ZMR250 with D4R II

D4R II range problems, acting all of a sudden

Today, I have had some spare time and I have decided to go and fly few battery packs on my favorite spot.
Everything seemed OK while I was flying the first pack and when I started the second after a minute or so my Taranis started blabbering telemetry lost/recovered. I have landed and checked all connections, antennas the D4R II receiver and so on but everything seemed to be in order.

Well, that was odd, but I have decided to continue flying since I have wasted only one pack. I have continued flying and ignored the warnings up till a moment when I have lost signal completely and the Naze failsafe kicked in and my miniquad started falling as a rock.

Enjoying the sunset over Skopje, the moment when my D2R II receiver started acting.

Screenshot taken just before the failsafe on my Naze kicked in

Up side down. D4R II acting strange.

Aaaand one second after that. It would have looked more scary to me if this was the first time that my quad is up side down 🙂

Luckily enough I was flying relatively high at the moment and the link got restored, so I have had more than enough time to stand up and see my miniquad falling and then again look at my monitor (no goggles here), flip it over and continue flying.
I flew the rest of the packs in closer range noticing that something is definitely wrong, either with my transmitter or the receiver on my miniquad.

When I have got back home, I have tested the range just to see that the RSSI signal was dropping to zero when I entered another room with a concrete wall between the transmitter and receiver.

I needed to check if my Taranis is OK first, so I have turned on my bigger quad with X8R on it and walked with the transmitter between the rooms without any issues, the RSSI signal was between 60 and 90. So the Taranis was  functioning perfectly.

I have removed the D4R receiver from my miniquad and powered it with a spare ESC so I could test if maybe there is some interference that is causing the problem. Still the RSSI signal dropped to zero when moving in the other room.

Next thing that I have got on my mind was replacing the antennas on the D4R with new ones, that didn’t help either.

I had no other ideas so I have tried googling the problem. No luck there too.

Replace D4R II with X8R

X8R replacement receiver

At the end, I was ready to give up and replace the receiver with my spare X8R, so I have bound  it in place of the D4R and I have created new model for the D4R just in case I needed it sometime in future and once again, for the last time I have tested the range, just to discover that the range problem was gone and my D4R receiver displayed RSSI values similar to the ones of the X8R.

So it seems that there was some kind of linking problem between the Taranis and D4R II and when I relinked them in order to use it with the new model, the problem was gone.

After this, I have once again linked the D4R with the ZMR250 model in the Taranis and everything worked without any issues.

My two cents, if you experience similar problems, try rebinding the receiver with the transmitter, it may save you some time and possibly $$ for a new receiver.

Duplicator I3

Adding a Glass Build Plate to my Duplicator i3 3D Printer

I have had my Duplicator i3 for about two months and so far I have been printing with PLA. I have been thinking of adding glass build plate so I could try to print with ABS  filament. ABS requires higher nozzle and build plate temperatures and I was not sure if the sticker could handle that without melting.

Duplicator I3
So, after doing some research on google, I have found that I have to remove the sticker and I have ordered a plate of borosilicate glass from here.
If you own a Duplicator i3, check this  regarding the dimensions and the whole process. Please note that the article is for the older Duplicator version, and there is no sticker over the aluminium build plate.

The item arrived in more or less regular time of one month, well packed and protected with a “Fragile” sticker on it.

Borosilicate glass and paper clips

The glass and four paper clips to hold it in place. Some of the Di3 owners are sticking the glass to the build plate. I have decided to try with paper clips first. Please note that in some cases the clips may interfere with the nozzle or the y axis movement.

Duplicator I3 - removing the sticker

Removing the sticker. It came up relatively easy, but there was a lot of glue left on the build plate.

Duplicator I3 - glue left on the build plate

It took me almost an hour and a bottle of my wife’s acetone in order to clear the glue. I haven’t tried but it may help heating the build plate before removing the sticker.

Duplicator I3 with added glass build plate

Finished cleaning the glue and addint the glass build plate. The binding clips are placed temporarily. If placed like this, the ones on the left side are interfeering with the nozzle head movement.

I needed to lower the printing bed in order to account for the glass plate height. There was enough room to accommodate the glass plate and the springs weren’t contracted all the way. If the glass plate was thicker I may have had to raise the Z axis end stop.

Duplicator I3 - printing on the glass build plate

Printing sample on the glass build plate in order to precisely level the build plate. The left side needed to be raised and the right side needed some lowering.  Note the binder clips in the middle of the glass plate and the handles removed since they were touching the printer frame. If you plan to do this, buy different sizes bind clips so you could try which will fit the best.

Follow me

Photo safari in Ohrid

Our vacation in Ohrid was nearing its end so for the last day I have decided to go on a photo safari and try to take some beautiful photos that represent this pearl of the Balkans in its best light.
The weather was beautiful, and promising for the photo safari.

Famous Ohrid architecture

I have decided to go from the walkway by the Ohrid lake and continue trough the old town.

Ohrid old town

The Epiphany holiday was nearing and the visible signs were all over the city.

St. John Kaneo

When walking trough Ohrid, it is really hard to miss one of its churches.
According to Wikipedia, Ohrid once had 356 churches, one for each day of the year, and has been referred to as a “Jerusalem (of the Balkans)”.

The bridge of wishes

There is always a new angle, a new perspective to take photos at the same spot visited plenty of times. A great possibility to fill your lens with beautiful scenes of the old Ohrid architecture, the lake, the churches…

Photo safari by the Ohrid lake

I knew from the start that this will be a whole day photo safari, and I was counting on that so I can have my lunch in one of the beautiful restaurants on the shore of the Ohrid lake

Potpesh restaurant

Potpesh restaurant – really nice place to have a lunch or a coffee and rest a bit

ending the photo safari on sunset with magnificent landscape photos of the lake and the old town

Ending the day with a spectacular sunset  landscape of the lake and the old town.

