So I ordered some evaluation boards (about 100€/pcs) for me and two collegues who are studying with me at the NTB. Our goal is to have fun with wireless applications.

The RN-131 GSX Module is a 802.11 b/g wireless LAN Module with a lot of features – Details see datasheet.

If you already have a GSX Module you can use my LabView source below to show the UDP packets which the module sends in default configuration every 7 seconds.

The packets include

• MAC address of AP
• WiFi-Channel
• RSSI (quality)
• local TCP port
• RTC (real time clock value)
• NTC temperature option (if temperature sensor connected to module – otherwise sensor 7)
• Spare sensor reading
• ASCII time
• Version string with date code and Device ID string

This information can be used to open a TCP connection to the module or to configure it over WiFi. The module has to be in the same subnet as your PC or MAC if you want to receive the packages.

Here are some pictures of the Module in action:

Here is the LabView (8.6) Source as LLB: wifly-monitoring-distribution

In the last weeks I thought about new projects (beside the Mikrokopter project). So I started to study Objective-C programming by myself to be able to code iPhone applications in future. A good start for doing that is the book “Cocoa Programming For Mac OS X” by Aaron Hillegass.
A good podcast to start with Objective-C from the real basics is also this one from Peter and Ingo: http://0×02100.silutions.de/blog.html
Another good resource that I am using is the Stanford iPhone programming course, which is available over iTunes U and resources to the course are here: http://www.stanford.edu/class/cs193p/cgi-bin/index.php

Because the SPP Bluetooth profile is currently not supported by the iPhone (OS 3.1), data transfer has to be done over TCP/IP or some other “frickel-ware” tricks (Audio, Display and Camera, other BT-profiles, …).

So I have to put some energy in the field of embedded wireless webservers, TCP/IP protocol, debugging connections, snif packets, make connections from iPhone to an embedded (web)server and so on.

Today I did a first test with servers. I started a Java Server on the PC and connected to that server over telnet from the Mac mini in my local LAN over WiFi. All Bytes that are received by the server are displayed in the console. With the ESC Symbol transmitted from the Mac, the connection can be closed.

Here is a screenshot from the final console outputs and the sourcecode for the Java server:

Java on PC, telnet on Mac

Sourcefile server.java; Required Class out.java

Thanks to Adam B. for showing me how easy it is to code a server in Java.

ToDo’s for the next months:
* The Java console should display a connection which is established by an iPhone app.
* The Server should be an embedded WiFi server -> order an embedded WiFi module.
* Get practice in Objective-C programming, continue Stanford iPhone course
* Realize the path: iPhone (Simulator) -> embedded WiFi server
* Let some LEDs blink, dependent on the orientation of the iPhone (Simulator)
* Let some LEDs blink, dependent on some buttons in the iPhone App
* Pay the developer license fee to start developing on real iPhone hardware ($100)
* Having fun and thinking about nice tools of iPhone Apps together with embedded controllers

Greets,
Speedy

Yeah, it’s summer and now I have time to continue my investigations in FPV-flying. Some weeks ago I had a little disaster and crashed my FlightCtrl and my NaviCtrl (shortcut in the connection cable).
So I had to order a new NaviCtrl immediatly. I had luck, the MK-GPS and EPI-OSD survived.

And now – my Kopter is back (better than ever *ggg*)

Ok, let’s get to the topic.

A lot of people asked me, how I mount the camera and the EPI-OSD on my Mikrokopter. Thats a little bit complicated to explain and so I took some pictures to show you how I did it.
Update – 30.05.09: Attention, if you want your C-OSD Version to work fully together with the NaviCtrl you have to connect the EPI-OSD to the debug port of you NaviCtrl!

I hope that I will have some time in the next weeks to do my first FPV Tests with video recording to post it here (maybe the weather is nice

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Greetings,
Speedy

Here is a short clip of the actual status. Details will follow at the end of the project.

