Let's Make Robots!

The Stray

Not sure yet
compound_eye.zip1.7 KB

I started an new robot project which will be a long time project. The base is the 4WD chassies with 4 gear motors.

The first stage is to attach the Dagu IR compound eye on the pan tilt set in front.

There will be one or more ultra sound sensors or infrared sensors to check the proximity.

My first choice for the brain is the Dagu Spider controller since I probably need more I/O pins than a Arduino Uno/Duemilanove can provide.

To keep in touch with the robot car I will use the mini Wi-FI router TL WR703N running OpenWRT

Equipped with an USB host port, an ethernet port (RJ45) I am able to attach a webcam directly to the router and send the stream to the network. The cable you see in the picture is already attached to the TX and RX pins of the router. Right now I am trying to figure out all possibilities to connect the router with the Spider controller or/and witht the network.

Also I will include a remote controlling program which will be activated and override the autonomus programming (not the self protecting behavior) as soon as the bluetooth is receiving a "go".

Additional the robot will seek light and charge the batteries when moving or resting. I am working on a solar tracker and will attach it to the chassies when done and working.

Wheel encoders, a compass module and other methods to measure his location, maybe a gripper and still not yet known things will be part of the robot with no name the name "The Stray" :-)

UPDATE Sep 10:

Since I was busy for weeks (Campus Party, Project ALF & Swarmbots in our local hackerspace) and also have a family the "Stray" was collecting dust. Now I reactivated it and working @ a solution for the compound eye. The first code gives me already some good output which I still have to convert to servo movement (right now it's just outputted via LED's for debugging) -> Yeah I love those LED's for debugging...even that I got two LCD's lying around :-) Code and pictures will follow.

UPDATE Sep 11:

I got the compound eye is attached to the servo mount now (Note to myself: Need to find a better solution since the servo stays upright and the eye should be mounted horizontially). The code I used is this one: Arduino code for DAGU compound eye (thanks A1200, i grabbed the code and attached it to my project in case something happens with your comment there). Why invent the wheel again. This code is working for my setup just fine (maybe need to tweak that for my needs later). As the brain I used the DAGU Red Back Spider Controller, a very nice piece of a board.

The eye on the servo pan tilt mount is performing good. Movements with hand are not that stable but a piece of paper or a carton causes a very stable and smooth movement.

NOTE to the CODE: OddBot told me that the code is not complete. I will later update the file with the original code from OddBot's Mr. General.


This weekend is time to proceed with the Stray. Now my first Aluminium work on a robot. I built a case for the DAGU compound eye. As pictures says more than a thousand words, here you go...

Cut from 1mm Aluminium sheet ( a bit too thick for my opinion)

Sanded the sharp edges after cutting.

Used tools so far.

To bend the short side I used this tool. The long sides I bent with the vice (sorry, no picture)

Drilled the holes with a Dremel like tool and attached the whole thing on the pan tilt mount. The standoff's are for the compound eye.

The cutout in the bottom is for the pins, as you see in the next picture.

Compound eye is safe in the box now.

For my frist Aluminium work after decades I need to improve my skills. Better taking care of the bending edge since this radius has to be added when cutting the piece. Now the LED's are looking out but the plan was to keep them "inside" the case.

I kept the plastic coating on the inside for insulation reasons.

UPDATE 2 Oct 7:

Di still some soldering today. Started with the motor driver board. It will contain two L293, one for the two motors on each side, somefancy blue LED's (just to indicate that the motors are running forward), a 5V regulator L7805 and the header terminal is for a LCD with not yet decided data output.

Upper side with some of the components. 2x L293, 1x L7805, 2x LED blue wth resistor, 1x header terminal for LCD.

Bottom side (not that interesting as it's not finished yet).

...to be continued...


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Tip: you don't need to take care on the bending radius if you bend the aluminium always to the side where you made the marking lines. Mostly something must fit in a box, not the box in something else :)

Got it Markus, but what I mean is that the radius has to be added to the lenght of the side which you bend, so that it's long enough after bending...

You don't need to consider the bending radius if your marking lines refer to the inner sizes of the box you want to have.

Bend it then in this way (sides up). The inner bending radius is much smaller (can be neglected for such thin aluminium plates):

If you bend the sides of the box to the opposite direction (down), you getting sides which are around 1.5 mm lower than you wanted.

I see now...

Hehe, I got the wrong assumption. Thanks Markus, will try this today again :-)

Wow, I didn't know this low-cost router !

That's cool since openwrt can be uploaded and according to http://wiki.openwrt.org/toh/tp-link/tl-wr703n , it draws only 100ma after boot.

The serial on the router could be used to interact with the arduino directly (using shell scripts ) thus expanding space for code ! I guess robots could easily carry the router and use it as wifi clients communicating with other AP, this could replace the arduino wifi shield.

Very nice projet, thnks  !!!


Right now I am just calibrating the compiound eye. Later I need to install the DAGU Spider controller and the motor controller. I guess the router will be one of the next tasks after that, maybe hacked with an WR-703N extention board

TL WR703N running OpenWRT looks very popular with its tiny size and interface ^_^

Yes it is. I hope to find a bit more time to learn more about this OpenWRT. The size is really perfect for the use in our robots and the functionality can be improved too.

Might I ask where I'd find those servo brackets you used?

The brackets are from taobao.com