Hi,
Still wondering the best way to make this compatible with my pc.
Do I need to add a controller in the middle like a Basic stamp. Will the transducer understand PBASIC sentances?
Ultimately I think I want my computer to be dictating the sentances instead of a controller. Or do I have to have a micro controller?
Still trying to wrap my head around this.
Nobody has anything to say?
Well, I started typing you an answer some days ago, but previewing it, I decided that it would probably be over your head and only spawn a near endless series of questions on a subject that doesn't really interest me (no offense meant!)
Another thing that may be holding back answers is that you clearly haven't got any data on the sensors in your unit. It's impossible to work with something you haven't got data on and the results will almost certainly be inferior to the original display unit.
And your question opens up a potential can of worms (a huge can).
It's not enough to get signals that your PC can understand, you also need to have some software that can take this data and use it and so,there's 3 possibilities:
1) You don't have a program - so no purpose of the project.
2) You buy a program that cn make the data into something meaningful - and then the program will dictate what should go into the PC and in what format.
3) You intend (and are able) to make the program yourself - you have fairly free hands then.
You will definitely need to add a controller between the transducer head and the PC, but I'm not sure if the BASIC Stamp will do for the SONAR part of it.
The display unit that you have now (I assume) contains all the electronics for the transducer(s) to work and the transducer head is just the bare transducers. To interface them you need to know (exactly) what frequency/pulse width the SONAR sensor use (you output a pulse or a pulse train of a specific length into the transducer and then listen for the echo and the timing has to be very precise to be of any use at all), how the output voltage of the speed sensor relates to speed (or perhaps it's digital, in which case you need to know the relationship between clicks/minute and speed) if you get the head with that sensor (You either get an analog voltage or pulses).
The NTC (Thermistor), on the other hand, is relatively easy to find the resistance/temperature relation for (output is a resistance value.
A PC only reads digital signal (except for the sound card input, but it is limited (around 20Hz to less than 20.5kHz for a standard sound card), so you need something that...
A) controls all the timing issues and have a sensitive and selective amplifier for the SONAR return signal.
B) can communicate with your PC, which likely means that the controller has to have an USB connection.
If you're an ace at hacking, you could try to get the processed signals from your display unit, but were that the case, you probably wouldn't have asked in the first place.
At least some Lowrance systems has got a PC interface (so there's probably a program to use it as well) - might be the way to go.
If you just do it for fun, perhaps another boat related project would be better.