roxblog

THE RISE OF THE DRONE ERA

2019-04-28T12:59:00.002-07:00

UPDATE 1/1/2017 Due to new legislation about drones I cannot fly my drones any more because they need an airworthiness certificate from Hellenic Civil Aviation Authority. Never mind, the costly Li-Pos are already exhausted and I thing it is about time to move my autonomous vehicle interests to other more legal regions :) .So far so good then, I learned a lot about autonomous vehicles and most certain I HAD A BIG FUN FLYING THEM (and a huge aerial photo collection).

Ok let's admit it. Can somebody who likes microprocessors, GPS's and high tec electronics stay away from drones? Nay !!!! So I entered this uncharted region plenty of fear due to the fact that I had once lost a model airplane due to my ignorance of how to fly model airplanes. However I have no fear at all to make a car - ship - airplane - drone -submarine - whatever. So I acquired some aluminum plates, bars, tubes and 3mm inox allen screws and bolts, purchased from E-bay motors , propellers, batteries , autopilots ,GPS , telemetry modules and here it is.... my first drone back in 2013 IN FLIGHT !!!

First quad in flight - RIP

RIP ??? How's that ? Well , I went totally unprepared, without on board pilot camera, no video link, just a simple short range bluetooth telemetry, a 1HZ GPS module (the late EM406) which took for ever to lock , no failsafe programmed on autopilot, on a windy day to a mission which seamed very easy, very close to my house. Failsafe was a nuisance to program and once the quad returned to launch (RTL) on his own and crashed before I understand what happened. I flew it without gps lock and when it got over 30m it drifted away due to strong winds. I tried to bring it back but since I had no colored stripes (or colored propellers) on any of the arms to know where it was heading , I drove it further away and it just disappeared from view towards a hilly forested area. Needless to say that my flying skills were (and still are) NULL.

The broken propeller issue and Murphy’s Law

"Even if you fly in a totally bushed area your drone is going to crash on that single rock between the bushes." The frame below shows the propeller blade separating and causing a drone crash. At first I thought that responsible for the crash was some kind of RF interference. The on board video camera caught the culprit : We had an in-flight propeller blade separation.

propeller blade separating

...and that single rock

Quad MK II

After considering more seriously about flying drones I assembled the MKII. It still flies today (2016) despite a few crashes that costed me no more than a few propellers and some twisted aluminum arms and plates. Here it is:

Quad MK II

Lessons learnt

Don' t use cheap 9.6 inch propellers on a 1.5kg drone - they use to flip on air (happened to me twice).
Cheap batteries have unexpected behavior .
Use video link and a camera for the pilot
Wind velocity rises dramatically 30m or higher or when clear of trees or houses.
Schedule your mission very carefully
Be sure that telemetry and osd video are working
Do a range test
Check for RF interference
Program failsafes
Wait for the gps to lock.
Stay away from people -cars -airplanes and generally urban areas - 1.5 kilos is not a negligible weight when falling from 70m
Do preflight tests based on a thoughtful prepared list
Connect the battery low warning buzzer
Put a lost model module buzzer on an unused channel
Write you phone number on the drone.
Use different color for the drones back arms.
If you 're not a competent pilot, then let the electronics fly it for you - believe me they can do it both economically and safer too.

I decided to fix some of the problems discovered during the first and second drone development.

The drone should have ample space for the onboard electronics and they must be accessible without major strip down.
Video camera - the excellent Mobius actioncam - should be on a proper gimbal offering unobstructed front view and placed well away from the propellers.
The drone must be foldable and could be easily carried in a plastic tube of 15cm diameter.
Battery must not hit the ground, but it must be housed and protected inside a frame, and able to be moved to adjust the CG of the air-frame. (this is accomplished by using velcro straps)

The new drone named MARK V (MK V) was designed back in 2015 from scratch using a CAD software .
3mm and 0.8 mm aluminum was used for the baseplates and 1x1 1.2mm aluminum "Pi" frame for the arms.
Notice the orange colored tape on the back legs .....

