Shop OBEX P1 Docs P2 Docs Learn Events
Sharp Analog Sensor as Digital Proximity Sensor — Parallax Forums

Sharp Analog Sensor as Digital Proximity Sensor

ercoerco Posts: 20,261
edited 2012-09-21 14:55 in Accessories
Uses Sharp GP2D120 IR distance measuring sensor. Might come in handy for someone without an ADC someday. Shown on "another" processor, but works exactly the same with a Stamp. Triggering range is fixed at ~3.5 inches, based on the output characteristics of the sensor. Notice the Parallax "Inventor's Wand" on my desk? :)

Comments

  • davejamesdavejames Posts: 4,047
    edited 2012-09-18 10:17
    ...love the "make it work" attitude!
  • ercoerco Posts: 20,261
    edited 2012-09-18 11:16
    Sometimes at 3 AM, you have neither the ADC, (processing) time, nor energy to get the analog reading, but you still gotta git 'er done.

    I'm working on a beacon trackin' app which uses this as a crash sensor. You'll see a video soon.
  • davejamesdavejames Posts: 4,047
    edited 2012-09-18 13:20
    ...understood - it's just cool seeing what people will do to "giterdone".

    I love the ingenuity in taking something and squeezing it into an application tangential to its original purpose.
  • Martin_HMartin_H Posts: 4,051
    edited 2012-09-19 08:01
    The TSL1401 line scan sensor returns an analog voltage to indicate pixel brightness, but when Phil uses it with a stamp he uses it like a digital sensor. By controlling the exposure time he can control the gain and thus the threshold when a pixel transitions from 0 to 1. So if your analog sensor has some sort of gain control you could control the distance at which its logic state changes. If it lacks that I imagine using a pot as a voltage divider might do the trick.
  • ercoerco Posts: 20,261
    edited 2012-09-19 10:15
    Yessir, a simple voltage divider could reduce the voltage, thereby reducing the range. But since the range is 3-1/2 inches as-is, it's more likely that people would want to increase the range. A cheap op amp could do that easily.
  • GordonMcCombGordonMcComb Posts: 3,366
    edited 2012-09-21 12:14
    I see you've put your FREE Harbor Freight multimeter to good use.

    -- Gordon
  • ercoerco Posts: 20,261
    edited 2012-09-21 14:55
    Confound you, Gordon! Nothing gets past you! :)

    I'm probably not the only guy here with three or more of those meters. One was free and the others are maybe 3 bucks. They're perfectly adequate for measuring typical plywood voltages.
Sign In or Register to comment.