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Old May 05, 2008, 09:34 PM
Electronic Hobbist
weber_alejandro's Avatar
Mendoza, Argentina
Joined Jul 2007
32 Posts
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7 Channels PIC16F876 PPM encoder

Hi guys, this is my almost final version of a 7 Ch PIC16F876 PPM encoder. Is working and have this features:

7 channels
5 analog proportionals (5th from extra pot)
2 on/off (1ms to 2ms digital jump)
2 switchs to activate/deactivate Dual Rate on channels 1 and 2 (alerons and elevator)
The control sticks are calibrated from menu
Has 5 memory registers to setup this:
% de Dual Rate for each channel
Channel inversion
Channel trim
Chanel end points, both max and min
PPM signal normal or inverted


The circuit is very simple, the supply is 5v from a 7805 voltage regulator. The signal from control sticks is amplified in LM324 to improve the level to the A/D conversor of 10 Bits. The 5th channel is not amplified becouse the signal change from 0v to 5v in 300 (normal pot)



The stick pot only moves 60 of 300, and the voltage across only change from 0 to 1v, that is the reason of amplification with LM324.

The other periphericals are switchs of digital channels, dual rates, setup buttons, a 16x2 display and a "piezo buzzer".






Display circuit:


Some setup screens:
Configuring max and min reading from AD to later calculations

Channel inversion

PPM direction


Code:
BOM
Capacitors
C1       220n  
C2       0.1uF
C3       0.1uF
C4       0.1 
C5       220n   
C6       220n  
C7       18pF 
C8       18pF 
C9       220n

Semiconductors
D1       1N4148
IC1      LM324   
IC2      7805 (1A) 
IC3      PIC16F876
T1       BC547 o BC548 or similar NPN (CBE)

Miscelanious
LED1     Green
Q1(cristal)  20MHz 
SG1      Piezo Buzzer 

Resistors (5%)
R1       1K        
R3       1K       
R5       47K     
R7       1K     
R9       1K    
R11      47K  
R12      1K  
R14      10K           
R15      1K           
R16      10K         
R17      560        
R18      10K       
R19      10K      
R21      1K      
R22      10K    
R23      10K   
R24      10K  
R25      10K 
R26      10K           
R27      1K           
R29      47K         
R31      1K         
R32      1K        
R34      1K       
R37      47K     
R39	 10K

Trimpots (mini)
R6       1K            
R13      1K           
R30      1K          
R38      1K         

Channel Pots
R2       1K     (1k trims)
R4       5K      
R8       1K       
R10      5K        
R20      1K         
R28      5K          
R33      1K           
R35      10K            chasis channel(CH5)
R36      5K    

Switchs
S1       Reset          Microswitch
S2       Pulsa1         Button
S3       CH7            
S4       CH6            
S5       DualRate4      
S6       DualRate3      
S7       DualRate2     
S8       DualRate1     
S9  	 Pulsa2		Button
Some pics of the planes I fly with ths encoder:
.46 trainer

Nemo, electric


Me =) and the encoder (old version without display):

My home site
http://www.e-radiocontrol.com.ar/
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Old May 06, 2008, 06:57 AM
Registered User
Manila, Philippines
Joined Jul 2004
1,199 Posts
Thats Amazing works........Thanks for Sharing.

I use 16F877 in all my pic project.
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Old May 06, 2008, 07:23 AM
Electronic Hobbist
weber_alejandro's Avatar
Mendoza, Argentina
Joined Jul 2007
32 Posts
with 16F876 I run out of memory EEPROM (data and programm) and RAM. For example, the memory channels names 1, 2, 3 etc.... can't put a name like "trainer 1" on it from setup because this.

Maybe in future versions use a PIC 18F family or a I2C memory.

greetings from Argentina
PS: Sorry for my bad english
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Old May 06, 2008, 09:00 AM
"MAYONNAISE"
Acetronics's Avatar
Le Treport, France
Joined Jun 2004
1,392 Posts
Hi, Alexandro

really nice work !!!

worth a "parilla" fiesta !!!