CAD of quad MK V

Quad MK V

Coming soon (?) ...

WTF is this ?
Be patient guys, if I 'm too much occupied with this blog I will never finish my projects.....Sorry

AUTOPILOT MEGA (APM) - Now, we 're getting serious

2016-12-10T00:22:00.001-08:00

Well beyond ardupilot I (best known as ardupilot legacy) , the excellent APM 2.5 (or 2.x) hardware and corresponding firmware gives the opportunity to fully explore the potential of modern mems devices and other electronic modules. In particular , using modern ultra fast and cheap GPS modules from China such as Ublox NEO 8M we can develop UAV's with astonishing position hold and track follow accuracy.

My new (gen II) auto piloted car is based on a simple wireless remote controlled jeep given as a NiCd battery discharging device with a SKILL portable drill. I changed the motor driver with a quick-and-dirty perf board with an ATtiny2313 and a L293D to control steering and traction motors.

ATtiny 2313 and L293D dual channel PWM motor driver

Then I (over) loaded the little toy with an APM 2.6 autopilot, a 5V power module,a Ublox GPS, 915MHZ telemetry module, 2.4Ghz R/C receiver, servo camera (or antenna, machine gun, whatever) gimbal, 5.8 GHz video transmitter and a 3c 2200mAh LiPo battery. It finally looks like this :

APM inside

Without camera or 5.8 GHZ video transmitter

This particular rover is a fine platform for developing and testing autopilot modes, ground control stations (GCS), PID controller behavior, GPS accuracy, R/C remote - telemetry - video range , power consumption and electronic interference between modules. Its maximum speed is 0.4m/sec but with an 2200mAh LiPo battery it can travel for hours with everything on, and you can’t lose or crash it. You can hardly wear its "tires" too.

Let's see it in action at night with an automatic mission with 4 waypoints. Using the Ublox 8M GPS (16 satellites HDOP 1.35m) we get the following astonishing results regarding the track repetition accuracy of a such an economic combination of hardware and firmware !!! (even multipath issues are not affecting GPS performance -what else can someone ask ?)

Night testing of GPS - autopilot accurancy

On Michael Oborne's excellent Mission Planner GCS we can clearly see the telemetry data and 5+ track repetition accuracy.

Ublox 8M GPS impecable performance

Ublox 6M GPS has a decent performance as well

This little thingy has travelled literally lots of kilometers without any issues. Just charge the battery and go on. You can 't imagine the joy you get when seeing this little fellow driving on after one and a half hour, hitting one waypoint after the other with more than 60% of battery remaining !!!.

MAXIMUM RANGE OF ULTRASONIC MODULE

2013-03-21T02:10:00.000-07:00

A trivial application of ultra cheap Chinese ultra-sonic modules like the US-020, is to use it as range finders. The question is what is the maximum distance we can measure. These modules have an on board microprocessor and so we don't have any access on front end receiving amplifiers or transducer driver stages. The signals we get are pre-processed. A search through the available cryptic manuals on the net depicts a polar diagram that shows max distance about 10' (~300cm) which is far less than the 400-500cm advertised on ebay.

We wanted our setup to be portable in order to have some outdoors measurements. So we connected our arduino mini to a linvor slave bluetooth module and used our mobile android phone as a terminal using an excellent free android application named Bluetooth SPP by Jerry Lee. Bluetooth SPP realises the SPP bluetooth service on an android device and is rock solid, much more robust than standard microsoft SPP service on ms Win XP BT stack. Plus, it includes a file logger !! At first we measured a distance of approx 5 metes and we certified it with a laser rangefinder. Accuracy is pretty good (within 1 cm ) for such a low priced device and consistency is impeccable as you can see in the following video.

Searching for the maximum distance in a noisy outdoors environment was quite difficult. We used an office chair to be able to rotate the measurement setup on the horizontal plane. At last we could get 1009 cm as the maximum reading in our terminal while 1135 cm seems to be our maximum software limt. Accuracy was in the range of 5cm and consistency was not bad at all using a simple software filter that rejected erratic measurements.

