First prototype of a 700-LED 6-foot long staff. Some test animations towards the end, although I’m focusing on the physical design more now than the code. Includes an accelerometer to react to impact with the ground.
I’ll post updates about the second prototype, which puts the batteries and electronics on the inside, allowing for staff work (think martial arts), persistence-of-vision animations, etc. (in short: way more awesome)
This uses WS2812b’s, while the next prototype uses APA102c’s for the fast refresh rate. Questions are welcome! I’ve been working on this for about six weeks.
What is the difference between APA102 vs APA102c LEDs?
How long a run time will that battery provide?
Thanks for the behind the scenes pics. Looking awesome! Nice circular weld too.
Thanks, Marc! The 102c is the same LED housing as the WS2812 (non-B model). They are hard to tell apart. The 102 (non-C) is a new LED housing that has a square window instead of a round one. It is also ~2x as expensive.
This battery pack is ~10Ah, and the animations vary in power usage from 1.5A - ~6A, depending also on brightness. It’s a trade-off of course. So anywhere from 2-5 hours.
My next model has 17Ah of batteries, since in that one you won’t be able to swap batteries out (they’ll be deep inside the tube and inaccessible).
I see, thanks. So I guess a lot of places that are selling “APA102” strips are actually selling APA102C strips.
Cool, sounds like you’ll get some good run time. Let us know what the weight is of the final version. I forgot to mention I like the accelerometer integration too.
I’m curious what sort of batteries you are getting 6A out of. An article I read on the web seemed to indicate that about 4A might be the most you could get out of D cells, and even then the cell voltage would drop to about half. But I’m curious to hear real world info.
I made my own pack out of Panasonic 18650 Li-ion 3400mAh cells. I am using 3 cells. Each one can be discharged very safely at 1C (= in one hour). You can pull 5A from each if you need to.
Cool! So you are going to put them in parallel so you can have access to 15A? I was thinking it would be better to put my alkaline cells in series to get a higher voltage like 12V or 18V and then use a regulator to drop down to 5V. That way even if the battery voltage droops to half or less things will keep humming along. But I’m a relative newb here so curious how others approach things.
@Tom_Morrow , my biggest constraint with my project is space. I have to fit everything in a tube that is 20mm diameter. Batteries in series would require my exposing balance leads to charge them. I haven’t looked into converting down to 5v (or 3.3v in my case) with that kind of space constraint. I went for simplicity. I clearly need to post in-progress pics of the new staff.
But yes 5 in parallel, giving me ~15-16A of usable power (things seem to die when idle voltage gets close to or below 3v).
I’m building a similar light staff and for mine I’m using a 20C 11.1v LiPo battery with a 10A buck converter for power. How are you getting both gyro data and driving the LEDs? I’m using an arudino micro and it only has one SPI port.
I opted not to go with OPC and a fadecandy as I have on other projects because I needed the controller / controls to be compact and this would require two controllers (e.g. an RPI in addition to the FC)
I directly coiled the LEDs around the bar with the intent of later making a plastic enclosure to go over the staff. I’ll have to adapt the plastic tubing that will go over the staff to end pieces that I intend to 3D print in “the garage”
I think having default behavior of pattern cycles is better so for the 2 buttons for controls: 1 holds the current pattern / 1 to triggers alternate modes for the pattern
As mentioned before, power from LiPo because I already had awesome batteries from RC hobbies that can deliver ~150 amps of peak power should I want to get crazy
I tried to use an MPD6050 but my SPI was taken up by the driver lines for the NeoPixels on the Arduino Micro - I might try switching to an UNO instead in order to connect a Gyro because the heat sink on the power converter already is massive.
