Melih Karakelle's Posts (46)

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SimpleOSD OPEN for DIY OSD Project


Hi Everyone,


Maybe you know, we are manufacturing SimpleOSD since tree years and i'm planning to converting it to opensource since one years. 

2 month before Dennis Frie contact with me for an opensource OSD hardware, because he was developing an opensource firmware over Arduino base. I replaced a SimpleOSD board with arduino boot and 16Mhz crystal and sent to test. Results was very impressive and Dennis shared the code with SimpleOSD board support. Now We calling this boards as SimpeOSD OPEN



Today we finished the production of first 20 units of SimpleOSD OPEN boards and they are in stocks now.

Dennis developing MultiCopter and FPV type OSD screens on the firmware and maybe you can help him about APM or other autopilot compatible firmwares? 


Here is the DIY OSD topic on RCG 




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Hi Guys,


I'm working on the MultinoCopter project since 2 months. It is a 50x50mm size board with full compatible arduino pro mini architecture and 9DOF imu. I didnt share it because i have to finish the multicopter code before. Now it is working as a serial IMU for the computer based projects (calculating euler angles) and camera stabilizer. 

Yesterday i tested the camera stabilization code on the 3 axis. The mount coming from a giant rc helicopter and it designed for Canon 7D.


Have a nice weekend


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OpenLRS + wii motion plus

Hi there,
I know openLRS was slowest opensource project ever and i didnt release it since 5 months. But i will do that in 24 hours.
Today i tested the I2C functions for direct stabilization applications. OpenLRS receiver including serial and I2C ports for GPS and Sensors. Add a gyro / acc / magnetometer and you have an multicopter controller (or autopilot). you dont need an external receiver / autopilot or extra cabling between rc equipments and telemetry coming internally too :)

Here is the wii motion plus test video. It's stabilizing Aileron/Elevator and rudder on current setup.

Tomorrow, first products will be in stocks for few lucky Arduino programmer.I will share the schematics and codes too.

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ArduLog Opensource microSD GPS logger

I just finished the coding of our new opensource product ArduLog.


Product name was G-Log before it was being opensource. And i was using it for logging the GPS data of my FPV plane. Now it is opensource, i replaced all AVR-GCC codes with Arduino compatible ones and included Arduino Pro 16Mhz bootloader.

This is the KMZ output from ArduLog


ArduLog is a stamp size circuit which has the capability of doing Serial, I2C and Analog logging. Current firmware logging the GPS positions from it's serial input.

It's including a microSD socket, 2 color led for status and 4 input pin that connected with 6 ports of Atmega328 processor.


Default firmware supporting all GPS models which have standard GPGGA NMEA protocol.

The Baudrate of ArduLog is configurable with putting  the _BAUD.TXT file into the root folder of microSD card.

We tested it with all rates between 4800-115200baud and GPS refresh rates between 1-10Hz

Just create a file that named _BAUD.TXT and type the baudrate into. (like 115200)

ArduLog reads the file on startup and logs the GPGGA sentence of GPS data on every seconds.

Then our free KMZ generator software generates flight path KMZ files for Google Earth.


  • Full Opensource Circuit Architecture and Firmwares
  • Coming with ArduLog GPS logger firmware for Plug and Play FPV usage
  • Supports all GPS modules between 4800-115200 baud
  • Supports all GPS refresh rates between 1-10hz
  • 1Hz record resolution for GPGGA sentence
  • Arduino Pro 16Mhz compatible Bootloader for upgrades and firmware modifications
  • Supports all FAT16 formatted microSD cards up to 2Gb
  • Autoincremental Record File Name
  • Red/Green status LEDs
    Green: card detected
    Red (Continuous): empty slot or wrong card format
    Red (Blinks) : writing



File and Links

Product Page :

Sample KMZ file from ArduLog :

ArduLog Google Code Page for Firmware and updates :

GPStoKML generator Software :

Baudrate Configuration File : _BAUD.TXT

Thanks for reading



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New Circuit for Antenna Tracker

