Slashdot Mirror
Rear View LCD?
pctainto asks: "I'm doing some work designing a solar car for a certain unnamed university. We are contemplating installing a camera and LCD system to replace the rear view mirror, since it is hard to turn one's head in the car and it would make designing the cockpit much easier. Does anyone know of a camera/LCD system that would be relatively simple and would be able to survive for a few hours without needing a new battery? We need something with relatively high resolution, so, something like an x10 camera wouldn't work very well. (You have to be able to identify letters that are 20 cm high from a distance of 15 m)"
Do you really need to be able to identify letters in a regular rear view mirror? They look all wombly to me.
Anyway, most of the signs around here have the letters on the front.
Are you talking about installing this "intead of" your rear view mirror?
...it's more information than you'ld usually have, and if it suddenly stops working, you won't DIE.
If you replace the mirror, how will you handle a malfunction on the interstate, in rush-hour traffic??? What happens if a connection goes out, or the screen just up and dies? (LCDs just "die" more often than CRTs) You'ld want to run it off of the car battery to insure constant power, and to do this you'ld probably need to use a B&W LCD...Color is just too power-hungry and the high resolution requirement puts a huge draw on the power as well.
It sounds like a neat idea at first, but I don't think I want my safety riding on an LCD and a cheap camera...
I think a blind-spot camera could be good, but not as a replacement for the rear view mirror...I doubt it would pass most state inspections anyhow.
What about modifing a Marine Radar
Other solar car teams install these things (4-5" lcd, rearward facing camera) for a variety of reasons. It can provide a smaller cross section for wind resistance, and the camera and lcd can be placed more conveniently.
However, these same teams end up turning them off because they are practically useless (they put them in to meet requirements, but don't engineer them to actually work well), and they consume precious energy. In some cases more than would be wasted by placing a proper aerodynamic mirror externally.
So they turn them off (against the rules) for the best of both worlds - lower wind resistance, lower power consumption - but at the risk of being disqualified.
Furthermore, there is allready so little room in the cockpit, do you honestly think you can find a good place to put it? Outside the window is not only convenient, but frees up precious space inside the vehicle.
That being said, you'll need to look for a nice high resolution camera (broadcast quality tv or better) and matching LCD. These will be very expensive, but solar cars aren't cheap and I'm sure you can find someone to donate one.
Look particularily at what large motorhomes use. A local RV store ought to steer you in the right direction.
-Adam
The S7 is street legal and has a live video rear view mirror. It shouldn't be too hard to see how they did it. It might be expensive though -- the car costs $375,000.
http://www.saleen.com/auto/S7/S7con.htm
A small periscope type system?. You can get the rear view to a comfortable viewing angle without power or wind resistance, for the weight of a few mirrors. Adjust the mirrors' size/shape to get a good field of view.
"I don't know that atheists should be considered citizens, nor should they be considered patriots." George HW Bush
It sounds nice, and I've heard of similar ideas before (placing cameras at the base of the A pillar looking backwards, and colour displays inside), but here's my question: how would you then reproduce depth perception? Even with the mirrors on my tiny hatchback, the mirrors allow me to easily determine the distance between myself and other cars behind me. I wouldn't be able to do that with a two-dimensional image.
In Soviet Russia, Jesus asks: "What Would You Do?"
If you don't, it might throw people off . . .
I can't read 20cm letters at that distance in the rearview on my car unless I hold the damn thing still.
why not just use seethrough solar panels? (see www.sta.com.au) - DSC dye-sublimation solar collectors are cool!
You're probabbly out of luck for an electronic solution, for two simple reasons:
1) Depth Perception. Obviously, a single camera is not going to give you any sense of depth perception, so it could be very difficult to judge distances.
2) Focus. A camera is going to need to focus on a particular distance away, which will not be particularly helpful when attempting to drive any sort of vehicle: Anything particularly far from that focused distance will be fuzzy, unidentifiable, and difficult to nail down an exact position for.
"You know, Hobbes, some days even my lucky rocketship underpants don't help" -- Calvin
I'm doing some work designing a solar car for a certain unnamed university.
I've eliminated MIT and U of A as this unnamed university.
SCO (noun.)- A Slimy Corporate Ogre. Often seeks free money.
A friend of mine wanted to do this with his car, but with three cameras. Rear view, left rear, and right rear. (The selection was controlled by the use of the directional signal.) The only problem was that drivers wanted to watch the LCD rather than driver the car. :-(
A quick search with YFSE returns places like Marshall Electronics that produce plug and play solutions. A 4" active LCD will set you back about $225, but, will draw 400mA at 12 volts.
That does not include the camera, but those will use only 100-200mA at 9V. The unfortunate part is the camera and a lens to get the ability to read the letters you want to read are going to cost about $400-500.