Feel free to contact me if you intend to visit Ohrid and need additional info.
If you want to see some more photos that I have taken during my stay in Ohrid, visit my 500px profile or my Facebook page.

Revisit with my ZMR 250

I have kept my battery packs full, waiting for the right moment to go and fly at the same spot that we have visited few days ago. I have been using ZMR250 and mobius for aerial photography for quite a while. I love the portability of the ZMR250, everything fits in a really small backpack and that enables me to reach most remote places.

It was raining most of the day, but it suddenly stopped and the sun came up so I have grabbed my gear and rushed to just in time to see the sunset.


I have decided to fly at two locations that were close enough to fly from one spot to the other but in order to save battery life I flew one pack at the first spot and then moved to the other one.

Ohrid lake aerial photography

Although most of the people doesn’t like the fish-eye distortion these small wide angle cameras produce, I have found that sometimes the effect could look really interesting when used for aerial photography.

Land and water division - aerial photography at Ohrid lake

It was windy, but nothing that my miniquad could handle. You could see how much I had to lean it to the wind in order to counteract its force.


Aeriall photography - old boat stranded on the shore of the Ohrid lake

The boat was still there, at the same place. This time, I have decided to take some photos from another angle since I liked the colors of the sky reflecting in the lake.

Lake panorama

The end of another beautifull day spent in Ohrid.

You could check the whole gallery here. Having set my Mobius to take pictures each second, it is really hard to pick the right ones among 907 photos.

Using node.js and Xively with Arduino Mini Pro to graph motion sensor data

Before you start reading this article. This is not a tutorial, these are my documented findings while tinkering with Arduino, I have much to learn having in mind that I have been playing with these toys for a couple of days.


Arduino pro mini with sensors

Recently while visiting my good friend Igor Stamatovski, I have told him that I plan to build an air quality measuring device and that I have already ordered several items from Aliexpress. I have also told him that I’m anxious to get them and start building it.
Instead of replaying he got up and started going trough the things in a drawer on his work desk.

When he returned on my surprise he handed me an Arduino pro mini along with a dozen of sensors.
I have had a previous basic experience with Arduino based electronics and I already knew how to upload a sketch with FTDI  because I have previously owned a MultiWii FC and also I had tinkered with a SimpleBGC gimball controller with a broken usb port, but I had no idea on how to connect sensors, get sensor data  etc.

So I thought, let’s start with something basic, like just getting the sensor data from a motion sensor.
That was really easy since there are plenty of sketches that can help you get things going. I have encountered only one problem with the pinouts on the sensor since the writing on the board was covered with the plastic sensor casing. After sorting that out, I have the sensor data readouts in the serial monitor.

Sketch screenshot

Screenshot of the working version in its final phase. Nevermind the code cleanness, this is v0. my only goal was to make this work. You can download the sketch here.

My next thought was, ok, I have the data in the serial monitor, but I have no use of it at the moment, I will need a way to at least have that data readout on a local web server.
Using the Arduino pro without a wifi shield, the only way to get the data is by using the serial port. So I needed something that could access the serial port on my computer, read the data and display it on a webpage. I know that if I had wifi shield the things would have been much easier, but I had to work with the parts that I already had.
After doing a short research on google, I have found that node.js fits the task perfectly.
Now I have a knowledge of JavaScript, but I have never had a chance to play with node.js. Luckily I have found this tutorial. Please note that the GitHub link is not working, The correct one is this.

node.js server displaying the app

By following the tutorial and slight modifications in order to get it working with my sketch, I have managed to get the data displayed on a local web server.  I have also added two buttons on the webpage that will request data and stop the request when we don’t need it, this is acting as an arm/disarm switch for the sensor. This was previously  done automatically on client connect/disconnect.

Next step, graphing the data, displaying when the sensor was triggered.
I was looking for an IOT solution where I could send the data and have a graph and I have decided to go with the personal edition of Xively since there are a lot of people using it already and it was really easy to send the data by using Jquery and the provided JS library.

Xively live data displayed
And finally, each serial event will post data on Xively and the graph will display values varying between one and zero.
If you are interested to try this experiment, feel free to download the source files here.

Home, home again. I like to be here when I can

It’s really nice to be home. Doesn’t matter if the weather is good or bad, we could just go out and feel the fresh air, the one that we are missing while living in Skopje.
Most of these photos were taken by the Ohrid lake where we went for a walk after visiting the church of St. Stefan

The lake is a source of enormous inspiration for me. I can’t stop taking photos.
I have left my camera at home and I have used my old trusty N7100 phone to take these pictures.

Found this boat stranded on the shore while walking by the lake. Probably the owner lives somewhere on the other side of the lake and the boat floated here during a storm. A short inspection proved that I was right, the boat's bottom was full of holes and it seemed that it was stranded here for quite a while.

Found this boat stranded on the shore while walking by the lake. Probably the owner lives somewhere on the other side of the lake and the boat floated here during a storm. A short inspection proved that I was right, the boat’s bottom was full of holes and it seemed that it was stranded here for quite a while.

My ZMR 250 all packed up and ready to go

Sadly enough I haven’t got my zmr 250 miniquad to capture some aerial photos, but I will revisit this place once again since I have found a really great spot for flying that involves a nice tree park and a deserted building.