hi,
Its the symbol for a polarised capacitor.
The flat line represents the postive terminal and the curved line the negative, most likely an electrolytic or tantalum cap.
The AD7490 uses a totally different communication method, between the PIC and ADC0808.
It would mean a revised circuit and a new program.
hi,
Its the symbol for a polarised capacitor.
The flat line represents the postive terminal and the curved line the negative, most likely an electrolytic or tantalum cap.
The AD7490 uses a totally different communication method, between the PIC and ADC0808.
It would mean a revised circuit and a new program.
Thanks for the cap info, I sort of guess that might be the case but thought I'd ask just in case..
Bummer, is the only diagram I could find that keeps things nice and simple and does almost exactly what I want (Apart from me wanting to read 16 analog sensors)..
Any ideas on how to move forward, a multiplexer was suggested with 2 0808's, but I have no idea what to search for on RS and how to implement it with the 0808..
have done some programming in the past, C, perl, python.. Did some asm once on my Amiga when they first came out !!! Am, sure I could pick it up pretty quickly, using ref mans and such
I am assuming that you want to monitor, 16, LM35 temperature sensors?
What do you plan to do with the analog signals once you have captured them.?
Like to help, but we really need more details of the project.
It's for monitoring temp and pressure sensors that are already on an engine, the data I want to stream to a serial port. Linux live cd type system with GUI monitor console etc...
Once I can start sampling data I can get the fine details hashed out and looking slick.. That side will only take a few days.. Is the hardware side I am having the problems, i have fiddled and dabbled in electronics before, but am finding I'm out of my depth, but am willing to learn..
Why don't you contact the designer Abbas Raza?
The LM35 also has a maximum temperature range 150c, an engine would probably be much hotter.
**broken link removed**
Why don't you contact the designer Abbas Raza?
The LM35 also has a maximum temperature range 150c, an engine would probably be much hotter.
**broken link removed**
I'm not planning on using the LM35's they were just what he had put on the diagram, as I mentioned I am hoping to be able to use the sensors already in place..
The sensors are earth return (two wires, + and - ) all the sensors I have tested/checked so far just use resistance.
So based on that my plan is to put a measured voltage through (5v) and measure it, the output then sent via serial to a PC which can then with simple algorithms give a "readable" output (is actually going to be gauges). Goes without saying there will be some basic calibration involved, this will be sorted with a config file for the software on the PC.
My idea is to have the PIC do as little as possible (As I know more about PC/Linux programming) then I do about the PIC side of things, my asm/C isn't upto the task at the moment.. Maybe time to start ?
Sparks
P.S. I have contacted Abbas Raza, the circuit designer for some input as well, and he has sent me a very nice email saying he will have a look as well
Part numbers ! They are not available it is a Russian Shvetsov Ash21 engine, and is about a 1000 years old ! (Ok, maybe a bit of exaggeration there)..
Slight change to angle here, maybe it can be simplified ?
Throw 5v down the line, measure the voltage that comes back, send data to serial port.. I guess thats what the ADC does ? (Thinking out-loud!)
I did not honestly think it would be this complicated to need part numbers, as has already been said "the devil is in the details".. On paper it does sound simple and using a multimeter I can see the resistance change, so in my simple world I though all I needed to do was measure the resistance and squirt it to the PC for that to process the value sent and display accordingly..
However, this has really got the "old grey matter" working on trying to follow what and why these questions are being asked so I can try and solve the problem, or at least understand any possible solutions put forward..
You've got to figure out what those sensors are, they are probably millivolt thermocouples and you'll need some signal conditioning before the A/D to get any useful readings.
What is the resistance change, have you made a chart? Min / Max?
You've got to figure out what those sensors are, they are probably millivolt thermocouples and you'll need some signal conditioning before the A/D to get any useful readings.
What is the resistance change, have you made a chart? Min / Max?