Running on a pair of CAN-bus nodes, these integer calculations (not just curving for the 2 axes, but deadband, speedpot range setting and different scaling for forward and reverse as well) are still using substantially more time than the CAN messaging, or the rest of loop () for that matter. As I can't move a joystick with anywhere near that precision, I figure that this is more than good enough, and if one of these five curves doesn't give me the right feel I can always try another combination of original and squared (or cubed if need be, but I highly doubt that). The results of these integer manipulations are quite close (better than 1% at all points) to the curves shown in the graph for the exponents shown in the graph legend. (2) making different linear combinations of the straight analog value and the squared value: (1) taking the analog value and squaring it (using long as the number can get pretty big)
In the stuff I posted, the four curves are generated by:
#Arduino map trial
Again, for joystick response, the thing we want is to get the right "feel" and that's something we're going to have to find out by trial and error. Same for things like polynomial curve fitting - computation intensive and overkill as well unless you want to precisely fit a curve who's characteristics you already know. For a real-time application, such as modifying joystick response, that may not be the best choice. That is a fine way to create an exponential curve, if you can afford the time and memory it takes to do floating point calculations.
#Arduino map code
It's probably not the most efficient code for this, so any suggestions would, of course, be welcome. (6) re-map Throttle and Steering in accord with a Speedpot connected to third analog input pin.Īs the results of these calculations are fed into a CANbus network, there are probably some lines of code that refer to sending CAN messages, and I have not included the #define statements or variable declarations that precede all of this, but this does illustrate one way that one can get curving and scaling and so on using entirely integer arithmetic. (5) re-map the throttle axis to a new when going in reverse, and re-map the steering axis, with different steering sensitivities when going forward or revers. The result to this point is illustrated in the attached graph. (4) applies five levels of scaling ranging from linear to squared. (3) maps the voltage to a -1000 to +1000 scale (distinguishing between forward/reverse or left/right). (2) establishes a deadband as no joystick will perfectly self-center. (1) reduce output to 0 for voltages 4.95 V as that indicates a broken or shorted lead or internal joystick failure.
Pulse Width representation with a scale factor of 147 uS per Inch.Attached are some procedures, from a much larger sketch, that I've used to scale and curve the outputs of a 2-axis Hall-effect sensor joystick whose normal outputs run from 0.05V to 4.95 V (assuming 5V reference source). Used to read in the pulse that is being sent by the MaxSonar device.
#Arduino map serial
This opens up a serial connection to shoot the results back to the PC console Long interval = 8000 // interval at which to do something (milliseconds) Int frontPin = 6 // front strip connected to PWN pin 5 Do I need to do something more complex where I detect the delta in the person's movement and use the loop to fade the LED from one value to another? Seems complicated.Īny help / ideas on this would be much appreciated! Existing code is below if it helps.Ĭlaudia //variables needed to store values Can I use a more refined number type to set the LED brightness other than int? Ideally, as the person moves toward the light, it very smoothly fades out in relationship to the person's movement/pace. I'm using map() to do it now crudely but it's way too abrupt and I'm not sure how best to achieve the effect I'm looking for. For example, as someone moves toward the sonar, the strip needs to dim. I'm using a sonar sensor to detect proximity, and need to control the brightness of an LED strip in direct relationship to the distance detected.
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