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Topic: I need help  (Read 1 time) previous topic - next topic


the resistors where do i need to place them on the board ?
Maybe it is your language problem, your English is certainly better than my German ( I can order three large beers ) but you only need 1 resistor when driving any number of WS2812 chips. See this link:- https://learn.adafruit.com/adafruit-neopixel-uberguide/basic-connections

20* 330 ohms resisters
1 * 330 ohms resister


Note that I have not seen much discussion about how this project will actually be constructed.

An Arduino UNO or clone thereof, is a very inconvenient format to which to connect things.  Unless you are using a "shield" which plugs directly into it, which has not been mentioned so far, the "Nano" is a far more practical version to use.

It is functionally (and in programming) almost identical to the UNO - the differences will never be relevant in the vast majority of uses - and it comes with "header pins" either ready to be soldered to its connection pads or already soldered in place, allowing it to be plugged into a "solderless breadboard" for prototyping or soldered to "stripboard" or a purpose-designed PCB or "perfboard".

The UNO cannot readily be mounted to any of these due to having sockets fitted rather than plug pins and an odd arrangement of its sockets.  If you seriously wish to use a UNO, you will want a "sensor shield" to go with it - but the Nano is really much more practical (and there are sensor shields to go with it as well).


Jun 30, 2019, 02:15 pm Last Edit: Jun 30, 2019, 02:16 pm by ledgirl8089
Ok so hello again, I received everything (all the parts)

Now I needs help, I tried doing it by myself and it was a disaster, I really needs some help with assembly and also with coding just direction and I will do the rest.

Here is the ideal of what I want.

I have 20 addressable lads that I want to connect each one to a hall sensor, after that I want to be able to run the pen (attached in the photos) with the metal ball over the hall sensor and make it turn on.

Do you guys think its possible?



here is the photo


one more photo


Right then.

Twenty WS2812 LEDs.  Are you going to use them as a strip, or do you propose to cut some and connect the pieces?  I don't think we mentioned this, but you must be able - equipment and skill - to solder electronic parts.  This is not negotiable, but if you are not familiar with this, there arguably should be someone locally - such as an Amateur Radio operator ("Ham") - who can teach you.

I did advise to use an Arduino Nano rather than the UNO.  Whichever you have, you will require some structural materials to make the connections, a "solderless breadboard" would be OK for development purposes, and then "stripboard" or a "perfboard" version for final assembly.

And wire.  :smiley-eek:

And for your purpose, PCF8575 expanders - readily available - would be better than PCF8574 (as they each give 16 I/O pins).

20 WS2812 LEDs if fully illuminated to white, will draw 20 x 60 mA = 1.2 Amps.  To allow for comfortable use, you would be looking for a "Phone charger" as a 5 V regulated power supply, rated at 2.1 A - which is nowadays, quite common.  While you can power the Arduino via the USB port, you cannot then take 2.1 A from the "5V" pin, so you will need to connect the 5 V (and always, ground) in parallel to the LED strip and Hall sensors.

Now as we have advised more than once, your task is to assemble and test one part at a time.  Given that you have the LED strip, I think that would be a reasonable one to start with.  You have not shown whether this strip comes with leads already wired to it.

Incidentally, you should now understand that this will take some considerable time to do.  It would take me considerable time and it really is going to take you a fair bit more.  (Of course, I have a full-time job, but I expect you have a fair bit of study to occupy your time as well.  :smiley-lol: )  So it may be quite sensible to buy more appropriate parts and those which you have not yet thought of,  even if there is a little wait involved.

So let's understand that this will involve a lot of steps and discussions back-and-forth.

Adding that other photograph now ...

Ah!  You have some of the parts.  Unfortunately, a UNO, but just a mild impediment.

OK, what have you done so far?  Post your code - according the the instructions, item 7.


ok so i do have the nano also (attached a photo) also i pretty good in soldering (attached a photo) :) now what how do i need to connect them because i tried googling this and its not working there are tons of videos on youtube but i could not understand them because they are talking about difference situations and parts.

is there anyway to see somewhere a plan like the attached photo?  


OK so I do have the Nano also (attached a photo)
I see not a Nano, but a Pro Mini and adapter which effectively makes up a Nano.

also I pretty good in soldering (attached a photo)
Good!   :smiley-cool:

now what how do I need to connect them because I tried googling this and its not working there are tons of videos on YouTube but I could not understand them because they are talking about difference situations and parts.
Well, the first thing is as I said, to approach one part of the project - perhaps using the LEDs with the Adafruit library to show pretty patterns and control them individually.

is there anyway to see somewhere a plan like the attached photo?  
You show one NeoPixel (WS2812) connected to the UNO.  That is a start, so what have you done with that?


Since you are having the magnet drag a metal ball, you could build a track for the ball that has contact pads along it, and use the ball itself to make the connection between the pads to indicate its position along the track.  Simple way would be to have one side of the track lined with a foil strip connected to ground, and on the opposite side of the track have 20 short sections of foil connected to 20 inputs... 
There is a way to reduce the number of inputs required, and at the same time enable a higher number of contacts. Have two short contact lengths of copper tape at each 'switch' point, called RIGHT and LEFT. These contacts will be close together. Every RIGHT will be connected to a digital input, and every LEFT to another. Thus a RIGHT input followed closely by a LEFT input means the ball is going in one direction (say left), and conversely a Left-Right combination means the ball is going Right. The code would then increment or decrement the ball's location as each set of switches was negotiated, and occasional extra contacts would resynchronise the position of the ball to a known position.

Hope this helps.

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