One-Buck Ultrasonic Sensor

ercoerco Posts: 18,185
10/15 Update: 88 cents. That's just crazy. http://www.ebay.com/itm/New-Arduino-Ultrasonic-Module-HC-SR04-Distance-Sensor-Measuring-Transducer-/181849383810

08/14 UPDATE: Renaming the thread One-Buck Ultrasonic Sensor due to Price Drop: http://www.ebay.com/itm/New-Arduino-Ultrasonic-Module-HC-SR04-Distance-Sensor-Measuring-Transducer-HE-/400756229697

End Update


11/26/12 UPDATE: After a year, I finally changed the thread title from Four-Buck to Two-Buck: http://www.ebay.com/itm/New-Arduino-Ultrasonic-Module-HC-SR04-Distance-Sensor-Measuring-Transducer-Hot-/271040857767?pt=LH_DefaultDomain_0&hash=item3f1b4b46a7

END UPDATE


http://www.ebay.com/itm/270810920267

I lied. $3.95 w/free shipping. Prices on these sensors have been plummeting recently and this is a new low.

I received several of these today, which I paid $4.50 for on October 29. They are pictured and described as SRF-04, which I have used before. 4 pin units. Not PING quality, but very nice. Main bad thing is that they take 2 I/O pins. One trigger, one echo. PING uses just one.

What I received today are newer 4-pin SRF-05 units. Never used these before, and the only info I have found in 10 minutes of searching is at
http://www.robot-electronics.co.uk/htm/srf05tech.htm and
http://www.acroname.com/robotics/info/articles/devantech/srf.html
which implies that these can be used with just one pin, like a PING.

The pinouts on mine are labeled differently than either of these. Mine are labeled:
Vcc---Trig---Echo---OUT---GND so these are some variant or knockoff. I hooked one up to a BS2 tonight using 2-pin mode and it worked flawlessly. I'll request info from the seller about the OUT pin, might take a day to get a reply.

With luck, I'll find out that I can tie the OUT pin to ground and get to one pin mode.
Without any reply or luck, I may tie the OUT pin to ground and release the magic smoke.

So right now, I can't say if they function on one pin, or that the seller will continue to ship 05 units instead of 04's, but they are quite a bargain either way. I just ordered some more. I'm a gamblin' man.
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"When you make a thing, a thing that is new, it is so complicated making it that it is bound to be ugly. But those that make it after you, they don’t have to worry about making it. And they can make it pretty, and so everybody can like it when others make it after you."

- Pablo Picasso
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Comments

  • 146 Comments sorted by Date Added Votes
  • ercoerco Posts: 18,185
    edited November 2011 Vote Up0Vote Down
    "When you make a thing, a thing that is new, it is so complicated making it that it is bound to be ugly. But those that make it after you, they don’t have to worry about making it. And they can make it pretty, and so everybody can like it when others make it after you."

    - Pablo Picasso
  • Martin_HMartin_H Posts: 3,984
    edited November 2011 Vote Up0Vote Down
    Once eBay figures out you are interested in certain types of merchandise they hawk similar auctions on their home page. So I've been seeing those sensors and wondering if they worked because the price seems ridiculously low. So thanks for the product report.
  • Luis DigitalLuis Digital Posts: 352
    edited November 2011 Vote Up0Vote Down
    When I visited eBay page appeared this message: "You bought this item" lol

    Was dispatched on day 8, and I'm still waiting. I've never used an ultrasonic sensor, and I want to experiment with security systems, does not seem enough PIR sensor.

    Thank you.
  • RobotWorkshopRobotWorkshop Posts: 2,300
    edited November 2011 Vote Up0Vote Down
    The open source LEAF project uses the SRF04 sonars modules as the standard means of measuring distance around the robot. The SRF04 seems to have the same signals as those cheap $4 HC-SR04 sonar modules on ebay. The pinout is slightly different but it is easy to account for that. I've heard from one of those users that they provide about the same results as the SRF04 modules in some initial testing. The only downside was that one of the modules was DOA.