I'll hold high my mate in your honor ...

Alain
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Old May 06, 2008, 08:02 PM
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meteor's Avatar
Ontario, Canada
Joined Nov 2002
1,568 Posts
Very impressive project, must have been a satisfying challenge to complete.


But, I'm a little confused... Why replicate what is readily available for very little money?

It seems that a garden-variety transmitter project is a lot of effort that could have been used for some other more unique challenge like an autopilot, or data recorder, etc.


Great work, regardless.
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Old May 06, 2008, 08:40 PM
Inciting Riots
village_idiot's Avatar
Joined Dec 2006
9,682 Posts
Because choice is good!

Also you should talk to Gordon Anderson about his Microstar2000 encoder, instead of working on new ground helping to work on the Microstar might be a good thing. His site is at http://mstar2k.com It's a PIC 18 based design.

And anyway, really good work!
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Old May 06, 2008, 11:39 PM
Registered User
Manila, Philippines
Joined Jul 2004
1,199 Posts
I just wonder why do the Most Expensive Transmitter such as Futaba 14MZ cost more than USD 2000, still using the old mechanical Potentiometer, they just added a Ball Bearing.

I was hoping they use different sensor for positioning such as Magnetic , Optical, or CCD.......You would amaze that the more than 10 year old Microsoft Joysticks uses an CCD sensor to detect its Positioning.

One of this day, I will Build this Home-Made transmitter made by Alejandro or MSTAR2000.........I know, its really more expensive to build your own......but its the Pride and Joy, when you tell your RC Buddy friend.....it my home-made transmitter......Just like in the old days, I my Scratch Build Plane.

One Nice things about Alejandro designed, is it uses a very common electronics components, which is available anywhere, even the Circuit Board is Single Side easy to made .

Please Keep us Posted on your Next project.

Ellion
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Old May 07, 2008, 12:09 AM
sahil
INDIA,HYDERABAD
Joined Aug 2005
173 Posts
great work n thanks for sharing with us

u have a very good site with complete info from tx rx to coders cool

sahil
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Old May 07, 2008, 04:13 AM
Registered User
Manila, Philippines
Joined Jul 2004
1,199 Posts
Guys, One Nice things about this Home-Made Pic controller Transmitter, You can Customized your own Mixing....its very easy to Reprogram it.

Been Thinking of Making my own HELI-CHAIR, Instead of Hacking an Expensive Futaba Transmitter, I could use this Alejandro's Pic RC Encoder.

here is the website for Heli-Chair......this is use for learning to fly a Real Helicopter:
http://www.heli-chair.com/

Alejandro, What Kind of Development Tool do you use, Have download your files, but when I tried to read it using Windows Notepad. it can not read properly, I can see the text but the format is not right.....maybe I need to use your Development tools to read the Source code.

Thanks

Ellion
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Last edited by lazy-b; May 07, 2008 at 04:43 AM.
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Old May 07, 2008, 08:42 AM
Don L.
Old Lyme, Connecticut
Joined Feb 2006
922 Posts
Quote:
Originally Posted by meteor
... Why replicate what is readily available for very little money?

Great work, regardless.
Because you don't have to reverse engineer it to get the schematic or part numbers.

Super job, Alejandro!
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Old May 07, 2008, 06:10 PM
Electronic Hobbist
weber_alejandro's Avatar
Mendoza, Argentina
Joined Jul 2007
32 Posts
Quote:
Originally Posted by lazy-b
Alejandro, What Kind of Development Tool do you use, Have download your files, but when I tried to read it using Windows Notepad. it can not read properly, I can see the text but the format is not right.....maybe I need to use your Development tools to read the Source code.

