Beginner Questions and recommendations

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1

(Hope I’m posting in the right place.)

I’m a windows system admin and vb.net developer but have no experience with electronics directly, however, I have an older car that I’ve wanted to put a car computer into for a few years now.

My car is pre-ODBII so I can’t just hook into the system and get a bunch of information.

So… I have 2 questions.

  1. Is there a way that I connect one of these Gadgeteer boards to my (as a for instance) speedometer circuit and read the voltage (?) change. I’m guessing that if I can do that, I can then write to code to display the proper speed based on the voltage. I’ve seen the voltage sensor, but that doesn’t seem to be made for 12v DC. I’m thinking it would be something that allows an analog dc powered connection. I just know enough about this stuff and the descriptions/documentation seems to be very spotty.

  2. Is there a way to connect more than 1 T35 Display modules? I’ll explain. I would like to replace my gauge cluster’s instruments with a touch screen display, however the space available is roughly 12 inches by 5 inches and there are no monitors made in that size. When I saw the T35, I thought hey… 3 of those would work perfectly… only to be disappointed when I found out only 1 can be connected to a main board.

It is possible that I could fit a smaller 7" screen in there but I really like the idea of the 3 separate screens. Even to the point of considering purchasing three boards and then figuring out how to make then “talk” to each other.

Thanks in advance to any responses…

2

Welcome to the community Campbell!

Search the forum for ‘Bike computer’. The concepts for reading the sensors are the same.

I like the multi screen idea. There would be a few ways to accomplish it…

  • Connect them in parallel but control which one gets the Enable signal through a logic circuit.
  • Use serial displays on a bus. Like http://www.4dsystems.com.au
  • Run 3 systems with comms between them.

I speak under correction but I think VB is coming to NetMF soon.

3

You can attach more than one of Seeed’s OLED displays, they go in type S sockets, so you could make an instrument cluster out of one central T35 touchscreen display and two satellite non-touchscreen OLED displays at the sides. No idea about hooking into speedometer circuits but you could get a decent speed reading from a GPS unit - still leaves you a few instruments short of course.

4

Yeah, I had thought about the GPS option. The OLED displays are a good idea though. Thanks, I’ll check them out.

5

Dont mean to poop on your parade, but if your car is pre-ODBII, it likely uses a mechanical speedometer. This doesnt mean that its impossible, just more difficult.

6

My car is actually ODB1 and it does have a Vehicle Speed Sensor. I am also looking at interfacing with that.

Another problem is that it still doesn’t cover things like the Fuel gauge sensor.

7

Just ran across this. It might give you some ideas.