Follow ME

[sharpiemkr]

Hey Everyone...

I am currently a junior in high school with a strong passion for electronics. I am currently working on a project but I am at a stand still.

I NEED some help.

Here is the device in a nutshell:

1. Create a device that would mount on a wall and a finger like point would have the ability to follow me as I walk across the room.

2. Also, it would have a ball, it would shoot the ball to me when i push a button. So I need a sensor that would be able to know how far away I am, this way I can control the speed of the motor that shoots the ball to me.

No need to worry what the finger looks like or how the ball is shot, rather what types of sensors should I use? A sensor that can know how far away I am and a sensor that know my location in a room or outside. Do I need to wear something around my neck that would be able to communicate with my device? What is my best option? Sorry this may be a little vague.

Thanks for your help!

Tony

 

[GonzoEngineer]

What kind of ball?

Baseball?... Football?..... Ping Pong Ball?

 

[sharpiemkr]

It's going to be a racketball. Something hard enough to be put threw a launch mechanism yet easy to catch.

 

[Laplace]

I would try something like a high frequency pulse infrared emitter mounted in a cap. Then in each corner of the room mount filtered infrared sensors with each sensor having several infrared detectors at a different angle into the room. The tricky part would be getting simultaneous signal strength readings from each detector to calculate the angle of the emitter from the sensor. Somewhere from two to six detectors would be needed in each sensor. A microcontroller would probably be needed to convert those relative detector magnitudes into a source angle, and along with some trigonometry to calculate the intersection of those two sensor angles to determine the source location. Then the microcontroller could aim the launch mechanism and set the launch force for the calculated distance. I think a lot of calibration work would be necessary in order to develop the algorithm for calculating the sensor angle. This would be a good 6-month project.

 

[BobK]

Here is my idea. Don't know how practical it is but...

If you were wearing a devide that could put out ultrasonic pulse, and was synchornized by an infrared pulse, you could measure the distance to two receivers in corners of the room and this could be used to triangulate your position.

So it would work like this:

1. A controller emits and infrared pulse.
2. When the wearable device sees it, it emits an ultrasonic pulse.
3. Since the light transmission is essentially instant, the ultrasound pulse can be assumed to have started at the instant of the infrared pulse.
4. Each receiver sees the infrared pulse and starts timing until it sees the ultrasound pulse, then calculates the distance. This creates a circle for each receiver. Where they intersect is your location.

The device on you would have to be at the same height always to make this work well, so on a cap as the previous post suggested would be good.

Bob

 

[(*steve*)]

A somewhat easier solution would be to have a modulated IR transmitter on your head, and use 2 circuits similar to sun trackers used to orient solar panels towards the sun to orient the "finger" in both the X and Y axis toward your head.

It may be tricky to avoid problems from reflections, but choosing a suitable room would be a good start

If you can arrange a room with no other sources of IR then you can just look at "brightness", otherwise you'll have to look for the strength of a modulated signal. The latter provides some benefits anyway, chiefly that you can free yourself from concerns about offset voltages for the most part.