    Now if they start shipping a different version like the SRF05 and it doesn't provide the same results then it is going to upset some people that expect the HC-SR04 modules.

    Robert
  • GordonMcCombGordonMcComb Posts: 3,034
    edited November 2011 Vote Up0Vote Down
    The open source LEAF project uses the SRF04 sonars modules as the standard means of measuring distance around the robot.The only downside was that one of the modules was DOA.

    Just to put a fine point on it:lol:, the eBay sellers are providing Chinese knockoff boards, not the Devantech SRF-04s and SRF-05s shipped from the UK. The Devantech SRF-05s have similar specs as the 04s, but can use 1- or 2-pin trigger and echo.

    Alex's control board for the Leaf allows for all kinds of variations, so even if someone uses (say) a single-transducer like those from Maxbotics it shouldn't really impact things.

    -- Gordon
  • ercoerco Posts: 18,185
    edited November 2011 Vote Up0Vote Down
    These SRF05's function perfectly as replacements for the SRF-04 from my initial tests. Last night I tried to get it into one-pin mode (per that first link) by connecting the OUT pin to ground through a 1K resistor (better safe than sorry), but that didn't work. Waiting for a reply from two sellers for more info on the mysterious OUT pin. I haven't found any online documentation yet on this particular SRF05 module.
    "When you make a thing, a thing that is new, it is so complicated making it that it is bound to be ugly. But those that make it after you, they don’t have to worry about making it. And they can make it pretty, and so everybody can like it when others make it after you."

    - Pablo Picasso
  • GordonMcCombGordonMcComb Posts: 3,034
    edited November 2011 Vote Up0Vote Down
    A 1k resistor may be a bit high. Assuming "Out" is the Mode pin, it's going to be pulled high through a pull-up. If you could identify the value of that pullup it would help in knowing whether you can drive the pin low through a resistor.

    -- Gordon
  • ercoerco Posts: 18,185
    edited November 2011 Vote Up0Vote Down
    I'll drop the resistance lower as I gain courage... :)

    I was also thinking that the OUT pin could be a digital output, triggering at some preset distance. I have seen 4-pin lookalike modules from Sure electronics that only had a digital output like that. I need specs and or more time to play.
    "When you make a thing, a thing that is new, it is so complicated making it that it is bound to be ugly. But those that make it after you, they don’t have to worry about making it. And they can make it pretty, and so everybody can like it when others make it after you."

    - Pablo Picasso
  • RobotWorkshopRobotWorkshop Posts: 2,300
    edited November 2011 Vote Up0Vote Down
    Just to put a fine point on it:lol:, the eBay sellers are providing Chinese knockoff boards, not the Devantech SRF-04s and SRF-05s shipped from the UK. The Devantech SRF-05s have similar specs as the 04s, but can use 1- or 2-pin trigger and echo.

    Alex's control board for the Leaf allows for all kinds of variations, so even if someone uses (say) a single-transducer like those from Maxbotics it shouldn't really impact things.

    -- Gordon

    Just to clarify things it was one of the cheap $4 knock off versions that was DOA. I haven't heard anything bad about the real SRF04 modules. You get what you pay for. The cheaper ones may work ok but you may get a substitution you weren't expecting and perhaps there may be a dud mixed in.

    Robert
  • GordonMcCombGordonMcComb Posts: 3,034
    edited November 2011 Vote Up0Vote Down
    Robert, I figured you meant the imported ones (though to us Americans boards from the UK are also "imported"!). For passers-by I just wanted to make note of the fact these are knockoffs, and aren't from Devantech, despite the product names.

    Besides, both Gerry in the UK and Steve (at Acroname, Gerry's US distributor) would replace the DOA in a heartbeat.