CENTRALIZED SPLIT UNIT AIRCONDITIONING CONTROL

2013-01-03T11:59:00.000-08:00

Maximum HVAC efficiency is obtained with the use of inverter airconditioning units that have a CEP 3.5 or more.
The idea is to control some (3 or more) sets of split type airconditioner units with a central (master) unit. This master unit runs a time schedule by reading the onboard RTC, logs data and slave responces to a micro SD card, communicates with the slave units via RF24L01+ modules at 2.4GHZ and even takes care of local room temperature by reading a precision centigrade temperature sensor LM35Z and controlling the local airconditioner unit with an IR led that emulates the original (Hitachi's) infrared remote control. And last , but not least, an input from a power meter (like an Electric Owl CM160 ) monitors electric power consumed by all air conditioner units to prevent power overload.
Slave units comunicate with master via RF24L01+ modules, read temperature with a LM35's as well , and send infrared commands to the remote airconditioner units. In case of RF link failure they can even take over local control.
All units are based on Arduinos's MCU's. Behind the idea of centralised HVAC control is, of course the optimisation of mains power consumption. Below is a photo of a master unit prototype. On the prototype shield on top of an Arduino duemillenove, you can see the RF24L01+ module, the RTC module (a DS1307) with the backup battery, the infrared led and 2N2222 driver. The temperature sensor LM35Z is behind the RTC module adjacent to the analog pins of the shield. Sd card is an optional add-on . On the paper are my so-far failed attempts to decode the manchester-encoded pulses of the electric Owl's CM-160 receiver output. On the oscilloscope you can see the infrared pulses that control the shutter of a Pentax X-5 camera which plays the role of the receiving airconditioner unit just to make sure that no interrupt handling inside RF24,RTC,SD,SPI or WIRE libraries interferes with the time sensitive infrared carrier signal of 38.4KHZ Two buttons are also provided to send commands like "emergency Power OFF all units" or "set all units to SLEEP 1H mode".

Master unit prototype

Code on the master unit takes approximately 26K of flash memory and on the slave a mere 14K.(Atmega328). We can also provide all units with PIR detectors to sense human presence and to inform master to take care accordingly. Every unit can also be connected via USB to a pc for debugging purposes.

CAMERA SERVO ADD-ON

2012-10-06T02:39:00.000-07:00

Here is a servo adapter for non-infrared remote controlled cameras. Upper servo controls shutter and lower zoom functions. Servo position can be adjusted to fit multiple camera makes. The video shows adapter controlled by the arduino universal remote camera controller which controls the camera array of my previous post.
.

This adapter can be controller by a pc via an rf (xbee) link or arduino's serial usb port , the mini remote control shown here, the hacked helicopter remote control of the previous post, any PWM R/C remote or by using time lapse and PIR / infrared barrier ports /buttons on board arduino pcb

REMOTE CONTROLLED CAMERA ARRAY

2012-09-18T01:21:00.001-07:00

I really like remote controlled cameras. Unfortunatelly, affordable ones are very rare these days (like Pentax Optio S1) . An infrared remote control was considered standard accessory during the good old days of mini-dv and other tape camcorders but now one has to try hard to find the little red-purple piece of plastic at the front face of contemporary video equipment.
So,I decided to make an arduino infrared remote controlled camera array . An arduino prototype board with an infrared led and two servos controls at least four different pieces of video equipment and has a few options useful for nature and wild life photography as well. A motorized camera rig is on the way.

Oblique view of the camera array

Rear view of the camera array

Camera array in action

Arduino sends infrared remote codes to the cameras in order to control functions like shutter press/release, zoom in /out, snapshot recording and video recording toggle. Arduino infrared is controlled remotely by either by a PWM R/C remote control , a serial digital link (or Xbee) , a 433MHZ 4-Channel button remote control or locally using butons on the arduino board itself. Even two servos can be connected on the board to control shutter and zoom in manual-only cameras. A relay output and an user configurable input can be connected to a PIR detector or an infrared barrier.

