The next important thing was to give the robot more personality and I found one or two chaps in the internet that worked on LED matrix eyes. But I also wanted to get computer vision to Omnibot so that it could see things or people and potentially speak to them, grab them or move towards them.

So let’s start with the decomposition of the original eyes which basically had a little lamp build in:

I decided to just keep the head plate and the black adapter and replace all other parts. Next I soldered the two 8×8 LED matrices, they are chainable and adapted the code from the above link.

This was very satisfying as there was a quick success. However, as you can see, the MAX7219 controller chip is standing out of the black adapter, making it impossible to build the eyes into the adapter. So the next iteration was to desolder them again and rotate them 90 degrees…

I also decided to design a 3d printed adapter to keep the squared matrix in the round hole.

I also had to connect the two LED matrices differently as the pins would look downwards now. I decided to use a perf-board that I had in my cupboard from since my teenage years, so it would match the Omnibot in age 😀

A little software experiment yielded this:

When I was working on the Omnibot’s eyes, the high resolution Raspberry Pi cameras were launched and I had to buy them immediately. I don’t really like the flimsy design on the original Pi cams.

I decided to use the fish eye lens as it is small enough and would broaden the Field of View of the Omnibot.

I realised that the original black Omnibot adapter certainly has no hole for the objective, but I definetly wanted to have the camera very close to the LED eyes. So I decided to do away with the adapter altogether and re-designed the whole adapter to keep the objective as well. This was not too easy as the diameter is really huge and I wanted to keep the matrices at a maximum in size.

Finally, I also had to match the PCB with the matrix PCBs which also was not too easy. But luckily, it worked out:

Finally, I had to buy a longer cable to connect the camera to the Raspberry Pi that was mounted on the Omnibot 5402’s tape recorder base plate in the meantime.

So, finally, all pieces come together in under the dome of the head part. The dome is dimming the picture a bit, so experiments will show whether computer vision works well enough. The manual focus of the Pi cam is helping here.

See the currently final setup here:

here’s a liquid magnetic display by ferolic around a really bright guy named zelf koelman:

i was immediately fascinated by the organic movements of the drops and my brain couldn’t stop thinking about how to build one. we know magnetic particles from adaptive dampening in cars and we also know liquid displays as well as e-paper that turns pixels by a little magnetic current.

so this display is a combination of these and my feeling is that the display consists of little electro-magnets and some fluid that contains magnetic particles in oil. the trick has to be that these particles stay together.

i would guess that each pixel is one magnet that can be controlled individually, i thought this would be four seven segment digits with two mangets per line, i.e. 4x7x2 pixels = 56. then you also need some pixels to lift them from the soup at the bottom, for example 10 or so that would be 66. on the other hand you see that this is a full pixelated display, so if they are using 10×20 pixels, that would be 200.

first of all i did some research on the magnetic material called ferrofluid invented by NASA: “Ferrofluid was invented in 1963 by NASA’s Steve Papell as a liquid rocket fuel that could be drawn toward a pump inlet in a weightless environment by applying a magnetic field.” again, this interesting connection to my first association to the automotive application. it seems that these two materials are different in their properties due to their particle size though.

anyway. quick search on google yielded an article on instructables: 

 

 

 

 

 

 

 

 

 

 

interestingly, they also cite a project by martin frey in berlin:

next, we need some cheap and small electro-magnets, here are the cheapest & smallest, i could find on ebay:

two centimeters of diameter. i’m sure there’s something cheaper than 4.66€ because that would lead to 200×5 = 1000€ for the magnets.

finally, we need an arduino i would guess that either you use a nano with pwm per line, i.e. 10 ports, or a mega 20 pwms per column. finally, we need some shift register, for example this little guy: 74HC595, there is plenty of projects using it together with arduinos to drive LED matrix displays. for example this:

 

this would be a really nice project, would love to do it maybe during the christmas holidays. any further suggestions?

 

um herauszufinden, wieviele leute der ausgang von germany’s next top model interessiert.