Building a home robot: Part 7 - the front RGB LED display

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A Raspberry Pi touchscreen is used to show Rooberts face. So it can´t be used to show status information like battery state or the “feelings” of its python finite state machine.

Fortunately the body front was still missing – so this seemed to be a good place to mount additional optical output.

I tried several small LCD- and OLED Displays, but they didn’t please me.

In the end I used an 8x8 Neopixel array, a 24 Neopixel ring and a 1 Neopixel lighted big button.

In the beginning the 8x8 pixel array was too bright to see the 8x8 pixel as one image. After attaching a 3d printed cover it looked like quadratic pixels.

The python code can read a GIF file and display it on the 8x8 pixel display. When in idle mode, Roobert shows a beating heart GIF.

The outer ring of Neopixels shows the battery state when driving around and the buttons Neopixel glows up when it seems to be a good idea to press it now.

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Building a home robot: Part 6 - the 3d room sensor

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The built in Roomba distance sensors can´t prevent damage when driving around because Roobert is larger than the original vacuum cleaner. My first idea was to use an old Microsoft Kinect sensor. This worked very well – even the usage in python.

But the battery power went low very quick when driving around the first times. So I needed a solution without such high power consumption.

For this I used an ultrasonic distance sensor and two mini servos.

The servos can move the sensor on x-  and y- axis – like a 2 dimensional radar system.

The detection speed is slower than the Kinect version and depends on the chosen resolution: It can reach 2 FSP when using 4x3 measure points.

Just for fun I tried a resolution of 30x20 points. That takes 10 seconds for a frame but I was impressed how well you can “see” the shapes of obstacle objects.

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