Some facts:

• Robot controlled by WiiMote
• A PC/Laptop has a relay application that realizes the Bluetooth communication (Software: LabView)
• WiiMote -> Bluetooth -> Labtop -> Bluetooth -> uC -> Motors/Sensors (Bidirectional of course)
• IR-Sensors (Sharp Type GPD120)
• Stepper Motors
• LiPo power supply (11.1V / 3p1s)

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Open tasks (“todo”)

• give it intelligence (autonom)
• communication with partner team
• final documentation
• preperation for public presentation

Speedy

In the last days i tested the new version of DUBwise (Digital UFO Broadcasting with intelligent service equipment – coded by LiGi). The Kopter is connected via Bluetooth to the mobile device. In my case this was a Sony Ericsson W810i.

The actual Version has the possibility to adjust all Settings (like the MK-Tool) and nice features are the Graph indicator and the Cockpit which displays a virtual horizont.

It’s a amazing tool and supports a lot of mobile devices. Ligi is also updating and patching all night long to be in sync with the latest released Software from the Mikrokopter project itself (FlightCtrl, NaviCtrl)

The tool is also able to talk and tell you how full the Lipo is (Voltage). Other nice informations are the number of satellites, height over ground, heading, distance to home position and so on…

To see how the tool looks in action here is a short clip:

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Details about the project you can find at  http://www.mikrokopter.de/ucwiki/en/DUBwise or http://www.ligi.de

Update 14.04.2009: Because some guys asked me how to install the application on their mobile phone, here is an instruction. For the installation you can use the “Installer” from LiGi (http://ligi-tec.blogspot.com/2009/03/dubwise-installer.html).
If you have no internet connection, the installer shows you which file you have to install for your specific device. The sources and binaries you can find here: http://svn.mikrokopter.de/mikrowebsvn/listing.php?repname=Projects&path=%2FDUBwise%2Ftags%2Fv0.52%2Fmisc%2F#_DUBwise_tags_v0.52_misc_

Finally I finished the first semester of the NTB in Buchs.
Beside working for my company I had to learn a lot – but – I also had some time to combine the requirements for the “robot” project in the first year with a possible nice feature for the Mikrokopter.

I’m talking about the “traditional” IR (infrared) distance sensors from Sharp. There are different types of them, for example: GP2D12, GP2D120, GP2Y0A02YK (GP2Y0A02)
These three types are sensors that have an analog output (there are also other sensor-types from sharp with adjustable or fixed digital outputs)

The sensors have a very simple interface:

• Power Supply
• GND
• Analog Out

That’s it!

The difference of these three types that I tested is the measuring distance or let me say their “sensitivity”.

For example the GP2D12 specification is:

Range: 8cm to 80 cm
Supply: 5,0V;
Vout: 0,4V bis 2,6V typ. (80cm – 10cm);
Current: 33mA typ.

Typical feedback:

As you can see the output voltage is not linear to the distance – but that is not a big problem for the softare, if you know that behaviour

The GP2D120 if from 4cm to 30cm and the GP2Y0A02YK is from 20cm to 150cm.

One Measurement cycle:

The principle of the measurements is alwas the same. The IR-Led is driven by the sensor electronics to send 32 pulses. The electronic is then measuring the response of the receiving circuit and setting a output voltage, equivalent to the measured distance.
That means that you have a analog signal that updates its value about every 40ms.

Startup:

Be aware that the sensor needs some time to get the first “serious” output (about 60ms). Here is a startup plot of the GP2D12 with a obstacle in front of it.

Measuring sequence in detail:

One measuring pulse in detail:

As you can see in the picture above you can see that the sensor needs about 220mA for each measuring pulse. So the power supply sould be designed to filter such short current spikes. In average the current consumption of these sensors is ok.

I have made a short video of the tests that i have done with the AVR-USB-uC board, connected via UART to the PC and visualized with LabView.

More tests will follow…

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Maybe one of these sensors (or a combination of mutiple sensors) can be used to assist the Mikrokopter at automatic landing.