– arduino – controlling a ws2812 led strand with neopixel or fastled gas tax in new jersey


First of all the resistor does not “drop” any voltage. Resistors only drop voltage according to how much current is flowing and in this case when the input impedance of the WS2812 is very high there is sod all current flowing so there is sod all voltage drop. What is happening is that there is a transmission line situation, especially where the LED strip is some distance from the driving source. So a rising edge on the driver hits the mismatched impedance at the LED and reflects the signal back, this gets reflected back from the low impedance of the driver because again there is a miss match and you get a standing wave on the line. 3 main gas laws The resistor is there to absorb the power in this standing wave and damp it down.

Now as to the question of why not use a capacitor. If you used a series capacitor then driving one end of a capacitor at 0 to 5V would produce a signal of -5 to +5V on the other end. The -5V would kill the LED and would do nothing to suppress the standing wave. If you put the capacitor in parallel, that is from the input of the LED to ground then you degrade the rise time of the signal and so it would not work. Reply

The resistor isn’t needed to protect the Arduino from standing waves or we would see them used quite often on outputs plus the Arduino output is capable of handling currents up to 40ma and any reflected wave would be so small it would be almost impossible to measure. The real reason for the resistor is that many have had the first LED in a string fail which can easily happen when the LED string and Arduino are powered from seperate power supplies and either the Arduino supply is turned on first or it powers up a bit quicker than the LED power supply. When this happens and the Arduino output (which can supply up to 40ma safely and even much more current into a low impedance load) is HIGH, 5V will flow into the input of the first LED and end up trying to power the LED string which will result in more current flow than the input can withstand and distroy the input. Yes, the input is normally a high impedance input, but only when the LED is powered. Without a schematic of the LED circuit is hard to say exactely how 5V on the input reaches the 5V input and tries to power the LED, but it’s common practice to use diodes on high impedance inputs to protect the input and I’m guessing there’s a diode from the input to the 5V rail. These diodes are usually rated for no more than 10ma so would quickly be distroyed by 5v from an Arduino which would then result in the input circuitry also being distroyed. gas and water Anyway, A 470 ohm resistor will limit the current to no more than 10ma and allow the input protection diodes to do their job and not affect the signal when the LED is powered and the input becomes a much higher impedance.

/Users/claire/Downloads/ -c -g -Os -Wall -fno-exceptions -ffunction-sections -fdata-sections -mmcu=atmega2560 -DF_CPU=16000000L -MMD -DUSB_VID=null -DUSB_PID=null -DARDUINO=106 -I/Users/claire/Downloads/ -I/Users/claire/Downloads/ -I/Users/claire/Documents/Arduino/libraries/Adafruit_NeoPixel /var/folders/8t/mjxdbzp94zqff5dvs84yk4s00000gp/T/build7107361827568138670.tmp/sketch_nov10b.cpp -o /var/folders/8t/mjxdbzp94zqff5dvs84yk4s00000gp/T/build7107361827568138670.tmp/sketch_nov10b.cpp.o

To use our example code for Arduino, connect the yellow wire (serial data) to Arduino pin 2 and the green wire (serial clock) to pin 3. The software can be configured to use other pins, but we recommend using this arrangement when starting out, so that everything is tested in a known configuration. The blue wire (ground) should be connected to any of the Arduino GND pins.”

I’m wondering if someone could help me here with the concept of “Interrupts” as I know FastLED does not like them all that well, but it’s not just the FastLED library. It’s just about anywhere I use the good’ol fashion “delay” depending on it’s duration. I’ve spent entirely too much time digging more into using “millis()”, just can’t seem to get my head wrapped around it…must be getting old, but I can do the heck out of C#, just not C itself anymore.

I took an excerpt from a gentleman on YouTube and began playing around with it adding serial functionality. His excerpt, I put into the function “rainbowCycle” which believe it or not, I can hit the “1” key on my keyboard, it starts right up and I can hit the “9” key and it stops immediately over and over. However, when I use the other function “colorChase”, it starts with no issue but whenever I try to interrupt it by hitting the “9” key, it seems to want to continue the loop until the “delay” is done, then displays “Quitting…”. Why would his rainbowCycle one work to interrupt immediately with the press of key “9” which is also using delay, but the other function will not? Is it more than likely because the “delay” is in the for loop being iterated?

Yes, an American Flag. I have the matrix set at 30 columns by 8 rows. I took a 240 LED WS2812 strip and soldered it together. The strip works perfectly, but with my limited knowledge I’m having issues. electricity lesson plans 4th grade I’m interested in functions and arrays, if statements and loops, and I understand the concepts, but I have zero experience, and I simply want to start with being able to address 240 WS2812 LEDS individually. Once I understand how to turn them on in RED, WHITE, and Blue, then I will try to do some studying, and learn to do more. I have ordered this book, so I’m hoping to learn more. Programming Arduino: Getting Started with Sketches, Second Edition

I have installed the NeoPixel library as well as the FastLed library. I have run the examples that you posted above with no issues. Any help would be appreciated. Also, if you have any recommendations of where to start for beginning programming I would appreciate it. I’m really having fun with the LEDS, and would like to start learning to program by writing code for LEDS, because it is very rewarding to see the code come to life so fast. Thank you in advance.

