[HeRos] Decisions

Hi everyone!

Today was a good day! We’ve decided what it is that our HeRos will do exactly.

– in “normal” mode: each HeRos is controlled by a user via smartphone. We’ll stream via WiFi what the camera sees directly to the smartphone (by WiFi Direct or normal WiFi, we don’t know yet). There will be no video processing after all, because the WiFi bandwidth will be enough to stream video, and the HeRos’ autonomous mode won’t be what we initially intended. The basic shots will be done with an IR laser diode, the 360° shots (and healing) will be done with an IR emitter under a diffusive dome at the top of each robot. Each robot will also have four “targets” on its surface (IR sensors with diffusive dome to increase target area) at which a direct shot has to be aimed and 3 large angle IR sensors that will detect proximity 360° shots or healing.

– in “berserk” mode: a robot can be set in this autonomous mode: the camera is turned off, and the robot isn’t controlled by a user any longer. Instead it roams the battlefield pseudo-randomly, avoiding obstacles along the way (with infrared or ultrasonic sensor, haven’t decided yet, which is better in your opinion?). While it moves, it regularly shoots a 360° proximity shot and long bursts of direct shots (IR laser diode) without aiming. For short periods of time, the 360° shooting turns into 360° healing. Basically in this mode the HeRos turns into a moving mine.

– the secondary modules will be small components containing only one element: a magnet. When “plugged” into the HeRos, each magnet will be detected by a Hall effect sensor. Our vision is: three different slots on the surface of the HeRos, each slot corresponding to a level of power: low, medium, high, and each slot having a different shape. In each slot a module of the right level (i.e. a module that fits) can be plugged. Depending on the orientation of the magnet within, it is (and is detected as such) either a defensive or an offensive module. The info from the hall sensors is then sent back to the phone and corresponding abilities are unlocked for the HeRos.

We’ve been looking for the right components to do all this (especially a camera whose DMA can connect directly to the SPI to feed the WiFi module) and we’re still looking for the right moving base (the pololu doesn’t allow us to implement odometry so we have to look for something else).

We’ve also prepared for tomorrow’s presentation of the project!

Until next time!

11 comments to [HeRos] Decisions

  • Alexis Polti

    What do you mean by “IR laser diode” ?

  • Alexis Polti

    When using this type of diode, you’ll need either a precise current controlled source or an external cicruit to monitor the diode current based on the photo-diode output.
    IMHO it would be much simpler to shoot with a directionnal IR LED (not laser, just of conventional IR LED – with a focalising lens if necessary).

  • BigFatFlo

    Ok! We leaned toward laser because the lowest angle for an IR LED we could find was 5°. But with a focalizing lens, it should work!

    On another note, where could we find a “diffusive dome” for the IR emitter for the 360° shots, and for the IR targets? Does it have a specific name we could look for?

  • Alexis Polti

    Search for “Fresnel lens”

  • Alexis Polti

    Or ask the other grousp (for example Expellariose).

  • Phh

    About obstacle detection, wouldn’t simple bumpers (or contactors, i don’t know the proper name) be more reliable and easy, while enough ?

  • Alexis Polti

    With or without odometry ?

  • Loki

    There is obstacle detection (at a distance) and Collision detection.
    For the 1st one, as you said you can use Ir sensors or Us. The main problem is that these kind of sensor can be very directive so you may need to put several of them on the different sides of the module.
    Be careful about interferences too, especially for US, if all sensors emits a ping at the same time you will receive false positive.

    For collision detection mechanical bumpers are great and simple. There are also IMUs that trigger events on collision.

  • BigFatFlo

    Well we’re going to go with the collision detection, it will be way easier to implement, and more fun to see a robot bump into the obstacles before going around them!

    Thanks for the advice guys!

  • BigFatFlo

    Just FYI, detection bumpers are actually called microrupteurs (in french)! 🙂