No reason at all rray. SNO
There's no reason I cannot just connect my Ign +12 to the board and leave the red 12v wire from the OBDII cable disconnected is there?
Also, what is the function of the jumper next to the board's USB Input?
I am using the cigarette lighter's circuit as my Ignition +12v supply for my switched 12V because it has plenty current suitable for a heating device (10-15A), and is only available when the ignition is on. Oh, and my car did not actually come with a lighter in that socket, or ashtray, those are aftermarket accessories nowadays.
For the next version, I would like to suggest the board add fused switched 12V and 5V utility outputs, and a switched USB 3 hub.
Now that I have USB 3 ports on my cupholder console, transfering many gigs of music, or doing a full windows image backup to USB 3 thumbdrives goes very fast, and I canno ever do without USB 3 on a carpc.
Last edited by rray; 07-26-2014 at 05:16 PM.
There are 7 port USB hubs available. If I am not mistaken you could actually have the power come from a regulated 5 volt source directly instead of the actual hub.
On a site I am on they have an OTG cable connected to a powered hard drive from their android tablet. Normally the hard drive will not run directly from the Tablet only because the tablet can not produce the higher output needed. However they take a 2amp output USB from a USB battery pack and take the power and ground and splice it into the cable. They disconnect the power lead from the tablet. This then powers the hard drive fine and the tablet is happy too.
Another variation you can get a Y OTG cable that hooks to the tablet and a battery pack or charger. This cable will allow the tablet and the device to be powered or charged from that battery pack or charger.
I believe you only have to share the grounds for it to work properly. Regardless if you power the hub from the seperate power source and cut the wire from the computer or not.
I am hard wiring a 2 amp USB charger to a 4 port powered hub I have. They just parallel the input with the computer power. I decided using a $7 USB charger and hack that up rather than trying to make a regulator board to do the same thing...
If you use a 7 port USB hub you then can provide additional ports. Also would be cool if you could use USB 3 ports. They will work down to USB 2 if you want but for someone with USB 3 it would be a little nicer for the extra ports at least.
I figure if you are adding a hub might as well go with a 7 port instead of 4 port if you can...
JP3 is to disable the leds on is enable ledsAlso, what is the function of the jumper next to the board's USB Input?
JP2 is to reset the NVM on the obd2 chip
JP1 is LP out on the obd2 chip
switch 2 is something to do with sleep on obd2 chip
switch 1 is reset obd2 chip
info in the microobd2 functions here http://www.scantool.net/dev-tools/mo...roobd-200.html down near the bottom stn11xx-powersave.pdf for info on jp1 and switch 2
I just used their reference development design and it's not really used for basic obd2 stuff also check your inbox for link to schematics SNO
Hey sno, quick question for you.. I can't find a good place in my truck for the box.. I am thinking of getting some plastic stand offs and mounting the boards side by side on some perf board to mount them inside my dash. The height is a problem but if I make them short but long that isn't a problem. Just worried that leaving an exposed circuit board inside my dash might be a problem. Thinking of grabbing some acrylic and maybe making a sort of "sandwich" with the acrylic on the top of the box.
Probably could just make two "sandwiches" and just use the acrylic box top and bottom as my new tops and make the perf board bottoms.
I have mine under the rear seat where I have my computer, it is also central for the TPMS signal from the tires. I really don't see a problem makingit longer and extending the power and 4 wire jumper cable. remember you don't need to use the obd2 cable since you are only really using 4 wires out of the 8 canhi/canlo/12+/12- Good luck SNO
Wait a minute... The OBD II. I have a canbus based car, so I only need 4 wires? So, since I have IGN switched 12V and GND where my carpc is located, can I just tap into the Can Hi and Can Low wires on the backside of OBD II connecton and everything will work? If so it leaves the socket available and I only have to run a 2 conductor cable.
yes it's true! That's how mine is setup in my car, just tapped into the can hi/lo wires on back of obd2 plug. You really only need the plug if you are moving from car to car and they are all different ages and different protocols. More like a tester than fixed to car. SNO