Try www.mars-cam.com for more info.
----- Lotus Super 7 - A real car.
ObJoke about the 'typical' rush-hour driver not caring the slightest about anyone behind them when they change lanes...
To the poster: just swap out your driver right now with somebody from LA or DC and then you can just save yourself some money.
All editorial writers ever do is come down from the hill after the battle is over and shoot the wounded.
I've used tiny cameras from http://www.supercircuits.com/ for monitoring wildlife. The B&W cameras are very small and very sharp, yet cost as little as $30. Maybe match one with a tiny portable TV? (If they have the right inputs).
http://www.drayvision.com This product has an innovative roof-dome-mounted camera that quickly flips over (front-oriented view becomes rear-oriented view.) The LCD reverses the image as it flops over the top. There is an in-cabin joystick for pan, tilt and zoom control, too.
I worked on a project for the Future Truck competition. (see futuretruck.org for more info)
We installed a prototype system developed by the Donnelly Corporation that had a system of cameras (4 in all) and a computerized system that stitched them into a seamless rear-view image.
The proposed advantages were
-Wider field of view (less blind spots)
-A fisheye mode that would automatically switch on when the vehicle was put in reverse.
-Reduction of drag by removing outside rear-view mirrors
I believe that the total vehicle weight stayed about the same after we installed the system (The outside rear-view mirrors that we removed were the large stock ones found on GMC Suburbans.
There should be a moderation category "Dumbest Comment EVER"
I've driven in DC. Except for downtown (Which, like Arlington, doesn't seem to be contained entirely in Euclidean space), it's not that bad.
Boston, on the other hand... YIKES.
retrorocket.o not found, launch anyway?
You could rig a rear facing parascope. (No, not the kind you see in submarine movies with lenses so that you have to press your face against it. Just use simple mirrors and tubes.) You won't have to worry so much about malfunctions. It also costs less. Plus the image will be usable even on a bright sunny day.
you'd be risking your engineering degree by asking such questions. Keep It Simple, Stupid! The more complicated, the sooner dead. (our enemies have learnt these truths the hard way...)
Back to the point: think harder about a good spot for the rear-view mirror (or a system of mirrors), rather than using some out-of-hollywood hi-tech.
That's gut-busting! Should have been wrapped in the tags.
:)
Seriously, what do you do if your mirror falls off the windshield (glue goes)? Does the car explode? No. A proper car can rely on properly aimed side mirrors and the human neck to give a pretty good indication of what is going on on the road. If LCDs or HUDs were so problematic, they wouldn't be in use by the military now.
And I for one would like to banish the darn rear view mirror from its location in my Mustang. I find it actually occasionally blocks my vision somewhat out of the FRONT window. If I could drop in a HUD system (see through) or an LCD in the center of the dash above the radio, that'd be even better without restricting front visibility!
And I'll have to be sure to check my backup cranial-rotation system before I head out next time... want to make sure it is ready in case I need it!
-- Mal: "Well they tell you: never hit a man with a closed fist. But it is, on occasion, hilarious."
Try a camera obscura, it's perfectly suited for
a solar vehicle. It's light, it requires no electric power source,
it's solar-powered and you can control the image size.
You'd have to use a few mirrors to get the image
the way you want and where you want it and you'd
have to create a small viewing box. No big deal
and should be the cheapest way to go.
In case you're wondering a camera obscura (latin
for dark room) is more well known as a pin hole
camera. Anyway it may not be easy to devise one for your
apllication but it would be worth looking into.
(no pun intended)
http://tinyurl.com/3t236
other than the fact a camera obscura operates around f128, which is 14 stops less light, which works out to make it impossible to contrast to with normal viewing conditions. unless u add a photo multiplier tubes....
f128 is function of the size of the pinhole. It could be made worse or better.
The physics could be played with, I didn't say it was easy
and it may not be cheap. But it's solar-powered. They might need
to use some fiber optic technology as well as lenses and/or mirrors.
http://tinyurl.com/3t236
There are lots of marine systems available used on large yachts to do exactly this. Might be too expensive though.
I don't know about your brain, but there still seems to be depth perception after 18 feet and the brain seems to care about it.
It obviously varies from person to person and what they've been training their brains and eyes to do.
Yah but my point is there still seems to be a difference in depth perception when driving with two eyes vs driving with one eye. Tried it some time back to see how it would be like.
So I get the impression that stereoscopic depth perception is still present beyond 18 feet.
I dunno, try it yourself if you can. Maybe it's just my imagination.
how is this offtopic? yeah, its a first post post, but its the answer to the problem! Great solution!
It's not off topic but the article does say that an x10 cam won't do - reundant?