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My question is on sensors, camera (image algorithms). I am looking into the field of robotics and am wanting to construct a track (path) for a machine of some sorts to traverse along. I have successfully simulated goal potential and obstacles in a program. Now I would like to do the same with a physical "robot" and a road like path laid out in white tape or something similar. The tape is to simulate a boundary that must not be crossed.

My question is what sensors should I invest in in order to to track white tape or something similar? Could I use a camera and some image algorithms? If so can someone point me in the right direction on hardware (sensors) and software (which algorithms that can be applied)?

Many thanks

Saad Attieh
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1 Answers1

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I think this is more suited for electrical engineering or robotics sites ...

Anyway the answer depends on level of your HW and programming skills.

  1. Control unit

    I recommend to start with some MCU with GPIO,PWM,DAC,ADC,SRAM at disposal and no need for too many supporting parts. My choice for this would be Atmel AT32UC3L064. It does not need crystal has 64KB of SRAM for your use and have many features ... Datasheet says it runs on max 66MHz so computing power is more then enough. It can be programmed by ISP with use of RS232 serial port + voltage changer to TTL like max232 + FLIP without need for any expensive programmer ...

    AVR studio is free and capable of C/C++ (my favourite version is 2.7 the newer ones are ugly).

    The only problem is TQFP package which is a bit tricky to handle on PCB but still doable in home conditions.

  2. Sensors

    From start I would avoid camera unless you are familiar with interfacing it. I would start with LED/Photo-transistor pairs capable of detecting your tape the wavelength depends on your maze conditions usually IR is used but you need to check if you can detect your tape reliably from the background. Set the LED to shine on the floor in scanned direction and set the photo-transistor so it can detect reflected light from it.

    if you want to port to 3D maze then use Ultrasound Transceiver/Receiver pairs. All of the analog inputs must be transformed to proper voltage level by operational amplifiers and or resistor dividers.

  3. Actuators

    if you need speed and low power consumption use BLDC or DC motors. For BLDC you need a proper driver/regulator (like zero crossing) and DC motors need just (half)bridge or Transistor array. For slow but precise motion use stepping motors where turning is usually achieved by using 2 motors one for left side and one for right side then turning is achieved by driving the motors to different rpm ...

    All induction/overvoltage unsafe pins should be take care with diodes/zener diodes/transils to protect MCU and also to improve power consumption. Well placed diode returning inductive currents back to main power supply can lower average power consumption of motors by 30% !!!

  4. Programming

    Start with movement commands/modes/states (PWM,command que,timers/counters) when you can move at will then start coding the sensory interfaces. Motors can influence the sensory input so measure in times when there is no or at least lower noise. Send measured values to some test pins as a PWM to visually check the results on Oscilloscope. If you do not have one you can use mine or any other LF from soundcard

    in my second comment there is the link to the win32 apps but take in mind it is usable only up to 20KHz only...

    When you have all subsystems working as expected then you can start coding the actual logic behind route/line follower or maze solver ...

[Notes]

There are SDKs for most MCU chips out there so try to find one including all electronics you need. If you are lucky you can avoid making your own PCB and circuit which can be a big problem if you lack the knowledge and experience.

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