Hi -
I do a lot of skatejoring (having my dog pull me on my skateboard) and in summers, I prefer doing it at nighttime as it is much cooler and less traffic for me and my dog. Right now the skateboard has just white LED lights powered by a 9 volt battery, and my dog has orange el wire on his harness. I want us to be a bit more visible at nighttime, so I'm adding neopixels to the front and back of my board. Front will act as 'headlight', but for the "brake" part my friend and I came up with an idea - using the doppler shift to show my speed. Using GPS tracker program on my phone, I've found my boy maxes out at between 25-30 mph during 3-mile runs. So let's say I want to set the doppler color shift to apply only between 0-35 mph, and have a strip of 6 neopixels in the back fade between colors as I speed up/slow down. I'm wondering how best to set this up - should I set a limit to the speed so that if I go over 35 mph (like, I forget to turn the system off and leave the board in my car..) it will not display any colors (blue-purple)...
Thanks!
Hi,
I do a lot of skatejoring (having my dog pull me on my skateboard) and in summers, I prefer doing it at nighttime as it is much cooler and less traffic for me and my dog.
Right now the skateboard has just white LED lights powered by a 9 volt battery, and my dog has orange el wire on his harness.
I want us to be a bit more visible at nighttime, so I'm adding neopixels to the front and back of my board.
Front will act as 'headlight', but for the "brake" part my friend and I came up with an idea - using the doppler shift to show my speed.
Using GPS tracker program on my phone, I've found my boy maxes out at between 25-30 mph during 3-mile runs.
So let's say I want to set the doppler color shift to apply only between 0-35 mph, and have a strip of 6 neopixels in the back fade between colors as I speed up/slow down.
I'm wondering how best to set this up - should I set a limit to the speed so that if I go over 35 mph (like, I forget to turn the system off and leave the board in my car..) it will not display any colors (blue-purple)...
Thanks!
Sorry mate, but spreading it out will make it easier to read.
I like the idea, the brake light GPS and the extra visibility is neat.
If you go over 35mph, I'd have an alarm that lets out an almighty scream..lol
Must be a damn strong dog too..
Instead of the extra lights being on the skateboard, I would suggest you do it in a wearable jacket, keep the lights up at a level that can easily be seen by car drivers.
Tom.... 
Just thinking: if you are going to use 6 neopixels in back, and, say, six more in front, your current draw could reach 0.72 amps. That will take a lot more battery than a 9 v. If your pixels in front are only going to be white, just buy the white LED's. But note how much current they draw, since some of the big bright ones are pretty power hungry. Small battery size would appear to be important here, so you may need to figure on LIPO's, which are at that capacity, fairly pricey.
TomGeorge: my bad, guess I just pour out everything in one go... I'll keep this in mind!
Yup, he's a red nose pit bull and bull mastiff mix, named Harley. Muscular as hell, I'm a wee bit chubby but... puts me to shame. As for the alarm that screams, it'd just bother him... I'm deaf, it'll come out peacefully quiet to me. 
The only time I'll do this at night or early morning is when it's hot out - for his paw's sake. Not likely to wear a jacket. A friend filmed me being pulled by Harley at night a bit over a quarter of a mile, and with the current 8 LED sequins (sold by Adafruit, wearable version - I had extras left over so decided to put 'em to good use) on the bottom of the board I'm easily visible.
jrdoner: Agreed, I plan to upgrade the battery to perhaps 2500mAh LiPo, just need to design a secure case for it to be mounted on the bottom of my board.
way I see it, I'll put four or six LED sequins in two groups of two or three up front, two individual neopixels on each of the sides, and a strip of 6 neopixels in the back. Front stays on at all times powered by its own battery; the four individual side neopixels connected to accelerometer and usb boarduino, and the same boarduino controls the 6 neopixel strip with GPS for speed and somehow... reflect the speed using doppler shift colors.
I don't have a strong background in mathematics, but I'm able to look up the equations online and figure out how to code it, but I'm looking for guidance on how to set up the colors to only show the color shift from 0 to 35 mph. I can set it up to stop showing colors over 35mph, but can't think of an effective way to plug in the color shifts.
Thanks!
Hi Rabidgeek,
Why don't you buy a new one with these specs? So, you don't have to moderate this one I've been using longboard it also doesn't have the light in the back, It's actually Bamboo Longboard from HyperOutdoor brand and with the 7-inch diameter.
The FastLED library offers HSV colour coding, that makes the colour shifting rather trivial, you just map your measured speed to the hue you want to display.