Adding guage display when there is no ODBII??

CodyGrizz · 12-23-2006, 11:45 AM

OK, question. In the process of redoing my 19' Bayliner Capri runabout with all new interior and audio and want to do a computer as well to run my MP3s and such (still not sure if I will use a frontend as for music I use my MixMeister Pro) and would love to do digital gauges on my display like I see in ODBII setups. Now as its a boat engine and no computer, all we have is wires that go to our gauges. I know I can use GPS for my speedo but any options for other guages?

Figure I would ask here. Thanks for the help folks!!

hermand · 12-23-2006, 11:56 AM

I've been looking quite heavily into this (For an RV, though, not a boat) and this is what I've come up with (NB: This is purely a shopping list at this point - no testing).

In my case all of my sensors work with variable resistance (So, for example, with my temperature gauge the resistance goes down as the temperature rises).

This means that we have to measure the voltage drop over the sensor. The easiest way to do this is to have a static, regulated input voltage.

So far, the best bet seems to be here:

http://www.phidgets.com/

The 8/8/8 Analog input device and the voltage sensor.

Here is the diagram of how I'm (planning) on doing it.

With the blue square beign the standard sensor, the red square being the Phidget Volt Sensor and the blank square beign a resistor. The power supply would have to be a well regulated source to give an accurate calculation.

It would then be a case of either contacting the sensor people and seeing if they can provide some calibration info, or actually sitting down with your current dial/display and working out what voltage corrosponds to each reading.

Then it's just a case of plotting a graph and doing some maths in VisualBasic or the programming language of your choice.

Sadly, I'm finding precious little resources for this kind of thing - so it's been quite a challenge for me just to get this far as I'm in no way an electronics expert.

DavidL · 01-07-2007, 10:14 PM

You can also look into 1-Wire technology. Several of the home automation software (like MainLobby) supports graphing and display of 1Wire device values.(like voltage / temp / humidity etc)

FordTough99 · 03-22-2007, 04:09 PM

hermand...what type of temps are you wanting to measure? I built an EGT meter using an Analog Devices AD595, which is a thermocouple amplifier that you can use to measure cylinder head, exhaust gas, water and Oil temps. I would like to build a boatputer that has an engine monitor display. This is similar to Mercury's smartcraft gauges now.

sbkenn · 04-08-2007, 03:59 PM

For those who need input interfaces for gauges...look for "Adam" series modules..there are several on eBay. I just bought a bigger unit...a DataSCAN 7320, which has 16 individually configurable analogue input channels.