    -- Gordon
  • ercoerco Posts: 18,185
    edited November 2011 Vote Up0Vote Down
    First useful info I've found on that OUT pin, this implies that it is likely what I suspected, a digital output for a proximity warning. There's a dangerous-looking link for the datasheet that tries to download an exe. file. I requested info straight from the seller.

    http://www.ebay.com/itm/Ultrasonic-Wave-Distance-measure-Module-Ranging-Sensor-/190548468478?pt=LH_DefaultDomain_0&hash=item2c5d92e2fe
    "When you make a thing, a thing that is new, it is so complicated making it that it is bound to be ugly. But those that make it after you, they don’t have to worry about making it. And they can make it pretty, and so everybody can like it when others make it after you."

    - Pablo Picasso
  • tonyp12tonyp12 Posts: 1,821
    edited November 2011 Vote Up0Vote Down
    You always have to be carful with free file storage sites.
    The ads are made to look like the real down load link.

    Here is the real file.
    Ultrasonic.zip
  • ercoerco Posts: 18,185
    edited November 2011 Vote Up0Vote Down
    That readme file implies that the OUT pin goes low any time an object is detected. I'll check that out and report back. Thanks tonyp12!
    "When you make a thing, a thing that is new, it is so complicated making it that it is bound to be ugly. But those that make it after you, they don’t have to worry about making it. And they can make it pretty, and so everybody can like it when others make it after you."

    - Pablo Picasso
  • ercoerco Posts: 18,185
    edited November 2011 Vote Up0Vote Down
    Only one helpful reply from several Chinese sellers of this 5-pin item, and of the mysterious "OUT" pin, they only say "don't connect" ! :)

    http://www.emartee.com/Attachment.php?name=41365.pdf
    "When you make a thing, a thing that is new, it is so complicated making it that it is bound to be ugly. But those that make it after you, they don’t have to worry about making it. And they can make it pretty, and so everybody can like it when others make it after you."

    - Pablo Picasso
  • Martin_HMartin_H Posts: 3,984
    edited November 2011 Vote Up0Vote Down
    I have a project in the planning stages that requires a whole bunch of distance sensors. So I just purchased four of these, I figure that with shipping delays they should arrive right around the time all my in-flight projects complete.
  • ercoerco Posts: 18,185
    edited November 2011 Vote Up0Vote Down
    Martin_H wrote: »
    I just purchased four of these, I figure that with shipping delays they should arrive right around the time all my in-flight projects complete.

    Dat's my dawg!

    I gotta figure a way to get a dime per sale off all my Ebay recommendations. You tentatively owe me 40 cents. I'm keepin' track, Pal! ;)
    "When you make a thing, a thing that is new, it is so complicated making it that it is bound to be ugly. But those that make it after you, they don’t have to worry about making it. And they can make it pretty, and so everybody can like it when others make it after you."

    - Pablo Picasso
  • Luis DigitalLuis Digital Posts: 352
    edited November 2011 Vote Up0Vote Down
    Hello again :)

    My sensor is HY-SRF05 (pictured say HC-SR04), and tested it with the object of Parallax "ping.spin", with some modifications because the sensor uses two pins.

    Measured with precision, but after 102 inches (2.5908 meters), usually lose the range.

    Is it normal?

    On the eBay page says: Distance range: 2cm-450cm (4.5 meters).

    Thank you.
  • ercoerco Posts: 18,185
    edited November 2011 Vote Up0Vote Down
    Interesting, I tested one of mine and it maxed out at ~120 inches, so maybe the long-range accuracy of these cheaper sensors is the limiter. When I get a chance to test some other units, I'll report back if I get different results.
    "When you make a thing, a thing that is new, it is so complicated making it that it is bound to be ugly. But those that make it after you, they don’t have to worry about making it. And they can make it pretty, and so everybody can like it when others make it after you."

    - Pablo Picasso
  • Luis DigitalLuis Digital Posts: 352
    edited November 2011 Vote Up0Vote Down
    erco,

    It also depends on the surface, maybe if we use a larger barrier object sensor can see.

    I am using an object 14 inches diagonal, as a barrier.

