HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Jun 14, 2012, 08:43 PM
Registered User
PMB-NZ's Avatar
Wellington, New Zealand
Joined Aug 2009
186 Posts
I have used the LS20031 which is in the same series. It's safest to use a level converter but the TX on the GPS can directly drive the RX on the arduino CPU. You should put a voltage divider (2 resistors) between the Arduino TX and the GPS RX to reduce the maximum voltage it sees from the arduino. The LS20031 needs 3.3V supply, which is why I haven't flown it yet. I used the Arduino serial monitor to send the commands to the GPS to set it up.

Paul
PMB-NZ is offline Find More Posts by PMB-NZ
Last edited by PMB-NZ; Jun 14, 2012 at 08:43 PM. Reason: typo
Reply With Quote
Sign up now
to remove ads between posts
Old Jun 14, 2012, 10:17 PM
Registered User
United States, ID, Fruitland
Joined Apr 2008
32 Posts
I used the LS20031 as well and posted a few board designs.

Page 57 of this thread has the schematic and board layout for using an Arduino Pro Mini without the LM1881.

Page 61 of this thread has the schematic for an Arduino Pro Mini using the LM1881.

Page 65 has the third board layout I made which is smaller than the previous two.

All three boards use a logic level converter from SparkFun.com to allow your Arduino running at 5v communicate with your GPS running on 3.3v

You'll also need a 3.3v Regulator and an LM1881.

The full (hand drawn) schematics for the boards are in the posts listed above as well as board layouts that can be printed onto overhead transparencies for etching your board.

If you have any questions about any of it, let me know.
vasago17 is offline Find More Posts by vasago17
Reply With Quote
Old Jun 15, 2012, 12:16 AM
Registered User
El_Nono's Avatar
Buenos Aires
Joined Jun 2008
39 Posts
Hello Friends

I did not like the characters make some changes so great. Since I was, I made some other changes.
Hope you like.

I'm still working.

El Nono
www.fpv-argentina.com
El_Nono is offline Find More Posts by El_Nono
Reply With Quote
Old Jun 15, 2012, 12:07 PM
Just another user
Dennis Frie's Avatar
Denmark, Capital Region of Denmark, Naerum
Joined Feb 2011
1,081 Posts
Quote:
Originally Posted by El_Nono View Post
Hello Friends

I did not like the characters make some changes so great. Since I was, I made some other changes.
Hope you like.

I'm still working.

El Nono
www.fpv-argentina.com
Looks very good, great work.
Dennis Frie is offline Find More Posts by Dennis Frie
Reply With Quote
Old Jun 15, 2012, 03:57 PM
ary
Registered User
Argentina, CB, Córdoba
Joined May 2012
17 Posts
Thanks PMB-NZ and vasago17. I'll use a voltage divider.

5v Arduino 3.3v serial
GND ---------------- GND
RX ------------------ Tx
Tx ---1K8----3K3-- GND
..................|
.................Rx
ary is offline Find More Posts by ary
Reply With Quote
Old Jun 15, 2012, 03:59 PM
Just another user
Dennis Frie's Avatar
Denmark, Capital Region of Denmark, Naerum
Joined Feb 2011
1,081 Posts
Quote:
Originally Posted by ary View Post
5v Arduino 3.3v serial
GND ---------------- GND
RX ------------------ Tx
Tx ---1K8----3K3-- GND
|
--------- Rx
Just give it a shot with 3.3 volt and no further changes - I have used 3.3 volt logic devices with 5 volt Arduino without problems quite a few times.
Dennis Frie is offline Find More Posts by Dennis Frie
Reply With Quote
Old Jun 15, 2012, 04:04 PM
ary
Registered User
Argentina, CB, Córdoba
Joined May 2012
17 Posts
Quote:
Originally Posted by Dennis Frie View Post
Just give it a shot with 3.3 volt and no further changes - I have used 3.3 volt logic devices with 5 volt Arduino without problems quite a few times.
But... can I damage my GPS module? It works with 3.3 TTL. When Arduino writes in the TX it will write using logic at 5v. Is it a problem for my GPS?
ary is offline Find More Posts by ary
Reply With Quote
Old Jun 15, 2012, 04:07 PM
Just another user
Dennis Frie's Avatar
Denmark, Capital Region of Denmark, Naerum
Joined Feb 2011
1,081 Posts
Quote:
Originally Posted by ary View Post
But... can I damage my GPS module? It works with 3.3 TTL. When Arduino writes in the TX it will write using logic at 5v. Is it a problem for my GPS?
I doubt it, but I can't guarantee anything
You can use a simple voltage-divider if you like (perhaps that was what you tried to draw?)
Dennis Frie is offline Find More Posts by Dennis Frie
Reply With Quote
Old Jun 15, 2012, 04:10 PM
Registered User
Basel, Switzerland
Joined Mar 2008
93 Posts
it can be a problem. if you want to be minimalistic, you can add a resistor in series (1k or so, no important). the protection diode at the input, together with the resistor will bring the voltage down. voltage divider is fine too.

