MPG LED Display Panel for others to see Death Wish

If that happens press charges.

Glad I don't live in the USA.

 

I actually had this idea back in May a couple months after getting my Prius. I got an LED screen from work, now I just need to figure out how to wire it into the computer that measures the MPG.

 

I too, have had this idea. If Toyota ever needed to sell more Prius, all they need to do is have a display of average and instantaneous mpg displayed on the rear of the car.

 

Take a look at feeding an external display from a ScanGuage. It would be easier interface to design.

JeffD

 

You are being too technical for no reason. Just build the display so -you- set what it reads. Adjustment/drive from the inside of the car. Set it to match the MPG average display once a day, if you like.

 

Right, don't take it from the MFD, take it directly from the CAN bus, like CANView or ScanGauge does. Over at GreenCarCongress I think there's some pretty technical discussions on the ScanGauge and how to send your own codes (using SG, but the same principle applies) to the CAN. The OBDII port contains power for a SGII device, but I'm not sure it would power a large LED display. Might need to power that off the cigarette lighter.

Show tank average and current, last five minutes would be good as well, not sure if you can get that, but the SGII will show average for the current trip. Not sure if it's doing it's own math for that (probably requires a simple microprocessor) or if the car supplies that number (keep all logic in an FPGA).

But then it would lack the authenticity of something that updates in real-time, as you accelerate and coast.

Could put this in the lower part of the back window, if it's not too show-offy then there's less risk of negative behavior by other drivers.

 

the scangauge calculates its own values. You'd be hard pressed to have a display interface with the scangauge UNLESS you took the scangauge apart and used the output for the scangauge screen to drive the external display...

 

I know that you can purchase CAN bus interface cables for PDAs and laptops. All it takes from that point is a small script to drive an external display via serial interface or USB, it really wouldn't be too difficult to make it wireless, if one were so inclined and properly motivated.

 

I have a friend who wants to build a device that incorporates 1) an LED display 2) a position sensor and 3) a camera.

A tailgater would see in order, 5 seconds or so apart:

PLEASE STOP TAILGATING

TAILGATING IS ILLEGAL-CAMERA ACTIVATED

PHOTOGRAPH BEING UPLOADED TO STATE POLICE

The latter could be a bluff or for real depending on how much additional hard and software you wanted to put in.

 

To simplify matters why not use something like this?

Google "Scrolling LED License Plate Frame"

Looks like it update it via remote control. Not automatic but no interface needed

 

Yeah, I had been thinking about doing the same. Cheapest way would be to develop a uC board to read the CAN data and interface to the LED board. Would be a lot of work though. A car PC/Mac could pretty easily be setup to do both I would think.

Rob

 

I like it

 

LED license plates may be illegal in some areas.

 

As in NY state. I was going to get one, but on the advise of my friendly sheriff's deputy, I did not. I got undercar LED's instead (in blue, also questionably illegal while driving). Other mods have followed and my life has not been the same.

 

I actually did something like this when I had my Honda Insight. I was using some rather large 7-segment LED's that I managed to find by scouring the internet, a rather nice guy sold them to me. I had measured the space I intended on using and looked at the specs of the LED panels and they were a perfect match, in fact they were so perfect they nearly held themselves in place just by wedging them in, but I did have to use some adhesive foam tape to keep them in place because hanging upside down with hatch open and slamming shut knocked them loose.

I was very quick to run wires to ground and 12V power from the fuse box, wired up ground to one pin on each panel and applied 12V to pins for each segment I wanted illuminated (was able to do this on a 12v/ground rails of a breadboard to make it easy) and it illuminated brilliantly and was very bright at night and visible in daylight. Unfortunately, in my haste and enjoyment I did not bother to use resistors in the circuit and after a few days began to burn out segments. I wasn't sufficiently knowledgeable in electronics at the time, but I was having fun. I really didn't want to buy new panels and build the entire circuit so the project was abandoned.

What I was going to do was make a few runs of cat5 to get enough wires to each of the segments and have a controller accessable from the drivers seat with a potentiometer and small 7-seg displays and just duplicate the powered segments to the rear display. The pot would be wired to an IC chip that could turn segments on and off like a counter as the pot is adjusted, I had a lot of the schematics at the time and I was taking some digital and microcontroller classes at the time. Anyway, one day I got a Prius and the insight was up for sale.

I really think pulling the data on the prius from the CAN bus would be the most logical idea I know of, then some sort of circuit would have to be built to control a display.

Here's a few pics of the little success I managed to accomplish with the Insight:

http://hometown.aol.com/ilusnforc/images/cars/display_03.jpg
http://hometown.aol.com/ilusnforc/images/cars/display_04.jpg

 

a liecence plate frame that has a led readout on it would be pretty cool. ive seen them, just use that to display the mpg. that should be discreet enough to keep from geting gas hogs from acting out on there ignorance.