Thank you for all your answers.
netoperek wrote:Since You'll make it on at least one uC....
Neo, you have to see how the industry works.. they charge you hundreds for absolutely everything, you can get charged 100, 200usd for a couple more inputs. Just because you have them, doesn't mean you have to provide them just for the sake of it. GPS is something that is really needed(almost exluding) which I can provide for the fraction of the cost. We are also doing this as a subject so if we say we'll add a lot of digital inputs, then we actually have to do it to pass the subject.. so we're trying not to overload it with things we will not be able to do, when other things are mor important.
We are aiming for multichannel ADC chips.. 8(or more) channels, 10bit. We'll see how many of this we use. 1Khz is not much for electronics system.. but it's already a lot for the frequencies involved in a car. Remember I only need to sample( ideally) at twice the maximum frequency.
Safety features is something we will definitely work on to avoid "one error, no more data logger" type of situations.
As for testing.. we'll work our way up. Most probably we will buy the ADC and test the anti-alias and sampling frequency required (we'll probably need some digital filter). A 10 bit system has a 62dB noise floor.. we are definitely not making 62dB filters. So we'll have to do a simple analog filter, over sample and then apply a digital filter. This is a very critical problem since it defines the quality of all analog inputs. I'm not sure how it's done in other loggers, but probably it's something similar, I have read some Motec just have 150Hz 1st order filters which is definitely not enough.. but don't know how noisy the environment is(maybe it's just high frequency noise). Once that problem is solved, we'll focus on the next one and so on.
Jersey Tom wrote:CAN is quite nice.. but if you're ...
We'll probably dismiss CAN to focus on other stuff we could improve. Though it's a nice feature to have, it's not paramount (but it avoids some repeated sensors). It will have no display at all.
The bluetooth would be something that would seperate us from the rest, and it could be quite simple, we're researching about that.
This post is in part to know the weights of features for a decision matrix. But since we have no actual experience using this (excluding rfactor) we need to talk to people who use it.
andylaurence wrote:<span>Entry level might be about to..
Though race capture pro seems like a nice entry level option, there are several things I don't like. It's not simple enough for the guy who knows no electronics at all. You need to build your own pull up resistor for resistive temperature sensors. It has no thermocouple inputs. The input/output connector is really bad. If you need to take the logger and put it in another car you have to unscrew every single wire and then who know which one is which. I'd prefer one big large connector.
Calibration is vague.. only 5 point curves, which you can't acquire online. I'd like to say "get current data" that's 5mm... "get current data" that's 10 mm and so on.
As for the inputs, I agree with you. ECU interface is CAN, and the inputs you have listed are analog or digital, bar the gps and accelerometers.
Telemetry is exluded from the project. Mixing something that's not top level with telemetry doesn't seem like a good idea at the beginning and it's mostly prohibited.
Totally agree with you with the software stuff. It's what makes the whole data useful. We'll try to build something modular (drag and drop graph, bars, dials, etc) but it's something we'll focus on later on.
Our basic approach is to have something simple, basically plug and play, get the sensors connect them and use it. If you need to be an engineer to use it, we have done something wrong.
marcush. wrote:I´m by no means an electronics guy bu...
Racing cars of people who work with lower budgets don't have all that technology and sensors. Even lot's of categories here still use careburetor. Though if you have fuel injection having to get another crank sensor for RPM is annoying when you already have one and could be provided via CAN. We're focusing on race cars for the moment, but it would be essential if we weren't.
Thinkg of the average joe racer who wants to improve his car/driving. You'd get the system get the most important sensors( gps, accel, steer, throttle, brake, rpm) and you could already do a lot with that.. that means buying the logger and a crank sensor, two linear pots, and one rotary pot for the steering. Of course you can get into more complicated stuff getting damper position, wheel speeds, etc etc. Thermocouples go around for a couple of usd.. so you could add some into the engine (thermal protection) or brake discs.
The possibilities are endless.