found them to be a ton of help. Thanks for all the time and work you've put into them.

Keeping in mind I'm using DC motors and and H-Bridge here's what I was trying to make my robot do:

I wanted my B9 to rotate at the waist horizontally, right or left and follow someone as they walk by. If the person stops I'd like the rotation to stop. If the person moves back the way they came I'd like the rotation will follow. Kinda like in your Wall-e video when he follows the red ball around. I almost had it working like this a few months ago when I had the camera mounted inside the bubble and the camera would turn with the rotation. I decided to try mounting the camera on a stationary part of the robot and use the "Track by Relative Position" option and got the above result.

Following a person walk back and forth is my ultimate animation. Now, if that's not possible or too complicated I'd settle for him turning towards movement, stop at a specified point on the radius for a specified amount of time and move back to center.

@Tony , Thanks for the suggestion and encouragement. The sensor you suggest sounds intriguing. I love the way you've used it in your Dalek. How does it make the Dalek work? Does it follow a subject walking by or just turn towards the heat source? This may be a problem in the environment I'm planning to keep my B9 in. I plan to have him standing in my game room. I have 15 pinball machines and a couple video games in there. Each one puts out a ton of heat. Do you think that would confuse this sensor?

BTW, your workbench is way too clean and your parts bins are too well marked. ;)

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Yes, the TPA81 can be used to make a robot actually follow humans see this project

Also it could track a heat source and turn towards it, I have used the TPA81 several times now with great success. You are right that if their is high temp in your games room, then the sensitivity would drop.

If you like video game consoles then you might like one of our latest products thats really selling well over here, its called Arcadie, here is our sizzle.

The iPod version was so successful that the manufacturer we licensed it to has recently released a version for the iPad mini.

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Yep, I love the classics. These are cool little items. We have something like this over here also but by a different name I think.

As far as the TPA81. I need to give these a try. In the end I'm sure I'll have the tracking function working. I just need to find the proper way to get it working. This is what makes all this so much fun; finding the best way to make what you want actually a reality.

Your help and time is much welcomed.


United Kingdom

Dave, I keep the TPA81 in stock here, so I will put one in your parcel, they are very good for tracking body heat. I will be sending Mels parcel out Surface mail either tomorrow or the next day, so I will then have an idea of what Surface mail to the USA costs. Its great to be able to help you, in your brilliant B9 build!


United Kingdom

Hi Mel, I am glad I can be of help, I just hope that Surface mail gets to you in a reasonable time, I have read that there can be holdups sometimes at US customs. Let me know when you get the parcel.



Tony, once again I'm overwhelmed by your thoughtfulness and generosity. Thank you. I look forward to hearing from you on this matter.