Lego NXT Camera

As mentioned the camera used is a small wireless NTSC transmitter. The camera requires a 9 Volt battery as a power source. The one used in this tutorial was purchased from Computer Geeks.com and cost around $40.00.

The wireless camera connected to a 9 volt battery. The camera gets mounted right before the grippers with the 9 volt battery being stowed behind the NXT processor.

As you can see from this picture we used the parts designed to be the ball holder for the TriBot to instead contain the camera. The camera holder requires lego parts to slightly overlap the front and back to ensure that the camera does not slip out. Since the lego parts do not fit the dimensions of the camera exactly the sides of the camera holder are left to slide in along the bars so that the fixture can be compressed to hold the camera tightly. The rubbery parts that the ball holder uses act as a nice buffer between the camera and the lego parts and grip the camera nicely. The white parts in the back of the holder are used to fix it to the TriBot whereas the white parts in the front of the holder slip over the front of the camera but do not obstruct the camera view. (The photo displays the camera holder from the back) The longer gray parts in the back of the holder slip over the back of the camera to hold it in place.

The battery pack is strangely the perfect size for a 9 volt battery for a tight fit. The battery holder is very basic and held on behind the NXT by a single bar slipped through the last remaining hole behind the NXT.

Here we can see the camera being slipped into its fixture from behind. Note the rubber parts grasping the camera and the sides of the surrounding box being adjusted to miss the screws on the sides.

Now the camera is in its fixture and the lower back gray parts have been lowered to hold the camera in place.

This is the final assembly of the camera and battery ready for mounting on the Tribot. You can also see the camera holder from the front with the two small bars holding the camera in place. Note that they are much shorter than the gray bars in the back to ensure that the camera's view is not obstructed.

An image of the TriBot with the touch sensor missing. The camera will go right at the end of the shorter inner gray parts which have the small black connectors on the end.

The camera has now been mounted.

A shot from the other side of the camera mount.

The battery goes behind the NXT. Slide the gray holds off from the black bar and thread it behind the NXT through the battery pack and out the other side. Put back on the gray holds to ensure that the bar does not slip out during operation.

As you can see from the picture we used the parts designed to be the ball holder for the Tribot to contain the camera and mounted it inbetween but above the grippers. The position of the camera is very important as the current placement can see straight ahead which provides the furthest field of view. The camera can also still see the surrounding area even when a ball is within the grippers. Mounting the camera lower would allow for easier ball grabbing logic BUT once the ball is within the grippers you would lose any possibility of seeing where you are going!

On the computer side connect the wireless receiver to its power supply. Connect the RCA type connector from the receiver (the yellow plug) into the digitizer. Plug the digitizer USB into your PC, wait for the installation popup and then pop in the purchased Hauppauge installation CD that came with the digitizer.

Note that the camera receiver's tuner is very touch sensitive and care should be taken before any run to adjust the tuner to the best picture quality. Even the slightest bump will change the tuner and cause the image to become unusable.

Now that we have a camera attached we can start looking for a blue ball ...