Hi Guys,
I designed a new 6ch servo driver for antenna trackers or robotic controllers.
My plan was sending it first to HappyKillmore for his ground station's compatibility  but he is faster than me and just released a tracking solution :)
Actually it is not a new circuit of mine because i was designed it on December 2009 but it wait on desk for my free time. Now firmware ready for serial usage.
The Circuit including 1 RS232 input and 6 Servo output and size is 20x30mm. 
Command set is very simple for all programmers and languages, no need bit calculation or similar things and possible to use any robotic arm projects. You can type the commands from Hyper Terminal too :)
Baudrate: 9600 baud
Signal Resolution: ~1us 
CommandSet: [Servo Number]+[position_us]+[chr 13]  
[Servo Number] = 1-6 (string)  
[Position_us] = 500-2500 (string)  (the range depends servo)
for example:
"11500"+chr(13)  mean "center position for first servo".
Here is the product page of 6ch serial servo driver
PS: You can order the gimbal (that show on the video) from, it is very tough an very good engineered product.
Thanks for reading
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920nm IR filter for penetrating the mist

Hi Guys,
We are trying to penetrating the mist with the camera that sensitive on IR spectrum.
The video from last days of 2010. The weather was sunny but mist covering the detail of the islands. We tested 720nm, 850nm and 950nm IR photography lenses and 920nm was the best one.  
920nm looking useful but camera sensitivity reducing in this spectrum and need more light.
I will try same setup on misty day on shorter range and will share the results of the experience, maybe it helps someone.
Chers and happy new year
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The OpenLRS Project: PCBs ready for test


Hi Guys,

I received the OpenLRS PCBs and we start to working about firmwares.

This is the Tx module of OpenLRS, It gives 100mw 433mhz RF power and its penetrating behind 5-6 concrete building!, we will test it on flight for range. System can controllable by any PPM signal or over RS232(bidirectional)


This is the Rx of OpenLRS,

It is very small receiver that supporting I2C (for IMUNext) and RS232 Telemetry.  It sends the RSSI level over telemetry and RSSI output (PWM).

And our killer 7W Booster for very long range oneway RC control.



All Atmega328 processors including MegaLoad bootloader for firmware update over rs232. All AVR programmers are welcome.

They will in stocks before 2011.


You can follow the OpenLRS project from here

Cheers and Mary Christmas


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New OpenFGS Ground Station



Hi Guys

This is my new ground station (and my smiley face)

I'm developing this software since 3 days (yes i know i'm too fast, because this is my job since 20 years)



It's working with my new SimpleOSD telemetry protocol over FrSKY's bidirectional RC modules. Protocol is very simple and it is sending all gps+battery values in 21bytes pack (1bytes deviceID+18bytes data+ 2bytes end of line data).


  • It is OpenSource (under LGPL license)
  • Live Video
  • Live Google Maps position
  • Video Capturing with all compression codecs.
  • Data logging and others.

And i will add OpenLRS telemetry support with IMU and other sensors on Alpha version of firmware. Then i'm planning to design a PC based Autopilot system into the ground station. Because PC based programming easier for most of pc programmers.


You can follow my all FrSKY telemetry projects from this link


And this is the google code page of OpenFGS project.

Please contact with me for being  the project member, all developers are welcome.


Thanks for reading





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7W boosters for OpenLRS Project

Hi Guys

Good news from OpenLRS (Opensource Long Range System) project!

Today i received 7 watt RF booster chips and at last i'm ready to finishing the PCB designs. This weekend i will finish the booster design and PCBs will be ready in 3 weeks.

Here is the latest PCB designs of Tx, Rx and IMU modules of OpenLRS

Tx and Rx modules size smaller than most of RC modules. Rx module including I2C (or 3 adc) conector pads on back side. I'm planning to connect my new 6DOF IMUnext v3 board there. Rx can stabilize the plane (or quadro) without any external parts and it sends the parameters to the ground over telemetry system. And Rx's rs232 port already available for digital telemetry or direct GPS connection.