A "hacked" 433MHZ radio link -we just get TTL Rx/Tx signals and 5V to feed Arduino

Arduino infrared prototype feeded by a 7.4V LiPo (5400mah!!) , a 3A/ 5V swiching regulator, and a hacked 433Mhz serial link . Bottom center is the Infrared led and one of the two optional servos for shutter and zoom functions.

The not-so-innocent cheap helicopter model remote control and hacked 433Mhz serial receiver. Everything inside original remote was discarded and a 433Mhz serial link (the same as the receiver) was added together with an arduino mini at 16 Mhz, another two axis left joystick and two extra buttons below it. Power comes from 4 NimH batteries and a 5V/3A switching regulator, Line-of-view range is about 300 meters.

Arduino infrared prototype is controlled by an -also hacked - 4-channel 433 Mhz garage door receiver. The minimalistic remote shown on the right has a line-of-view range of 300 meters ! It can control shutter , Video recording and Zoom functions of every camera in the array.

2 channels of a common PWM R/C receiver are connected to the arduino prototype. We can control shutter , Video recording and Zoom functions of every camera in the array also, using flap (CH6) switch for shutter and Video record toggle, and throttle (or elevator) joystick (CH3/CH1) for Zooming functions.

Another useful option is the built-in intervalometer which takes time-lapse videos like this one :

You can see a FHD of the above video if you click on the following link :

http://www.youtube.com/watch?v=aEV3MGRP8cs&feature=plcp

or this one :

MEADE ETX-70AT TELESCOPE REMOTE PC AND ARDUINO CONTROL

2011-09-26T20:44:00.001-07:00

These fine nights of September when Orion rises early the morning above the horizon, and Jupiter dominates the sky, its a pleasure to use the small ETX-70 telescope guided by its Autostar 494 controller. That telescope costed a mere 200 Euros at Lidl and in my opinion it isn't just a fine little telescope for the beginer, but it's also perfect for land surveing. When Lidl sold its Bresser microscope (another 60 Euros welll spend), it supplied it with a USB camera that fits not only to the microscope , but via an (supplied) adapter to the 1.25' eyepiece holder of the ETX-70. Even though the USB video adapter has a resolution of just 640 x 480 pixel , it is very good for land surveying as shown on the following video. At this case the distance to the subject (the Mi-8 Helicopter) was about 2.5 kilometers, temperature was about 27 deg. C, a sea area existed between the scope and the target and atmospheric conditions far from perfect. Barlows 3x lens was also used that deteriorated the resolution but I wanted to push it to its limits.

From the point of view of an electronics engineer the most interesting feature of the ETX-90 , is the precise guiding mechanism which can be controled by the computer's serial port. All you need is the optional 506 cable set from Meade which is actually an RS232 to I2C adapter that connects to the AUX port of the microscope. A lot of info is written about Meade's serial protocol but the best way to learn about it (exactly as I did) is to tap the serial cable and spy on the data when controlling the telescope with a proper software such as Drsoft 's Meade control panel , Carte des Ciels or Stellarium. A much more elegant solution to taping the cable is to duplicate the controling serial port using a serial to ip server, and open a teminal (like TeraTerm) at 9600N81 to view and log the traffic.After all my finds were :

#:Mn# Slew north (up)
#:Ms# Slew south (down)
#:Me# Slew east (left)
#:Mw# Slew west (right)

#:Mw##:Mn# Slew right up    (NW)
#:Mw##:Ms# Slew right down (SW)
#:Me##:Mn#   Slew left up    (NE)
#:Me##:Ms#   Slew left down   (SE)

#:Qn##:Qs##:Qe##:Qw# Stop movement after above commands
#:Q# Stop movement for all motors

