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1  Using Arduino / Networking, Protocols, and Devices / Re: DS1307 intermittent starting on: September 28, 2014, 10:07:45 am
Thanks dannable,   that might be a clue, but as far as I know the power never went down ( though it can ) but the backup battery should have kept it alive ?

Anyway, its on the road now,  (oddly enough heading for a wind farm in the Eastern Cape ) so I just hope there are no problems.

I don't think the 35 amphour main battery will have problems supplying the displays 24/7, even in African winter.  My sign draws about an amp in full sunlight ( there is auto dimming for overcast or night conditions, where it will drop to a few hundred milliamps or so )

The solar panel is a 40 watt unit, and charged the battery fully while being in the patio shade the last few days of testing.

see attached pic
2  Using Arduino / Networking, Protocols, and Devices / DS1307 intermittent starting on: September 27, 2014, 11:48:10 pm
I have tried a forum search on "RTC is NOT running!" but of course this is in the setup of  every sketch that members have posted, so most posts are about other issues.

I have built a safety display that tracks days since last accident, and days to next goal.

It is solar powered , and I have a DS1307 RTC so that I can update the number of days at midnight (  I know it will drift a bit, but as long as its in the middle of the night thats fine )

Should there be no sun for a couple of days and the battery goes flat, I have both target days saved in eeprom as unixdays, so it will automatically update the right number of missed days.

The guy I have built it for is collecting it this morning at 9am,  but when I got up at 4am  ( as one does on Sundays being self employed ) I saw that the days had not changed at midnight.

I took it all apart again and hooked up to the pc, and got the error message "RTC is NOT running!"

I am using the    #include "RTClib.h"  library,  and tried uploading a couple of  simple readtime examples, and each time it said the RTC wasnt running.

The battery is 2.8v still, but it had been powered all night from the battery anyway.

I then tried Nick Gammons 12c scan, and it showed me the address as 0x68.

As there is no address shown  in the code, I assume that is in the library, but when I added

#define DS1307_I2C_ADDRESS 0x68         it sprang back into life ..

I tried commenting out the line and it worked fine again, as did the simple checktime codes.

I have left the line in there now, and if it wasnt for the fact that the guy has driven 1000 km to Cape Town for the weekend  and going home today, I would have bought another chip and crystal on Monday.

Has anyone had a similar experience?  and will that extra line be OK?  

Code attached
3  Using Arduino / Programming Questions / Re: Why the L ? in 86400L for instance ( days from Unixtime ) on: September 22, 2014, 02:01:57 am
Thanks guys,

I want to actually study this stuff when I get caught up, but I have been working 14 - 18 hours a day since Christmas ( which is why I havn't been on the forum for a while ) but soon I hope, I can study it a bit and fill in all these many missing gaps of knlowledge .
4  Using Arduino / Programming Questions / Why the L ? in 86400L for instance ( days from Unixtime ) on: September 21, 2014, 10:45:47 pm
I must have missed this somewhere, and I have tried searching the forum.

I am building a display that is updated every day at midnight, using a simple RTC for timing ( it has to run for weeks )

To test it without waiting for a whole day  each time, I thought I could change the / 86400 for getting days from Unixseconds to say 864, and make it advance 100 times a day .

I dont know why there is the L after the divisor, so can I just use  ?      
int rxday = now.unixtime() / 864L;

Well I tried that and it is working, refreshing every 14.4 minutes, so perhaps the L forces it to a long integer ??
5  Using Arduino / Networking, Protocols, and Devices / Re: 433Mhz Modul with Virtual Wire | NRF24l01+ with Mirf/NRF24 didn't working on: September 21, 2014, 03:54:30 am
I use the simple Hope 433 Mhz tx and rx modules, and I connect the +5 of the transmitter to the PTT pin of the 328 ( to save even more battery power ) and the data to the nominated  data pin.

You have to set which pin is which in setup, and the baudrate of the VW link has to be the same each end of course.