Some advantages of OpenFARC:

  • Direct ground computer based remote control and telemetry (Autopilot by computer?)
  • Rx based Autopilot/stabilization/return to home.
  • No Frequency hoping. I'm planning to using static 2 frequency switching for safety. You can use 2 or more modules for receiving the telemetry signals or transmitting the controls with static frequency, because you know your frequencies. Or hopping already possible.
  • If you want to use it for really long range, you can add 7W booster on Tx module (only one way control without telemetry)
  • Direct analog RSSI output on Rx
  • RS232 telemetry and commandset (like "S2512" mean turn the 2th servo to center position,etc)

I'm developing OpenLRS project with AVR-GCC on Atmega328 chipset. All ATMEL developers are welcome ;)

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Serving the Electronics


We( were thinking about turning our projects to opensource for a long time. But we were not sure about the way and procedures.

Then, this weekend I read and inspired Chris Anderson's great 10 Rules of Maker Businesses article. His all of the rules %100 right about our business. We find same rules after 2 years work except Opensource side of this job.

After this great article, we (me and Bora) decided to opensource development of our all projects. This is very hard for us because we have 20+ different products. Writing the manuals and explaining the codes will take long time but we will.

At first, we will share the design and codes of our RXBee (Xbee based radio tx/rx for robotic servo controls). Then the OpenFARC (Opensoruce far aerial control) project will follow them. I hope you will like it.

Thanks Chris :)

If you want to see how we cook the delicious electronics, please visit our blog. We will post everything there on every day.

Thanks for reading


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New Opensource LRS Coming

Hi Guys,

I just finished the test of our new opensource long range system modules.
This modules 3th generation and i guess i should design 4th generation before publishing them.


I'm using RFM22B radio modules and ATMEGA328P chips on Rx and Tx.
Rx modules including 8 channel servo ports and RS232 for telemetry uplink

Tx modules including PPM-Input for analog servo control and RS232 for Computer based controls and Telemetry downlink.

System range will be around 4-5km.

Firmware Upgradeable over RS232.

Ground tests was unbelievable, it's working around 500 meters into the city (after 20+ concrete building)

I will share the flight test results, sources and schematics soon.

If you have any idea about design and inputs, please share with me before 4th generation's production..

Thanks for reading


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36x Zoom Camera Daylight and IR 850nm Test

Hi Guys

We just tested a new camera with 37x Zoom.
This camera including optical isolated RC servo line controller for zoom control via RC

Sun was down since 30 minutes and 850nm spectrum already giving high contrast details in this conditions.

IR 850nm band looking good option to separate the object from the background on the nature (threes and sea)
Maybe I shell try it on a plane.


Mounting Holes on metal chassis


Button Interface and Optical isolated control inputs (Zoom/Focus/RS485)



Weight: 190gr
Dimentions: 105x50x55mm
Optical Zoom Factor: 36x
Sensor: 1/4" sony super HAD CCD
Focus/Iris: Built in Auto Focus/Auto Iris
Digital Control Protocol: RS485
RC servo channel control: Zoom control with auto focus

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Hi Guys,

I designed this protocol since few months ago but it lost in hole of internet.
I hope it helps someone.

Everyone using video transmitters on UAV/FPV planes and audio channels empty or only transmitting propeller sound, this is why i designed this telemetry protocol on audio ;)

Advantages of Audio Telemetry Protocol (ATP)

  • You don't need any extra hardware except your Autopilot/OSD's processor for transmitting datas
  • You can receive all data without any hardware with your PC/laptop
  • Audio channel less noisy than video
  • %90 of video Tx/RX modules supports ATP's 2000-1300hz audible waves without any problem

How ATP Works?

ATP uses AFSK method to sending telemetry data over VideoTX’s audio
channel. The carrier is 2100Hz and a byte starts with one 1300hz wave(start bit), ATP sends
data bits after the start bit. and it sends minimum 10 carrier wave(zero) before a new start bit.
You can read my detailed information from this link (sorry for my English):