#:Sw2#   Slew speed slow
#:Sw3#   Slew speed medium
#:Sw4#   Slew speed fast

FOCUS CONTROL - there isn't any focuser on the scope - we will talk about it later.
#:F+#   Focus +
#:F-#   Focus -
#:FQ#   Focus Stop
#:FF#   Fast Focus
#:FS#   Slow Focus

After reading the excellent info on http://www.weasner.com   I learn that : " when typing a single control-F on the terminal the Autostar should echo an "A" or "P" depending upon whether it's
set up as Alt/Az or Polar mount status and when typing #:GVF# it should respond with its identification string, including the word Autostar and a time and date (when that firmware version
was built at Meade) ".
Indeed :
Ctrl -F    ---> A
#:GVF#   ---> #Autostar|A|12Ea #

RECHARGEABLE BATTERY QUALITY MONITOR

2011-09-10T22:25:00.000-07:00

Using micro-controllers one can easily (!!!) make an intelligent rechargeable battery monitor in order to check if his NiMh or Nicads are in good condition. Let's take my favorite Arduino for example. It has 6 analog ports, so we can take a six battery holder, cut all inter-cell connections (they are connected in series), put a resistor in series with each cell (it we are keeping it simple - a current source would be much better) and measure and log the voltage as it drops through the resistor. We could also program some kind of Processing script to display the results graphically on the computer.
Well, I used a different - and faster approach. I used my intelligent 10-cell charger and my Sony TRV-22 DVR in photo mode and its simple intervalometer. TRV-22 can take photographs every 1, 5 or 10 minutes in memory stick (120 photos 640x480 resolution on 8MB memory stick) I fully charged the batteries and then discharged them , photographing the charger's leds every 10 minutes. When a cell is being discharged a red led flashes slowly and when discharging is over it lights steadily until full charge when it finally becomes green. The fist discharged battery is the weakest and the last one has the maximum amount of energy. In the following time- lapse video you can see that batteries 8 and 9 are the first to begin charging (that means that are the first to discharge - the ones with the less energy) because their leds lite steadily first of all the others. Battery number 3 is the best because its charging begun 2h 45' after no's 8 and 9 (by examining the EXIF metadata in every pictures file).
Night vision is enabled on TRV-22 because most of the process took place at night. Here is a video of the discharging sequence :

The above procedure can also be accomplished with a web cam and a capture program with intervalometer function. There are a few free ones on the web. Timing error if 10 minute interval is used is +/- 10min. Following time lapse video shows charging sequence :

DRAGON BOAT

2011-09-05T14:36:00.000-07:00

Dragon boat is a wooden speed boat model made in Japan at late 50's. Japan's economy was trying to recover from WWII and toy companies (like Ito) used Japanese households to assemble their products like this one. My grandfather who was a sailor gave it as a present to his son (my late uncle) and my first thought was to use it to tow the depth sounder platform in order to accomplish some lake topography and bathymetry missions. Later I discovered (the hard way ) that these thoughts were disastrous for the boat model and potentially dangerous for me.
The Dragon that gave the name to this model was once painted on both sides of the boat. Unfortunately it was so worn-out that I had to wipe it out completely.
Anyway, I made an ESC with a picaxe and two mosfets and I used a standard servo for steering. The 35MHZ receiver antenna is visible on the following images

Here is a rather shaky video. I'm sorry for this but it 's quite difficult to take video and pilot the model simultaneously.

INFRARED REMOTE CONTROL CODE HACKING FOR AUDIO - VIDEO DEVICES

2011-09-05T13:09:00.001-07:00

Remote controlling audio-video devices like cameras, DVR's , VCR's is one of my favorites.

Imagine remote controlled pan - tilt cameras for wildlife photography, target acquisition etc !!

SONY DVR TRV22E-TRV11E infrared remote control hack

At first a pulse of 2.4ms (of 38khz) must be send followed by a 600us pause
"1" (38KHZ ) duration is 1200us, "0" (38KHZ) is 600us and inter-digit (pause) duration is 600us.
After last bit we have a pause of 19.5ms. Each pulse train must be send 3 times.