Also you cant use pin 9 or 10 for pwm if you are running VirtualWire.
6  Community / Bar Sport / Re: How many times is someone not replying after asking question ? on: August 27, 2014, 02:39:46 am

one definition of ASKHOLE :-

Someone who wastes other people's time by posting questions on discussion forums when the answer is only a Google search away - or answered many times previously.
7  Community / Bar Sport / Re: searching for a robotic (arm) project? have a look at this! on: July 18, 2014, 04:03:26 pm
Quick enough for fencing Bob ?   :-)
8  Using Arduino / LEDs and Multiplexing / Double the output, ( or viewing angle ) , same current , half work for a MAX7219 on: June 20, 2014, 10:50:12 am
I have tried a search on this subject, but quite honestly the forum is so big now, that it takes ages to sift through the threads bought up.  This might be old hash .

Let me just run this past you guys....

I made a soccer scoreboard with 7x5 displays last year , Using the SAA1064 chip , which gave a 50% duty cycle , for max output from each LED.
I am now making some more boards using the MAX7219 driver.

I have arranged it this time with 5 columns across and 7 high .

This means I can set up in the register to limit to 5 columns, and skip the other 3, giving more brightness ,  20 % duty cycle, but still down on the 50% duty cycle of last years

The LEDs I am using this year are more than twice the output of last years ones, so I should be back on track with the actual  apparent brightness of last years project.

Now I have a request for a similar sign twice the digit size  ( 4 times the area ) but I have realised that I can put 2 red LEDS in series in place of the previous one ( each has 1v9 voltage drop ) and the chip should be able to supply Imax to both LEDs in series at 3v9

So in theory I can get twice the light output per column, using twice the number of LEDs, with the chip now running cooler, as it doesn't have to get rid of the extra ( 5 - 1.9 v )

But since  now I am saving the power dissipation in the chip, perhaps I can pulse the LEDs with twice the current as before ?  Giving me twice the light output for the same digit ?  ( OK at double the supply current, but there is no such thing as a free meal ! )

How does this sound ?

If you are not upsizing, you could tilt every other LED by half the viewing angle and get the same intensity as with one LED.

9  Using Arduino / Project Guidance / Re: bytes and nibbles on: June 16, 2014, 11:27:38 am
Too true.
10  Using Arduino / Project Guidance / Re: bytes and nibbles on: June 16, 2014, 10:13:48 am
Ans some tired old guys in the middle of the night still get them transposed  ,,,,   :-)
11  Using Arduino / Project Guidance / Re: bytes and nibbles on: June 16, 2014, 09:51:33 am
This thread shows absolutely the advantage of the Arduino community, I made a stupid mistake that my Great Grandson would not have typed , and instead of wasting a whole day finding it, you guys picked it up.

I am not interested in trying raspberries or whatever, I have had so much support ( even though I am still stuck in V22 until I can find a few hours to upgrade  my libraries to V1.05 )  and its working for me, who didn't have a clue about micros 3 years ago ( at 63 )
12  Using Arduino / Project Guidance / Re: bytes and nibbles on: June 16, 2014, 08:45:01 am
Not quite , more like  "  Ah, So "  :-)

13  Using Arduino / Project Guidance / Re: bytes and nibbles on: June 16, 2014, 07:50:15 am
Yes thanks, I had just spotted it and called myself a name that my wife often hears :-)

Thanks Guys
14  Using Arduino / Project Guidance / bytes and nibbles on: June 16, 2014, 07:22:57 am
I am busy just trying to put together some building blocks for my next sketch, and I keep tripping over this confusion on my part.  The top code works fine to display a 7x5 matrix character :-
   byte displayArrayA[5] = {63,63,136,72,72};
So I thought I would tidy it up by having a variable for the 0 -4 in each line :-

for (x=o; x<=4; x++ ) { 

But it tells me I am trying to convert an integer  to a byte or a byte to a byte, or whatever, I have tried all the religions when declaring the x , but am getting confused again.
I have searched and somebody had a similar hassle but it was to do with pointers that I havnt come across yet.

Feel free to tell me I am missing the obvious again.
15  Using Arduino / Project Guidance / Re: 7 changes to 0 on only 1 BCD switch SOLVED on: June 08, 2014, 03:17:02 am
sometime during debugging another hassle, I commented out line 2 here

 Serial.println("TX setup");              // for debug only
  // vw_set_rx_pin(0);
  vw_set_tx_pin(9);    //  Tx module connections and speed
  vw_set_ptt_pin(13); // powers Tx and LED

I must have added that at some previous time when I had a problem, but uncommenting solved it.

default pin for rx even if you are only using a transmittter is 11,  and I am using that to scan F,   so I guess the VW makes it an input.

Thanks for your time guys.
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