You would use the 10A power to connect to the LED + and – connections for powering the LEDs. How long are your strips? Over 1m and I recommend powering them from both ends because of voltage drop caused by the LED current draw. Or in other words hook up power to + and – at both ends of the strip. Usually a short wire to the near end and a wire slightly longer than the strip to the other end.

For the power supply just search for 5v 10A power supply on You’ll probably want a black brick style supply with a standard AC cord input(with your country’s plug) and the coaxial DC output connector. Or maybe you can find one around from some old equipment that has 5V out and somewhere between 5-10amps. I used an old Linksys router power supply for a while. npower electricity power cut The input and output voltage and current is always printed on the brick or wall box.

Yes, you can use that connector to connect the power supply to the strip solder a red(+) and black(-) wire to the strip +and – and then connect that connector with the center pin as + (red) and the barrel as – (black). If you also want to connect it to your UNO for power you would need a Y connector, or you could just run power back from the strip to the UNO using the jumpers you listed. You can also power your UNO (while you’re developing) with the USB cable. Then you would need to just connect the – (black) of the strip to a GND pin on the UNO. Use a jumper with a male pin on one end. Cut the other end off. Solder the cut off end to the strip, plug the pin end into GND on the UNO.

For jumpers I recommend the ones like you listed with the rainbow ribbon. Just tear off however many you need for connections. One at a time or as a group. I ordered a set of ( F-Female, M-Male ) F-F, M-M and M-F. The F connectors are for connecting to pins on your UNO or other boards. The M are for plugging in to connectors on your UNO or on a breadboard and the M-F make nice extension wires. I have all 30cm length because they are convenient for most prototyping.

Yep, I know about the 5 leads on each end… three are in the plug and two are apart. If you were to actually look under the shrink-wrap on the end of the strip you would find that the two wires are soldered to the same places as two of the wires in the plug. Look closely at your strip. electricity prices by country You will see three connections. +5V, Data and – GND. gas arkansas This is because you can then provide two sources for DC on the strip. In reality though, you only need to use the DATA and the ground from the plug, and couple the plugs together between the strips and then provide DC through the two other wires that are loose.

What I did was plugged the connections together in the middle and soldered the matching wires together in the middle of my strips (5M each strip) And then I connected my controller to the plug at one end. The other end of the strip I ran a pair 18ga wire to the two loose wires and provided a second feed of DC to the far end of the strip. With only 2M of LEDs you may get away with only feeding DC from one end and not have any fading at the far end, but the only way I’ve found to be sure is to light up all the LEDs and then connect DC at the far end to see if the ones at the far end get brighter.

For power and splitting the supply, you can just run a wire to the VIN pin and GND pin on the Arduino if you don’t want to mess with a plug in the DC power jack. And then run a second set of wires from the AC adapter to the LEDs to power them. That way you would only need 1 adapter for the power with the terminals on back and 2+ wires and 2- wires from the adpater to power the Arduino and the LEDs respectively.

So what i want to do is use lights as indicator and put them on a climbing wall which has no holds. I want to light up a particular number of lights on the wall depending on the distance between each two and angle. Distance and angle are different depending on the difficulty of the route that i want to create. I have measures of the average distance between holds of different difficulty levels routes. I am not sure how to proceed in terms of the hardware required and wiring it all together because i am planning on doing it in an actual climbing centre as a friend who works in one said that he can give me access to one wall which has no holds for one day. So i would like to attach lights on the wall. I want to attach a small light next to each hole and either light them up one by one by taking into account the distance and angle or light the whole route at once. I am not sure how to do it in the actual climbing centre. I was thinking of using neopixel lights and cutting them but then i have doubts on how to connect them and wire it in a wall that i can actually use. And i am not sure about the distance measurement between individual neopixels.

The neopixels should work well for you. There is no issue adding wire between the pixels. And since you only plan to have about 10 pixels lit up at any time you don’t really need to worry about current draw either. If you do plan to ever light up all the LEDs then I would recommend adding a second power feed to the far end of the run so DC power comes from both ends. It helps balance current draw. online electricity bill payment Use 18 awg wire for the second power feed.

For the initial design, I would just store pre-configured routes in the microcontroller, and not worry about angle and distance calculations. This would be a good proof-of concept and allow you to work on the calculation system over an extended period of time without worrying that the wall is not operational. Basically all you would need to do is store the LED numbers you want on in an array, and feed this array to the string lighting up the LEDs you need. It would also be cool to have the wall doing random patterns/fades/washes/etc. when it is not in use.