kph to mph

Projects Programming
1

hi all, a little help needed.

kph / 1.609 = mph so i have seen on the internet but i don't know how i would do this in arduino. do i have to use a float?

thanks.

2

As you ask, the answer is "Yes".

However, to work with long, you could easily multiply by 10000L, add 5 for perfect rounding, and then divide by 16090
to get mph from a km/h value.

int mph = (int)((kph * 10000L + 5)/ 16090);

BTW: rounding assumes you work with positive values.

3

thank you michael_x, i will give that a try and yes it's positive numbers.

thanks.

4

Just work with metres instead of kilometres (ie everything 1000x larger) and format accordingly for display.

Rob

5

the value am reading is kph via a cars obd and i can't change that.

6

michael_x,

int temp;
temp = ((kph * 10000L + 5)/ 16090);

that worked fine but this also worked fine but only returned a value with no decimal. i don't want the decimal anyway.

int temp;
temp = str[0] / 1.609;

this is what i have done now and it looks to work fine.

    case VS:
    temp = (str[0] * 10000L) / 16090L;
    sprintf(PID_result, ("%d MPH"), temp);
    break;

thanks for the help.