(Continued from Part I)
So with the cameras and the screen, I was ready to test them out. The screen was easy, as it had its own AC adapter. I was able to just plug it in and it came right on, gave a nice blue screen indicating that it was set for the VGA input, and after 10-15 seconds of finding no signal, it went to sleep.
I could wake it easily by either selecting a new input (VGA->Cam 1->Cam-2->VGA cycle), or by just hitting the power button, but with no input, it just went back to sleep again.
I have a mini-HDMI->VGA adapter for my tablet, but that didn’t work to give a testable signal, so I had to go hook it up to an old XP box. The booklet manual said that the optimal resolution was 800×400, but the computer’s resolution wouldn’t go down that low. At the lowest setting though, it was pretty easy to see.
Putting it back up to some 1100×800 dpi (the computer’s regular output setting), the image was still pretty clear, but the text and icons got really small. I’ll have to play with the setting once I get the bus’ computer up and running.
But with proof positive that the screen was in good shape, I went to checking out the cameras. The little, cheap camera just had the red and black wires for power, so rigged a plug using a female four-pin power connector from an old computer fan, and hooking it up to an adapter that was meant to power a hard drive. With the VGA connected to the screen, and a button push to cycle camera 1’s input I got … a black screen.
At first I checked all my connections, then realized that if I cycled the input again to camera 2, I got a picture. One Sharpie later, I had that system all worked out, and went about trying to get a nice image I could photograph easily, but found that it wasn’t easy to get what I wanted because the picture was, indeed, mirrored (just like I knew it would be but my hands still wanted to turn it the other way).
One of the other issues that people complained about was the guidance lines. In looking at the view, I don’t see them being very intrusive. I can, however, see how they form a great fixed reference point for backing up. For this picture, the camera was at couch height, and the distance to the far wall is ~21 feet.
I hooked the other camera up to the same power source, and put it in a similar placement (just next to the first camera).
The lines are more pronounced on this camera, but they are more colorful. The back wall here looks closer, but you can see less of the walls, even though the two cameras were at the same distance.
In recognizing this, the cheaper camera has a much greater field of view, but with much more distortion. At the time, I just noted it, but in thinking about it since then, it seems that this difference will actually help me with placing the cameras on the bus.
But there was another thing to test with the more expensive camera, and that was the IR LEDs. For that, it was an easy thing, as the photosensor that turns the LEDs on doesn’t need complete darkness – even a good shadow would do it. So for that, I just held the camera up off the couch (looking at the couch), and lowered it until the LEDs kicked on.
The ‘night vision’ works fine, though the bright ‘light’ of the LEDs washes out the colors. But really, when I’m backing up at night, I think the color of the object I’m getting too close to is less important than if I can see it clearly.
So my plan is now to mount the small, cheap camera up high on the bus (there’s a bevel right above the back dome window and below the clearance lamps that should put it at a great angle), and use it as a regular rear view mirror, displayed on the screen during normal driving operation. I’ll get a nice view of what traffic is right behind the bus, and a nice wide angle on the sides. The other camera looks like it will need to be pretty close to the ground for the LEDs to have a good effect, so I’m going to play around with mounting it under or just above the back bumper. Since I can change between the two views with just a click of the cycling button on the screen, I should be able to get both a ‘big picture’ and then a more detailed view when backing in somewhere.
I’ll post again for on-the bus placement testing and installation …