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Hello everyone! This is the third blog post based on following table.

This blog explains the highlighted section in the overall architecture.

Sphero Maze on HCP - Architecture Part 3.png

The easiest way to implement this part is just buying ready-made maze and sensors then connect them to Raspberry Pi’s GPIO.

For the maze for Sphero, SAP Korea team chose MazeBot since it is easy to assemble and extend.

MazeBot.png

We bought 6 MazeBots and assembled them as below.

Assembled MazeBot.jpg

For sensors, you can use any type of sensors such as infrared, pressure, light, vibration, water and so on as long as those can be connected to Raspberry Pi via GPIO.

SAP Korea team chose infrared sensors which is generally composed of transmitter and receiver.

For your reference, there are many ready-made infrared sensor kits available as below.

MagicW Digital 38khz Ir Receiver 38khz Ir Transmitter Sensor Module Kit for Arduino Compatible

Pack of 2 Digital 38khz Infrared Ir Sensor Transmitter Kit for Arduino

However, since SAP Korea team would like to embed infrared sensors in the wall of the maze, we decided to make it by ourselves.

So, if you would like to follow exactly what we did, you need following things.


Prerequisites

  • Mazebot (6 EA)
  • Receiver (16 EA)

– 19×10 Epoxy Breadboard (16 EA)

– Photo Transistor ST-7L (16 EA)

– 20K Ohm Variable Resistor (16 EA)

– Red LED (16 EA)

– Round Socket (16 EA)

– Female Connector (16 EA)

Receiver.png

  • Transmitter (16 EA)

– 19×10 Epoxy Breadboard (16 EA)

– Photo Transistor EL-7L (16 EA)

– 50 Ohm Resistor (16 EA) – It depends on the distance between Transmitter and Receiver

– Blue LED (16 EA)

– Round Socket (16 EA)

– Female Connector (16 EA)

Transmitter.png

  • Power Hub (Many)

– 11×3 Epoxy Breadboard

– Pin Header

– Wire Cable

Power Hub.png

  • Male Connector (32 EA)
  • Many Jumper Cables
  • Many Wire Cables
  • Many Jumpers
  • Many Heat Shrink Tubings
  • Epoxy Breadboard
  • Soldering Kit

Schematic

For whom with Electronic Engineering background, here is the schematic.

Schematic.png

Soldering & Assembling

And the followings are some photos during soldering and assembling.

Soldering & Assembly 01.png

Soldering & Assembly 02.png

Soldering & Assembly 03.png

Soldering & Assembly 04.png

Through above work, we created baseline for 16 pairs of infrared sensors as below.

Soldering & Assembly 05.png

Soldering & Assembly 06.png

In order to embed each sensor to the wall of maze, we made 2 holes on each wall block as below.

Assembly 01.jpg

Assembly 05.jpg

Assembly 06.jpg

Then we prepared cables as below.

Assembly 07.jpg

Yellow one is for signal communication to Raspberry Pi’s GPIO but red and blue are just for power supply. And only receivers have yellow cable.

Assembly 12.jpg

Assembly 11.jpg

After embedding transmitters and receivers into the wall blocks, we connected photo transistors respectively as above.

Assembly 13.jpg

We also prepared 16 yellow extension cables with alphabetical order labels (A to P) as above.

Then we did our first test by connecting Raspberry Pi and power supply based on the maze map we prepared as below.

Maze Map.png

Assembly 14.jpg

The reason why we used bottom side of the maze to test was for easy wiring work.

Assembly 15.jpg

Ta-da! In this step, we quickly checked all sensors were working correctly with blue and red led.

Assembly 16.jpg

Assembly 17.jpg

After the first testing, we prepared infrared signal bus part as above to ensure stable connection to Raspberry Pi.

Assembly 19.jpg

Assembly 20.jpg

Then we did some wiring work as above.

Assembly 21.jpg

Assembly 22.jpg


Then finally, we made a black case for infrared signal bus and connected all cables. That’s it. This is all about hardware part.

Let me get back to you soon with Python codes to get signals from those sensors.

Best,

Joon

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