Basically, I want Arduino to output to a Serial LCD, store information to a USB flash drive, and communicate with a computer or a second Arduino via a wireless signal. Also it will need to have some sensor inputs and basic buttons for inputs from a user, not sure how many buttons at the moment, but at LEAST two, probably more like four. Also possibly some LED's to light up here and there...
As I understand it, all these tasks are more or less best done through a serial connection (excluding the simple buttons and LEDs of course).
*My questions: * Is it possible? (I think it is based on addressing packets to specific hardware, but its slow?) What's the best way to do it and/or suggestions on how to do it? (mind you I already have a serial LCD, the other hardware has yet to be purchased)
None of the serial connections need to be particularly fast, they're actually second order compared to the button/sensor inputs. The sensor inputs are by far the most important, and need to be read as often as possible while maintaining a reasonable output to the LCD and/or wireless and/or USB. USB data needs to be written only as fast as Arduino runs out of memory for storage. USB data needs only to be read after all the data is collected, in fact, it might not even need to be read by the Arduino at all, but rather by a computer for simple data-logging. Precision trumps accuracy.
In the case of using two Arduino for the wireless aspect of it. I would need one to write to an LCD and a couple of LED's only. The other, theoretically only would need to output to a laptop, but seeing as how I'd like this to be standalone, it would probably also have it's own LCD and also the USB storage for when our laptop invariably runs out of battery.
For specific information on my application: (this gets long)
This is my first project and it is relatively simple.
I need a "stopwatch" for essentially a drag racing strip, something that is triggered by one sensor at the beginning and another at the end. Basic requirements are that the trigger is by a sensor that is much more accurate and repeatable than a stopwatch that is controlled by a person.
We actually have this system in place by wiring infrared sensors (the sort you find in a store to signal someone entering the store) into a stopwatch. The problem we have is that at low speeds the car can trigger these sensors more than once, so we also need a debounce filter, preferably one that is even programmable for various different situations. Also it only reads to .01 seconds, we would prefer .001
This is relatively simple and actually the LCD display and sensors have cost quite a bit more than the Arduino itself, yet the Arduino is the real key to the project...funny how that is.
Anyways, I have all the stuff to make that work and some rudimentary code in place that will get it working (will be making a thread in the 'exhibition' section within a week or two) but I'm looking towards the future...
I recognize the power of Arduino and the sorts of hardware out there, as such I've become increasingly more interested in using Arduino for a data-logging/telemetry system.
At first, this will only be recording lap data. That is, the Arduino will only read lap times. The first thing to do to make it more complicated is to have it read sector times, as well. These are checkpoints out on the lap so that you know how fast you complete certain sections of the track (this is not for a drag racing strip, this is for tracks that are continuous). A lot can be done with that data. I would like lights to light up in the drivers face if its the fastest lap so far, or fastest section. I would like Arduino to remember which laps were fastest. On a more complicated level, it could do very simple data calculations such as average lap time and standard deviation. Arduino itself only needs to remember a select few bits of information: fastest lap, fastest time for each section, average lap time, standard deviation, but all the data should be saved in a raw format to memory somewhere (USB flash drive?). On that note, I don't know mathematically if you can calculate standard deviation and averages and all that stuff by taking a known average and standard deviation and factoring in the new lap time... I assume it's possible... worst case scenario I have it be a rolling average. On that note, we rarely do more than 20 laps at a given time. There will probably never be more than 5 checkpoints and/or sectors, so really there will only be about 100 pieces of recorded data in at the base level of this project.
Thats what I want to start. In the future I see telemetry so that the driver and the pit crew see the same information (although the pit crew would probably get more detailed info, due to then not being proccupied by driving) I see more complex data logging from a variety of sensors. Possibly even some control over variables on the car.
Currently, I have an Arduino Diecimila. Since things will be mounted on a race car, I will most likely be using an Arduino Mini, when the time comes. Similarly tiny wireless devices are desired. Range should be ~600 feet outdoors. Less is acceptable if it can be made to send the data when it's within range and not when it's out of range (for example, sends the data when the car is driving by the pits), but not when it's 1/2 way around the track).
Thanks for your help, and taking the time to read this!