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In short, I'm trying to connect an NRF24L01 module and an SD card writer to the same Arduino, so I can receive data via the NRF and write it to the SD card. And the SD card writer is screwing up the SPI interface. As soon as I plug in the SD card's MISO line, the NRF stops receiving and goes crazy spitting out blank lines.

This seems to be a known problem, from what I've been reading up on this forum. But all the threads I've seen discuss the issue, and in the end don't really get anywhere.

Anyone got a definitive solution to this problem, to get these two to work together? In my case, I've got the SD card working perfectly on its own, the NRF working perfectly on it's own, even a DS1302 module working perfectly on its own. And I've got the NRF + DS1302 working perfectly together. But when the SD card comes into play, everything blows up.

Using an Arduino Uno, with the standard NRF and SD libraries everyone else uses.
Is the leaderboard online or local? If it is local, just store the top 10 scores in the Arduino's EEPROM. Just Google what EEPROM is and there are many tutorials on how to do this. If the leaderboard is online, things will be much more complicated because you will need somewhere to store the scores.
Project Guidance / Re: Blynk vs power outages
Last post by Wawa - Today at 05:09 am
I tried using latching relay but apparently when the power comes back it's sends a little pulse that resets the latching relay just like a regular relay.
Well, that would depend on the code.
A relay shouldn't turn on by itself on power-up.
Project Guidance / Not sure where to start search...
Last post by SueF - Today at 05:07 am
Hi, I'm brand new to Arduino, but not brand new to programming.  Could I please get some help on where I should even start looking for advice on what I want to do...

I have an Arduino programme written by a friend, displaying a reaction time, linked to a set of traffic lights.  When the light turns green, put your foot down on the accelerator and your reaction time is displayed on the read out.  That bit has already been done (Thanks Pete).  What I would like to do now is record everyone's time and display a leaderboard (in real time) of the fastest reaction times to the slowest.  Perhaps we could use a barcode / reader to associate a name with a time?

Thanks in advance, and sorry if this is not the correct place to ask this, but I've spent some time looking around, and I think this is feasible, but I really just don't know where to even start investigating.
Hey guys, I am extremely new to this and just needed some clarification. So I am planning on using an arduino to conduct a simple test, measure the load from two different motors via two load cells. Now to make it complicated. I was planning on having a barometric sensor start the motor and to start recording data from the load cell (to save space in the sd card).
At the worst, you get stuck waiting for a bit between questions until you have made 100 posts. This is a spam prevention feature of the forum.
Project Guidance / Re: Capacitive proximity
Last post by Ralph2694 - Today at 04:55 am
Can you please tell me how?... Because i tried using touch plate and 555 astable multivibrator circuit by detecting the frequency variation so can you give me a circuit!!
Thanks Robin2, I will use the correct photo format next time.

Also thanks WattsThat - I think the details of my wiring are lost in the photo.. it is definitely wired as in the diagram.

But the good news is.... I've solved it!!!!  I had to add a cap on my motor board to connect the 5V and EN pins!! Now it works perfectly.  I have no idea why this worked.. I also don't know how I killed 3 boards in the process, but it seems to be ok now. 

Thanks for your time!!
Oh thanks, i guess that answered that. What happens if i have more questions than i can post?
You might find the codes you need on the LIRC site.

FWIW I also have an LG TV and for my project used the codes found on that site.   I wrote a header file with the following:

Code: [Select]

const long  PRE_DATA = 0x20df0000;    // prefix for remote command

enum COMMAND {

int tv_codes[] = {
                    0x02FD,       // up
                    0x827D,       // down
                    0xE01F,       // left
                    0x609F,       // right
                    0x22DD        // ok


Commands are sent to the TV with the function:

Code: [Select]

 Send passed commend to IR reciever.
void sendCmd(COMMAND cmd)
  // combine pre data with specific code
  irsend.sendNEC(PRE_DATA | (long)(tv_codes[cmd] & 0xffff),32);

  // we must move deliberately to avoid missed clicks


which is called, for example, like this:

Code: [Select]


Thank you very much! That is exactly what I was looking for.
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