if you have several 3.3v devices, the atmega runs happily at 3.3v too, even at 16mhz.

dennis, can you uplaod your usart code?
quix-fz is offline Find More Posts by quix-fz
Reply With Quote
Old Jun 15, 2012, 04:12 PM
ary
Registered User
Argentina, CB, Córdoba
Joined May 2012
17 Posts
Quote:
Originally Posted by Dennis Frie View Post
I doubt it, but I can't guarantee anything
You can use a simple voltage-divider if you like (perhaps that was what you tried to draw?)
yeap! Thanks Dennis

As I see you online, I wanna ask you how to remove the dark background in the prints. I'm using your code version 0.18
ary is offline Find More Posts by ary
Reply With Quote
Old Jun 15, 2012, 04:15 PM
Registered User
Basel, Switzerland
Joined Mar 2008
93 Posts
Quote:
Originally Posted by ary View Post
how to remove the dark background in the prints. I'm using your code version 0.18
you can use a bigger resistor (the one from atmega directly to video, without diode), or remove it completely, or only remove it in software in the code.

i'm using 47ohm
quix-fz is offline Find More Posts by quix-fz
Reply With Quote
Old Jun 15, 2012, 04:21 PM
ary
Registered User
Argentina, CB, Córdoba
Joined May 2012
17 Posts
Quote:
Originally Posted by quix-fz View Post
it can be a problem. if you want to be minimalistic, you can add a resistor in series (1k or so, no important). the protection diode at the input, together with the resistor will bring the voltage down. voltage divider is fine too.
Arduino TX -->R1K--->Diode--->RXGPS

is it ok?
ary is offline Find More Posts by ary
Reply With Quote
Old Jun 15, 2012, 04:22 PM
ary
Registered User
Argentina, CB, Córdoba
Joined May 2012
17 Posts
Quote:
Originally Posted by quix-fz View Post
it can be a problem. if you want to be minimalistic, you can add a resistor in series (1k or so, no important). the protection diode at the input, together with the resistor will bring the voltage down. voltage divider is fine too.
Arduino TX -->R1K--->Diode--->RXGPS

is it ok?
ary is offline Find More Posts by ary
Reply With Quote
Old Jun 15, 2012, 04:27 PM
Registered User
Basel, Switzerland
Joined Mar 2008
93 Posts
Quote:
Originally Posted by ary View Post
Arduino TX -->R1K--->Diode--->RXGPS

is it ok?
hehe, i meant the protection diode inside the gps, you can leave that diode out. the resistor alone is enough
quix-fz is offline Find More Posts by quix-fz
Reply With Quote
Old Jun 15, 2012, 04:35 PM
ary
Registered User
Argentina, CB, Córdoba
Joined May 2012
17 Posts
Thanks quix-fz for your support!

And related to the dark background in the text... did you mean to use a bigger resistor at the output of the Arduino PIN11? Nowadays I'm using 120ohm.
ary is offline Find More Posts by ary
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion Diy osd karl k FPV Talk 2 May 03, 2011 01:31 AM
Idea New DIY OSD? atari7202 FPV Talk 1 Mar 25, 2011 01:08 AM
Discussion see my own diy OSD video Passion Aerial Photography 7 May 27, 2010 02:28 AM
Discussion REAL homebrew DIY OSD - Check it out! jafoca FPV Talk 8 Jun 29, 2009 07:52 PM
Discussion picoOSD DIY PIC12F683 based OSD in C kbosak FPV Talk 6 Jan 31, 2008 08:47 AM