    Parallax sensor operates in the range that promise?
  • RobotWorkshopRobotWorkshop Posts: 2,300
    edited November 2011 Vote Up0Vote Down
    I did receive some of these Sonar modules yesterday to test. When I opened the package I was one module short. The seller said they would get another one in the mail to take care of that.

    The quality looks ok on them but there are a couple important differences worth mentioning. First, the spacing of the transducers is wider than the Standard SRF-04 modules. That may cause problems for those that use a bracket or mounting that needs the sensors in the normal location. Second the mounting holes are very tiny. I'm used to the SRF-04 and the Parallax PING that can use a #4 screw for mounting. For the knock off modules that isn't going to work. You'll need a smaller #2 screw, double faced tape, or glue.

    I think for my main projects I will keep on using both the Devantech modules and the Parallax PING sensors. For odd projects these cheap ones will probably work just fine and I'll be able to find a use for them somewhere.

    Robert
  • ercoerco Posts: 18,185
    edited November 2011 Vote Up0Vote Down
    Noted. I haven't been able to get any function of the extra alarm pin yet, so these SRF05 modules are functionally the same as 04s. Still functions great and quite a good value for the "let's have 16 sensors all around our circular robot chassis" crowd. :)
    "When you make a thing, a thing that is new, it is so complicated making it that it is bound to be ugly. But those that make it after you, they don’t have to worry about making it. And they can make it pretty, and so everybody can like it when others make it after you."

    - Pablo Picasso
  • ajwardajward Posts: 1,073
    edited November 2011 Vote Up0Vote Down
    Just received three today (05's). Gonna try to get them working later, if I can shake off the oogies! :-|

    @RobotWorkshop It =kinda= looks like there might be room to drill out the mounting holes just a bit. I'll try one tomorrow.

    @
    Founder of the "Society for Aimless Tinkering and World Conquest"
  • Martin_HMartin_H Posts: 3,984
    edited November 2011 Vote Up0Vote Down
    I am jealous as mine haven't come yet. Maybe my Parallax order will come soon.
  • ercoerco Posts: 18,185
    edited November 2011 Vote Up0Vote Down
    Man, if everyone here ordered some, I gotta get my 2% kickback...

    FAIL.
    "When you make a thing, a thing that is new, it is so complicated making it that it is bound to be ugly. But those that make it after you, they don’t have to worry about making it. And they can make it pretty, and so everybody can like it when others make it after you."

    - Pablo Picasso
  • GordonMcCombGordonMcComb Posts: 3,034
    edited November 2011 Vote Up0Vote Down
    What are the kind of ultrasonic sensors they use in rear bumper parking aids? Those look fairly rugged. They're also (at least the ones I'm behind in the McDonald's drive-thru) single transducer.

    -- Gordon
  • RobotWorkshopRobotWorkshop Posts: 2,300
    edited November 2011 Vote Up0Vote Down
    erco wrote: »
    Man, if everyone here ordered some, I gotta get my 2% kickback...

    Sorry Erco, I had come across these on my own surfing ebay before reading your post. No 2% on this one.....
  • ercoerco Posts: 18,185
    edited November 2011 Vote Up0Vote Down
    @Gordon: Hurry, half off now! Just $104 each at http://www.1aauto.com/1A/Electrical/Cadillac/Escalade/1AZMX00002/327437

    Heck, mine are exactly $100 less. Plus free shipping! :)
    "When you make a thing, a thing that is new, it is so complicated making it that it is bound to be ugly. But those that make it after you, they don’t have to worry about making it. And they can make it pretty, and so everybody can like it when others make it after you."

    - Pablo Picasso
  • Martin_HMartin_H Posts: 3,984
    edited December 2011 Vote Up0Vote Down
    My four sensors arrived over the weekend and I finally got the time to test them today. They seem to work fine, but there is that mysterious fifth pin that doesn't seem to do anything.

    Anyway all the parts for my next build have arrived, so it's time to get cracking.
  • photomankcphotomankc Posts: 929
    edited December 2011 Vote Up0Vote Down
    Got my three in the mail yesterday. Going to be a bit before I ever get around to testing them out.
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