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Which sensor to use? — Parallax Forums

Which sensor to use?

Mack6225Mack6225 Posts: 3
edited 2011-08-10 05:17 in Accessories
My project is this; I live in an electric wheelchair, September will be 11 years. Everyone I’ve ever met says the same thing, that you will run into walls and knock the corners off door jams, ding the frig., etc. etc. Unavoidable. So, I want to install distance sensors around the perimeter of my chair which will warn me when I am 3 inches away and interrupt the control signal to my wheels (stop the chair) at 2 inches away from an object. My thoughts are BS2 since I already made friends with her and have a BOE. I am thinking of using:

GP2D120 Sharp analog distance sensor probably 7 or 8 www.pololu.com/catalog/product/1136
8-Channel 12-Bit A/D Converter with SPI Serial Interface MCP3208-BI/P Parallax # 604-00062
Small Piezo and large LED.

Any comments, suggestions, criticism, etc. (Point the old cripple in the right direction advice) would be greatly appreciated. Thanks in advance.
I use a combination of sensors. I couldn't cut the power without voiding the warranty. So I used a separate power supply and warn my self with a vibration motor clipped to my waist. Thanks to all who responded.

Comments

  • FranklinFranklin Posts: 4,747
    edited 2011-07-19 21:20
    Sounds like a good project and should be a rewarding project.. This http://www.pololu.com/catalog/product/1135 might also be an option and would be easy to connect to the stamp.
  • piguy101piguy101 Posts: 248
    edited 2011-07-20 13:17
    Probably the easiest but most expensive thing to do is to go with the Parallax PING))). 8 PINGS should be plenty to cover the perimeter.
  • Mack6225Mack6225 Posts: 3
    edited 2011-07-20 13:29
    Thank you for your input. I understand by your post that you are suggesting I go this route for a cost savings? That's great and I looked at the carrier board that Pololu has for this product/1135. I am looking for a plug and play type solution. But the carrier board would save a wad and not to much soldering and no additional components. This great advice thanks.
  • Mack6225Mack6225 Posts: 3
    edited 2011-07-20 13:31
    There is no room for a component as large as a Ping. Especially as many as I would need. Thanks for you input though.
  • PliersPliers Posts: 280
    edited 2011-08-09 15:23
    I think this is a great project.

    My initial thoughts are to use a capacitance sensor.
  • graffixgraffix Posts: 389
    edited 2011-08-09 15:50
    Then use ir leds?
  • kwinnkwinn Posts: 8,697
    edited 2011-08-09 22:19
    A reflective led reflective sensor might be the way to go. Small, inexpensive, and could be driven at a specific frequency to minimize interference.
  • PliersPliers Posts: 280
    edited 2011-08-10 05:17
    The idea behind the capacitor sensor is that the wheel chair is the sensor.
    The metal frame of the wheel chair would be the detector. As it moves along a path near obstacles. there would be a varying electric field surrounding the wheel chair.

    I would use an RF frequency so that the surrounding would look like a ground path for the sensor.
    The system would need four RF antennas: front , back, left and right.
    The feed back for the operator would be an audio signal indicating left, right, back or front obstacle. The louder the signal the closer to the object.
    The speaker could be mounted in the back of the chair near the operators head.
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