MyCANScan, graphcan on the EEE PC

Hi David,

Hmm, that 1.95 volts for the 3 diodes. Need a drop of 4.0 volts or more like 6 rectifiers. And at 2.5 amps, that is 10 watts. 1N400X, 1A Rectifiers are common enough, but do not have anything of higher current rating handy. And at 10 watts, it would need some heat sinking.

The PS should work, nothing is fried on it. I think the problem is just sloppy PCB design and assembly.

 

Actually, if you check the data sheets, you'll find most silicon "rectifier" diodes drop 1 V at any current worth using (more than a few mA). There are 1 Amp units such as the 1N4000 series you mention, then there are 3-5 amp units, some of which can handle up to 20 Amps if heat sunk. If the diode is rated at 5 Amp it usually does so with no heat sinking. Yes, they can get warm, so don't rest them on plastic, just in case. I like to let them stand off the PCB to get good air flow.

You said you wanted 10.7 V, so three diodes would work from 13.8 V (the Prius system voltage).

 

Hi David,

Welp, its been a week without a power supply drop out. So, I think its fixed.

Oh, and its 9.7 volts that the EEE PC wants. And the switching power supply is going to have allot less power dissipation than the diodes. So, I think I will stick with it.

 

Shortly after I purchased my Pruius 3 years ago, I found Atilla Vass' Graphcan, and started to work on puting it on a Zaurus, which needed some mods because the screen that I had was different then his. I got the code working, and then the serial port died. I then saw this thread, and learned about Peter's work, so I switched gears, and got a Skytex netbook. I got the code compiled and running on it, but could never get the USB drivers to work properly, so I sold it, and got a Eee PC 900A for $70 on Ebay. I was able to get everything working on it, but not with the OS it came with. I had to use Puppy Linux. I picked up a 2nd Eee PC, 701 and got everything working on that. There are still a few bugs, and improvements still needed. I installed it in the car last weekend. The biggest issue is boot time. The Puppy Linux, which is suppposed to be fast, takes 90 seconds to boot and load Graphcan. In Atilla's and Peter's version, there are no labels on the screen, so unless you memorized everything, you don't always now what you are looking at. I added labels to most of the data. I also modified the program to turn of the Eee PC after the car shuts down automatically. I also made a hardware mod in the Eee PC that turns it on when external power is applied. That needs some improvement. It works about 1/2 the time.
What I need to work on is:
Boot time
Ability to quit program in full screen mode, text input is not working
Minor bug that overwrites the graphic of the car when a door is open.
Auto Power On

I have some pictures of the installation. It fits perfectly under the radio, if you remove the door from the cd storage slot.

 

Nice! Right now I just put the EEE PC on the corner of the dash so it's easier to see. Eventually I would like to do a more permanent installation with auto on/off as well.