Code Example for Atmel Users

Calibrating a PWM generator for 2100Hz carrier wave (for Atmega328)
TCCR1B   =   0x00;   //stop timerTCNT1H   =   0;TCNT1L   =   0;
ICR1 = ((Xtalfrequency/8) / 2100); //2100hz carrier generator value 878 for 14.7Mhz
OCR1B = ((Xtalfrequency/8) / 2100)/2; // ICR1 / 2 for %50 PWM waves
TCCR1A = 0x22;
TCCR1B = 0x1A; //start timer
This code generates static 2100hz square waves, put a 100nf capacitor on outside of processor and connect it on Audio in of TX, now you have a sinus on RX side ;)

You can send the bytes any time in your main code flow because AFSK protocol following waves not time sensitive protocol.
modem[] is an byte array that filled with data to send.
modem_byte is an integer for selecting byte of modem[] array
modem_bit is an char for counting sinus waves of AFSK

This code sends start bit at start and 8 bit of byte,
you should wait for 5ms for next byte for balancing sinus waves on audio stream, then you can send another byte also.
modem_bit = 0;while (modem_bit<18) //wait for all bit waves        {

if ((modem_bit%2==0) && ((PINB & (1 << 2))) ) // wait for 1 on PWM output.
if (modem_bit==0) // start bit
TCNT1H = 1; // this values creates small delay for increasing the wave width
TCNT1L = 180; // and AFSK decoder can detect this big waves to 1, other small(2100hz) waves 0

if (modem_bit>1)
if (modem[modem_byte] & (1<<((modem_bit-2)/2))) // if bit of bte is 1, change the wave width for 1 on AFSK
TCNT1H = 1; // this values creates small delay for increasing the wave width
TCNT1L = 180; // and AFSK decoder can detect this big waves to 1, other small(2100hz) waves 0


if ((modem_bit%2==1) && (!(PINB & (1 << 2)))) // wait for 0 on PWM output

ATP Modem Software

I wrote a modem software for reading AFSK waves without any hardware (maybe a serial 100k resistor on microphone in)
File name is: SOSD_Modem.exe


This is only software modem on the planet (or i didn't see another) :)
It is decoding AFSK codes from microphone input like an oscilloscope and giving output values from TCP for 3th party softwares. You can design your loggers, goggle earth interfaces or more with this plug.

It is using 20byte data pack for transmitting and software can separate them
First 16 byte is data bytes last 3 byte is line end and CRC
Pack of Bytes
[0-3] Latitude (4 byte = 32 bit long integer of coordinates)
[4-7] Longitude (4 byte = 32 bit long integer of coordinates)
[8-9] Altitude (2 byte = 16 bit long integer of altitude)
[10] Heading Angle (multiply it with 1.4 for finding angle value)
[11] Battery 1 voltage (divide 10 for value, 111 mean 11.1Volt)
[12] Battery 1 voltage (divide 10 for value, 74 mean 7.4Volt)
[13] Current Sensor 1 (multiply with 0.4 for value, 101 mean 40.4Ah
[14] Current Sensor 2 (multiply with 0.4 for value, 101 mean 40.4Ah
[15] RSSI (It is percentage of maximum value, 35 mean %35)
[16] Speed (km/h)
[17] Line End 1 (value 10)
[18] Line End 2 (value 13)
[19] CRC ( 8 bit totals of first 19 btye)

If you uses my original data pack Software Modem giving this type output from port 1976 (my birth year)
$TELE,lat,lon,alti,heading,voltag1,voltage2,curren t1,current2,rssi, speed, #13 #10

Or you can use your own data pack and you can decode them yourself from modem's RAW data output.
$RAWS,byte0,byte1,byte2,byte3,byte4.........,byte16, #13 #10
then you can decode your data bytes(first 16 byte)

This software only part of ATP i didn't share the codes because i want to share the protocol with all autopilot/OSD producers and i want to use their 3th party tools too.If I share the code, they can change only AFSK frequency and visuals for non compatible products.

New Features

I added direct KML file based live view for Google Earth on the new version of modem software.
You can click on plane_tracker.kml file and Google Earth connects your Modem Software to tracking the plane :)
It is already primitive because we have some connection problem on Google Earth since few months :(

Story Of ATP

If you want to read all discussions follow this link:

Thanks for reading

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New GPS to microSD Logger design requests

Hi Guys,

I was design a SD card logger circuit since months but i didn't share it because Atmega328s have stock problem since 10 months and the smaller controller's capacity not enough for this device.
Anyway We just received 250 units Atmega328 and it will finish in few days.
I need your guidance for capabilities of this device. Please feel free about any comments or requests

This is the SD logger circuit.


