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931  Community / Bar Sport / Re: Ardunio C++ conversation!!!! on: August 16, 2012, 02:06:37 am
The bottom line is that with no knowledge of any of the things that Gooby is talking about, ( lithp etc ) a 64 year old absolute newbie like me can quickly write extremely satisfying software for all sorts of projects.

Arduino ( using ,as it happens C++ ) worked for me !   and presumably the other newbies amongst the 142512 members of this forum ?
932  Using Arduino / Project Guidance / Re: serial to PC instead of SD card logging - Sorted on: August 12, 2012, 03:33:01 am
Ok its working well,  setup Newsoftserial for tx and rx, and it runs fine on port1 ( or my serial/USB adaptor I forgot I boght a while ago )

The data logging software on MegunoLink is very good, you can even draw graphs realtime on your PC from data from the Arduino. I am going to make a donation for the software.

Mine is a stand alone project that I am making for someone upcountry, so I must work out if I can send them a copy of the MegunoLink software, plus  AVRdude ( which it needs ) rather than the whole Arduino program ...
933  Using Arduino / Project Guidance / Re: serial to PC instead of SD card logging on: August 11, 2012, 06:30:32 am
The ftdi cables are expensive here, and I am sending the complete prototype unit to a friend upcountry, so if they have a simple terminal program ( like MegunoLink ) and set it for 9600 and no handshaking .will they be ok with just my sending a string via the TXD to the PCs RXD in ( at the right level ? )

It will generally only be a couple of times a minute I guess.

Presumably they can either check for serial in every loop ?

PS   John Boxall in his excellent Tronixstuff course suggests using MegunoLink as a data logger instead of the SD Card ( obviously if there is a PC handy )
934  Community / Bar Sport / Re: OMG ! I am a God Member ! on: August 11, 2012, 05:59:12 am
I agree too, congrats NI$HANT but it gets a bit hard for an old fart like me to rank our heros like Tesla etc in any order ( and some I must confess I dont remember :-)
935  Using Arduino / Project Guidance / Re: serial to PC instead of SD card logging on: August 10, 2012, 04:32:58 pm
I am not using the Arduino for the project, just the 386 on a minimum pcb, so USB would be a bit more complicated than a simple MAX232 chip to connect to the monitoring PC ?
936  Using Arduino / Project Guidance / Re: COMPLETELY NEW user of Arduino/electronics/etc on: August 10, 2012, 04:17:35 pm
If you have strings of say 5 LEDs in series running off a 12v supply, the voltage across them ( for red LEDs ) will be about 9.5 volts, and  you could use a  120  ohm resistor to limit their current to about 20 mA  (  12v supply , minus the 9.5v across all the LEDs  =  2.5 volts / 0.02 amps  ( ohms law ) = 125 Ohms )

BUT  this only applies if the 12 volts is regulated , if the supply is taken directly from the car battery it can go up to 14 volts, giving you ( 14 - 9.5v   =   4.5 / 120 ohms  = )  37 mA through all the LEDs which will release their magic smoke, or make them go dark :-)

I always use a 12v regulator for every 1 amp bank of LEDs displays.  ( and I only run the LEDs at 18mA which I find a reliable level - out of the last 50,000 LEDs in 3 years I have only had about 6 LEDs fail - excluding orange ones which I had bad luck with for some reason ! )
937  Using Arduino / Project Guidance / Re: serial to PC instead of SD card logging on: August 10, 2012, 02:58:50 pm
Thanks Wanderson,   very interesteing about the packet size for saving on SD cards,   I will try that on another project I have that uses cards.

Now its up and running, I see this project needs the realtime data to a screen.

I am using the 328 chips on small pcbs ( I just use the Arduino for testing and programming )  and the RXD pin of this logger unit I am using to receive from the 2.4GHz receiver, (  I could change that to a SoftSerial pair of pins )

If I have a D9 serial connector, do I need to connect more than TXD and ground ?  ( I am not sure about the RTS and CTS etc pins )
938  Using Arduino / Project Guidance / serial to PC instead of SD card logging on: August 10, 2012, 11:04:44 am
My queueing project is working, recording data from 7 units via wireless links.

I am not happy with the SD card reader for logging , partly becuse I think the time it takes to write each time is making it miss some of the incoming data, and partly because there is no realtime info.

I want to change it to a simpler system that outputs a serial CSV string to a PC via a RS232 serial link, every time a button is pressed.

I am just learning about Serial comms.

Can I just use TXD and RXD through a MAX232 level converter to a 9pin serial connector ?

In fact can I just use the TXD  ( I want to use the RXD for one of the radio link inputs )

Just need a bit of guidance before I fire up the soldering iron...
939  Using Arduino / Project Guidance / Re: Money Slot detector (IR / combining analog inputs) on: August 10, 2012, 10:27:05 am
You could have a line of LEDs illuminating a load of cheap LDRs connected in series.

If you use white LEDs rather than IR,  it would light up the slot ?

The top LDR is connected to Vcc  ( 5v ) and the bottom one to a 220k preset pot that goes to ground.

With nothing breaking the beam ( all the LDRs at low resistance ) set the preset so that the voltage at the bottom of the LDRs is 2.5v

Connect this point to one of the analog inputs of the Atmega 328 - or arduino board -  with a 100 nF capacitor to ground to smooth out any noise.

With you thinnest bank note in the way ( which should weaken several of the beams ) measure the voltage on the analog pin, and write your sketch to detect an object if the voltage drops below this level ( leave a margin spare for ambient light noise )

The idea is that with all the LDRs illuminated, ( say there are 10 of them with 3 kOhm resistance  illuminated ) , the total resistance will be 30k.
As soon as even one of the LDRs is shaded, it goes up to perhaps 100k resistance, making a series resistance of 127k,  more than enough to detect.
940  Community / Bar Sport / Re: Ardunio C++ ROCKS ! on: August 04, 2012, 02:36:35 pm
941  Community / Bar Sport / Re: Ardunio C++ SUCKS!!!! on: August 04, 2012, 10:19:29 am
Very interesting Michael,

and frightening,  I am so glad now that I never volounteered for a shuttle flight !
942  Community / Bar Sport / Re: OMG ! I am a God Member ! on: August 04, 2012, 08:20:41 am
Thanks guys, I hope to have a bit more time for the forum soon ( got 4 simultaneous orders out this week, after 2 months without a day off )

My next project is going to be a wireless mesh thingy, using the SIM20 modules.  I bought a couple, but the technical info is attrocious, so I will experiment and see.

No doubt I will be " phoning a friend" again on the forum !
943  Community / Bar Sport / Re: Ardunio C++ SUCKS!!!! on: August 04, 2012, 08:17:05 am
I was working at a NASA tracking station in the UK when I did a ( 2 days )familiarisation  course  in Fortran ( 1968  )
I assume we were using it for satellite predictions ...
944  Community / Bar Sport / Re: Ardunio C++ SUCKS!!!! on: August 04, 2012, 08:13:31 am
Είμαι βέβαιος Arduino είναι εξίσου εύκολο στην ελληνική γλώσσα  !
945  Community / Bar Sport / Re: Ardunio C++ SUCKS!!!! on: August 03, 2012, 05:16:36 pm
Thats great, perhaps you could get to adding some help for newbies from the same background experience ?

When I get a chance, I want to post a couple of things for techies from my " soldering iron" background , explaining why pin2 is actually pin 4, and pin 28 can be analog 5 or digital 19 ( took me a while ) and so on.
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