Thanks

Ellion
Hi Ellion, I use to program C and for compiling CCS running emulated in wine (I use Debian Linux). The files can be open with any text processor after decompression. To recompiling you need a C compiler for PICs, after this, you can use your best PIC programmer to load the HEX file into the PIC data memory as usual.

By the way, that chair is awsome!. Imagine you can use a little wireless camera and a monitor over the chair for more virtual reality heli flight!
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Old May 07, 2008, 06:21 PM
Electronic Hobbist
weber_alejandro's Avatar
Mendoza, Argentina
Joined Jul 2007
32 Posts
Quote:
Originally Posted by meteor
Very impressive project, must have been a satisfying challenge to complete.


But, I'm a little confused... Why replicate what is readily available for very little money?

It seems that a garden-variety transmitter project is a lot of effort that could have been used for some other more unique challenge like an autopilot, or data recorder, etc.


Great work, regardless.
Thanks Meteror. I make this project becouse my goal in this hobby is everithing related to electronics. I made my own power panels, battery chargers, battery cycler, diferent instrumments, etc. Spend a lot of hours build them, using it, flying it, there is my satisfaction.

Big part of my learning come from this forum!, and that's why sharing my project with you people; is in fact my honor.

Best regards to all!
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Old May 07, 2008, 11:38 PM
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Manila, Philippines
Joined Jul 2004
1,199 Posts
Alejandro, Yes, I agree with you....your Source files should be readable on any Text Editor such as NOTEPAD or WORDPAD, or even a MS-DOS EDIT.COM.

I can read the TONESX, LCDSER05 files, but can not read the RCENCODER_V1.5 files.....I am using an Microsoft XP windows professional O.S.......Maybe its something to do with your Linus OS.....it might have remove the Line Feed, or Carriage Return,TAB Character.........Please try downloading it again from this Site and view it.

With your Source files, I can just recompile it so that I could use the 16F877 chip.....its much easier to get the 16F877 here in Manila.

I have not done any C language programming, Most of my project is done with Basic Language, I've been using Micro-engineering Basic Compiler...and use ICPROG to program the 16F877.

Yes, Plan to make that Heli-Chair......I've tried flying a Real Helicopter using a Robinson R44, the most difficult it controller the rudder using the Foot, its like learing to Steer the car using your Foot.

here is the Coaxial Robinson R22 with On-board camera
Pilots view:
Robinson R22 Coaxial Helicopter with on-board camera (6 min 19 sec)


Helicopter view:
Robinson R22 on board video (4 min 39 sec)


Here another Pic Base Transmitter encoder project using Basic Language posted by Acetronics (Alain).....its simple 4 channel that use PIC16F877.

http://www.rcgroups.com/forums/showthread.php?t=719250



Thanks

Ellion
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Old May 08, 2008, 07:03 AM
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mike50's Avatar
Rochester, MN
Joined Jul 2003
562 Posts
Quote:
Originally Posted by lazy-b
Alejandro, Yes, I agree with you....your Source files should be readable on any Text Editor such as NOTEPAD or WORDPAD, or even a MS-DOS EDIT.COM.

I can read the TONESX, LCDSER05 files, but can not read the RCENCODER_V1.5 files.....I am using an Microsoft XP windows professional O.S.......Maybe its something to do with your Linus OS.....it might have remove the Line Feed, or Carriage Return,TAB Character.........Please try downloading it again from this Site and view it.


Ellion
The RCENCODER_V1.5 files work fine with Wordpad, just not with Notepad because Notepad only recognizes end-of-line when it sees both a carriage return AND a line feed. Wordpad handles lines that end with just a line feed as well.

So just use Wordpad.

Mike
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Old May 08, 2008, 10:34 PM
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Manila, Philippines
Joined Jul 2004
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Mike, Your Right......Thanks.

I just open it with the WORDPAD, Highlighted all the Text and Open up the NOTEPAD and Paste it, and then Save it again under different file name.

Now, I can open it with a NotePad.......I like NotePad cause some of my old computer using Windows 98.

Ellion
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