{1,0,0,1,1,0,0,1,0,0,1,1,1,0,1}   Start-Stop Recording
{1,0,1,0,1,0,0,1,0,0,1,1,1,0,1}   Snap Shot
{0,1,0,1,1,0,0,1,0,0,1,1,0,1,1}   Zoom In
{1,1,0,1,1,0,0,1,0,0,1,1,0,1,1}   Zoom Out

JVC GRD-240E DV camera infrared remote control hack

At first a pulse train of 8,8ms (of 38khz) must be send followed by a 4ms pause
"1" (pause ) duration is 1500us, "0" (pause) is 600us and signal (38KHZ) duration is 600us.
After last bit we have a pause of 17.5ms. Each pulse train must be send once.

{1,1,0,0,1,0,1,1,1,0,0,1,1,0,1,0}   Start-Stop Recording
{1,1,0,0,1,0,1,1,1,1,1,0,0,1,1,0}   Power Toggle
{1,1,0,0,1,0,1,1,1,0,1,1,1,0,1,0}   Snap Shot
{1,1,0,0,1,0,1,1,0,1,0,0,1,0,1,0}   Zoom In
{1,1,0,0,1,0,1,1,1,0,0,0,1,0,1,0}   Zoom Out

Fujifilm Finepix S2000hd infrared remote control hack

At first a pulse of 9,2ms (of 38khz) must be send followed by a 4.48ms pause
"1" (pause ) duration is 1620us, "0" (pause) is 600us and signal (38KHZ) duration is 580us.
After last bit we have a pause of 40.6ms. Each pulse train must be send once.

{1,1,0,1,0,0,1,1,0,0,0,0,1,1,0,0,0,1,0,0,0,0,0,1,1,0,1,1,1,1,1,0} PHOTOS |>
{1,1,0,1,0,0,1,1,0,0,0,0,1,1,0,0,1,1,1,0,0,0,0,1,0,0,0,1,1,1,1,0} MENU / OK
{1,1,0,1,0,0,1,1,0,0,0,0,1,1,0,0,1,0,0,1,0,0,0,1,0,1,1,0,1,1,1,0} FUNCTION
{1,1,0,1,0,0,1,1,0,0,0,0,1,1,0,0,0,0,0,1,0,0,0,1,1,1,1,0,1,1,1,0} DISP / BACK
{1,1,0,1,0,0,1,1,0,0,0,0,1,1,0,0,1,0,1,0,0,0,0,1,0,1,0,1,1,1,1,0} Right Arrow
{1,1,0,1,0,0,1,1,0,0,0,0,1,1,0,0,0,1,1,0,0,0,0,1,1,0,0,1,1,1,1,0} Left Arrow
{1,1,0,1,0,0,1,1,0,0,0,0,1,1,0,0,1,1,0,0,0,0,0,1,0,0,1,1,1,1,1,0} Up Arrow
{1,1,0,1,0,0,1,1,0,0,0,0,1,1,0,0,0,0,1,0,0,0,0,1,1,1,0,1,1,1,1,0} Down Arrow
{1,1,0,1,0,0,1,1,0,0,0,0,1,1,0,0,1,1,0,1,0,0,0,1,0,0,1,0,1,1,1,0} hex 2 Zoom In
{1,1,0,1,0,0,1,1,0,0,0,0,1,1,0,0,0,1,0,1,0,0,0,1,1,0,1,0,1,1,1,0} hex b Zoom Out

Important !! Last two commands are not implemented at the official Fujifilm remote control.