How it Works

We will connect it on any GPS wiring(parallel) and it will reads all transmission between GPS to Autopilot/OSD and records on SD card. And we can read the flight path with a PC after flight. I guess it will good option for T3 competitions or other logging requirements ;)

Information About Hardware

  • Supporting 0 to 115.200 baud RS232 transmissions,
  • I2C support is possible
  • It's including 2 x 10bit ADC pin-outs for analog logging features (maybe for different projects)
  • FAT32 file support for SD and SDHC microSD/Trancent cards
  • Firmware Upgradeable over RS232 with Megaload boot loading system
  • 4-12V supply voltage
Possible Features of Device
  • Direct KMZ file generating from GPS data
  • Full stream GPS data logging (I guess useless satellite azimuth values must be spitted)
  • Automatic file name generating from Time and Date (it creates different files for every hours)
  • Max. 10Hz GPS support (My personal suggestion: 1 Hz is enough for clear path)
  • Configurable over a config.txt file for all features.
  • And Please share your suggestions about these and another possible features :)
Thanks for reading

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First Tests of IMUNEXT v2 controller

Hi Guys,

I was design IMUNEXT v2 board on this March but i didn't find time for testing and working with it.
Now i have a time for this because my Quadrocopter, Camera mount and Plane waiting for stabilisation ;)

IMUNEXT v2 including 8 channel servo IN/OUT , Serial port for XBee modules or GPS, Serial PPM input for external controls.

I'm planning to share opensource codes and circuit schematic for designers. You can load your own code into ATMEGA328 core.

I will share Quadro and Plane tests when they are available.

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UAV like video with Depron Plane

Hi Guys,

We shot a video on this morning. The platform was a depron PolyClub, weather was perfect for this light airplane.
We have 2 camera on the plane, one of camera on tail, other one on right side of plane(45 degree angled to the ground) Side camera perspective is unbelivable and i'm strongly suggesting to watch all video :)

Have a nice weekend :)

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Hi Guys,

Maybe you know, i'm designing FPV electronics but this product not for FPV :)
We are sharing same flight field with gliders,glow and electric planes and most important problems was switches for everyone.
This is why we designed this small circuits

Standard slider type switches are the most important crash reason on glow planes/gliders and they can affect from vibration, dust, oil and moisture.
Ultra Reliable Switch works when only slider switch mechanical off, and you are forcing to close it when switch on. This electronic design uses high power MOSFET for opening the switch and current limit is extremely higher than all mechanical switches.
We are using 20Ah MOSFETs for this small switches and they can handle 100Ah peak currents on hard conditions.
You can use it with your Gliders, Glow planes or Small EP planes.

  • Low Quiescent Current (50uA on 5Volt)
  • Very Low Internal Resistance (0.006 Ohm on 5V)
  • Wide Operation Voltage (2-30Volt)
  • Very High Current Resistance (20A Continuous, 100A Pulsed)
  • Onboard LED indicator
  • Large Soldering Pads
  • Receiver battery switching for Glow and Gliders
  • Ignition system switch for Fuel Engines
  • LiPO switch for small EP planes (20A Max)
  • Safe Switch for other hobby electronics


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TIR - Tactical Inspection Robot

Hi Guys,

I know it is a little bit off-topic :)
I was a Recon Scout Fan since years and this morning we found 2 hours time for relaxation on the Flytron Workshop. Then we have a tactical inspection robot :D

It is a fun project but maybe we should work for a real one with IR spots and microcontroller :)


  • Flytron FC-422 submicro camera
  • Flytron FTX-50 50mW micro video transmitter
  • 2 geared motor
  • 2 mini motor controller (servo electronics)
  • 1 Bluearrow 35mhz Receiver
  • 2 mini 138mAh LiPo Battery
  • 2 old park flyer plane tires.
  • Pine wood stick for body construction
  • tire-up and some adhesives



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