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PING/Sharp IR Sensors on 3.7V — Parallax Forums

PING/Sharp IR Sensors on 3.7V

ercoerco Posts: 20,259
edited 2012-06-18 08:53 in General Discussion
Anybody try running these sensors at lower than 5V?

No good?

Comments

  • GordonMcCombGordonMcComb Posts: 3,366
    edited 2012-06-15 09:46
    Pings won't work under about 4.7 volts.

    Hard to know about the Sharp IR sensors as there have been many, made over quite a number of years. The analog sensors may be more forgiving than the digital ones, but even so, the output accuracy could be one of those knowable unknowns.

    -- Gordon
  • ercoerco Posts: 20,259
    edited 2012-06-15 09:50
    Pings won't work under about 4.7 volts.
    -- Gordon

    Thanks Big Guy! Good to get the straight scoop from the master.

    BTW, if Charlie Sheen and I find a single off-spec Ping which operates at 4.6 volts, are we "Winning" with Tiger Blood?
  • GordonMcCombGordonMcComb Posts: 3,366
    edited 2012-06-15 10:12
    erco wrote: »
    BTW, if Charlie Sheen and I find a single off-spec Ping which operates at 4.6 volts, are we "Winning" with Tiger Blood?

    Stranger things have happened. For a Radio Shack project I did I tried to use their "universal" power adapter. It has a 4.5V and 6V tap, but no 5V tap. It wouldn't work at 4.5V (actual unloaded voltage about 4.6V -- ergo "under 4.7V"), and 6V is a little high for the Ping. I ended up using their 6V adapter with a diode.

    Anyway, here's Charlie...
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2012-06-18 07:16
    Actually, a Ping has an SX28 chip on board that is likely programmed with a brown out at 4.7V. But this could easily be revised to tolerate a lower voltage in Parallax wanted to provide more voltage range.
  • ercoerco Posts: 20,259
    edited 2012-06-18 08:27
    Actually, a Ping has an SX28 chip on board that is likely programmed with a brown out at 4.7V. But this could easily be revised to tolerate a lower voltage in Parallax wanted to provide more voltage range.

    With 3.3V processors and 3.7V Li-Ion batteries all the rage now, you'd think someone would be working on 3V sensors, huh?

    I've seen at least one complaint about voltage translators and such. :)
  • GordonMcCombGordonMcComb Posts: 3,366
    edited 2012-06-18 08:51
    Drive voltage against an ultrasonic transducer is usually an important thing. With no other change, given a lower voltage the transducer wouldn't be hitting as hard, and likely would not have the same range. I imagine altering the Ping to work at 3.3V would entail a number of critical engineering changes. Were this not the case I'm sure by now we would have seen a Ping Rev x with a broader voltage latitude.

    That's just a guess, of course. After all, all I have is just old tomcat blood.

    -- Gordon
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2012-06-18 08:53
    Gordon has a very good point. In this case, the physics involved in the ultrasonics wins out. You simple get more range.

    But it is possible for short range devices.
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