INFRARED REMOTE CONTROL CODE HACKING FOR HVAC DEVICES

2011-09-05T13:04:00.000-07:00

In a modern house , most electronic devices are controlled by an infrared remote. Hacking the infrared codes gives you endless possibilities: Using a micro controller you can built an universal HVAC controller which can map the desired indoor temperatures and control all devices like air conditioning units, ceiling fans , heaters etc. You can use input from:

outdoor/indoor humidity temperature and solar radiation sensors
input and return water temperatures from heater
solar collector and/or electric boiler temperatures
time of day - season rtc
solar radiation sensors
movement sensors (to control temp of an occupied room)
internet weather forecast data
rain sensors

to control

oil boiler set point
air conditioning unit temperature and/or functions (eg dehydrating)
ceiling fan speed to equalize temperature in a room
fan coil fan speed control

To be more specific you can control oil boiler set point by using a common servomotor connected mechanically to the water temperature knob, infrared diodes to transmit commands to airconditioning units and ceiling fans. I personally use three one-wire (or LM35DZ) sensors (one at the floor level, one at 1m height (bed level) and one at 2.8m (ceiling level) to control ceiling fan speed in conjunction with all other HVAC devices to maintain a steady comfort temperature and to not waste energy by over heating ceiling in winter or over freezing floor in summer. Using movement sensors the system knows when a person is in the room and acts accordingly - even at night when the person is sleeping.

Below are some hacked infrared codes from my HVAC devices:

HITACHI Inverter Air conditioning

At first a pulse of 9,2ms (of 38khz) must be send followed by a 4.48ms pause
"1" (pause ) duration is 1620us, "0" (pause) is 600us and signal (38KHZ) duration is 580us.
After last bit we have a pause of 40.6ms. Each pulsetrain must be send once.
All pulses must be send. I have to separate them in command and common parts in order to use a micro controller for temperature control.

Power on (All Auto -mode auto, fan speed auto, set temp auto)
{1,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,1,1,1,1,1,1,0,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,1,1,0,0,1,1,1,1,0,0,1,1,0,0}
{0,1,0,0,1,0,0,1,1,0,1,1,0,1,1,0,1,1,0,0,1,0,0,0,0,0,1,1,0,1,1,1,0,0,1,0,0,0,0,0,1,1,0,1} {1,1,1,1,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,1,1,1,0} {1,0,1,0,0,0,0,1,0,1,0,1,1,0,0,0,1,1,1,1,0,1,1,1,0,0,0,0}
{0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1}

Power off :Repeat all the above and change red sequence with this:
{1,0,1,0,0,0,0,1,0,1,0,1,1,0,0,0,0,1,1,1,0,1,1,1,1,0,0,0}

Westinghouse ceiling fan infrared control hack (UC7130T)

We have no header or "wake-up" pulse here. Logic "0" is a pause of 840us followed by a pulse of 420us of 38KHZ and logic "1" is a pause of 430us followed by a pulse of 820us of 38KHZ. After last bit we must wait for 15ms to send same sequence again. Each sequence must be send at least 3 times. Infrared sender must have a powerful output (multiple leds and/or high voltage (9V) on collector - darlington driver).

{0,1,0,0,0,0,0,0,0,0,0,1,0} FAN OFF
{0,1,0,0,0,0,0,0,0,1,0,0,0} FAN SPEED 1 (MIN)
{0,1,0,0,0,0,0,0,1,0,0,0,0} FAN SPEED 2 (MED)
{0,1,0,0,0,0,0,1,0,0,0,0,0} FAN SPEED 3 (MAX)
{0,1,0,0,0,0,0,0,0,0,0,0,1} LIGHT ON/OFF
{0,1,0,0,0,0,0,0,0,0,1,0,0} LIGHT SLEEP

INSURGENT DETECTION - MONITORING AUV

2011-09-05T05:55:00.000-07:00

This post has no comments

AUTONOMOUS - REMOTE CONTROLLED VEHICLE

2011-09-05T04:33:00.000-07:00

It s a simple implementation of ardupilot ver 1.0 with a few add-ons. FTDI usb to serial interface is used to program the ardupilot, an RF data link at 9600baud transmitts positioning and other data , and standard 35 MHZ r/c equipment is used for vehicle control and activation of autopilot. Oziexplorer is used as the logging and mapping interface (for real time position indication) via a simple trick : Distance to home (to launch point) is injected into GGA NMEA sequence instead of altiude (by regenerating the sequence and transmitting it via rf )

Unfortunately due to the complete lack of suspension and because of the ultra simple steering mechanism of the extremely cheap (6 euro's ) jeep model, when RTL (Return To Launch) function was implemented, it produced a funny track to home as shown in the last capture from Ozi interface.

The implementation of RTL function

AUTONOMOUS / REMOTE CONTROLLED WATER RESERVOIR SURVEY

2011-09-05T01:33:00.000-07:00

Another implementation of arduino micro-controller auto pilot is the lake surveying ROV . The main advantage of such an implementation is that ,the greatest percentage of lake area has depths less than 1/2 meter and so it's quite impossible to measure it using conventional depth sounding techniques.

A motorized (via a Graupner outboard motor) plywood platform on 2 cylindrical floats (catamaran style), with just 5 cm drought fits the task , with plenty of electronics on board such as:

A picaxe ESC (electronic speed control)
A standard 4 channel r/c receiver at 35 MHZ
An Arduino board with Em406 GPS
An intelligent depth sounder (with rs232 output)
A 433MHZ 9600 baud telemetry transmitter or an XBee pro link at 900MHZ.

and for the monitoring station:

A laptop that runs Winxp and Oziexplorer (my favorite mapping program)
An underwater camera with video link (for clearing underwater obstructions)
A laptop for data logging - real time position indication -video capture

Surveying ROV with Gps , Autopilot, RF data link and depth sounder

Quite a big team is required for such a project. You may need :

a 4x4 truck
a driver
a diver
a cameraman
a computer IT expert
an electronics engineer
a Photographer
a GIS expert
a computer graphics / desktop publishing expert
Logging , mapping , GIS , video authoring and Desktop publishing software
a sponsor

But the results can be rewarding as shown in the following images :

Survey results

REMOTE CONTROLLED KITE AERIAL PHOTOGRAPHY

2011-09-05T00:43:00.000-07:00

Aerial photography is implemented via an r/c kite - suspended pan tilt rig ,and an rf video link. Kite aerial photography is completely different from traditional r/c model photography. It has some serious advantages as :

Low cost
Low risk for environment, operator and subject
Completely portable. (whole set fits in a 40 lt backpack)
Easy maintenance.
Quiet and low profile.
One person operation , remote operation possible.

Main drawbacks are :

Wind must have a speed over 12 knots (>4 beaufort scale) - not a problem at the Aegean islands.
Kite line must be clear of electric lines, trees and other obstacles.

The kite can be a fully foldable one (no spars) of the flowform type but virtually any type with a 2-3m2 area can be used..
The spool (reel) is the most critical part of the system , because it must take 150-400m of line, it must have a kind of brake ( and that is very important!) and a handle that can wind and release the line fast . Mine is hand made of 10mm plywood.
The rig is suspended on a picavet style cross from the line below the kite (as a safety measure) ,it weights approx 500grams and it consists of:

a 2mm aluminum frame with 4mm ball bearings (from old floppy disk readers)
2 standard servos for pan and tilt (the pan servo must rotate 360deg )
A micro servo for the shutter button
an rf video/audio link at 1.2GHZ connected to tv out of the camera
a standard 3 channel r/c transmitter at 35 MHZ
A high resolution digital camera (>9mpix) in wide angle mode, low weight
Batteries for all the above

kite, profile

kite and spool

kite and rig

Ancient stone heaps , Χουβέλες στο Αίπος


Aquaduct over Koufos stream, Το υδραγωγείο στο ρέμα του Κουφού

Chios landscape , Ανοιξιάτικο τοπίο

Δότια Χίου , Dotia Chios

Byzantine tower at Dotia ,Chios . Βυζαντινός πύργος στα Δότια

Anavatos - Chios Ανάβατος Χίου

Here is a low-resolution video from the aerial camera.