Mystery Sonar: SonaSwitch Mini-S

[DigiTan]

I recently got a EDP SonaSwitch sonar and started testing it yesterday.

The trouble is, all the web documentation on it is fiendishly vague, and it barely gives me enough instructions to keep from damaging it. To give you an idea, the official data sheet is only 1 page long. I'm writing some µcontroller code to test it, but it is all trial-and-error at this point. I was hoping someone here might have some advice on it, or at least a link to a more detailed guides or a schematic...anything.

Also, when I power up the sensor I can hear a rapid clicking that is obviously out of the ultrasonic range. Is this typical for ultrasonic sensors, or is it fried? It's described as an "electrostatic transducer" with a repitition rate of 10Hz (astable). The clicking I'm hearing seems much closer to 3 or 4 Hz though.

 

[zachtheterrible]

hey digitan. I can hear a clicking whenever I go by ultrasonic bird repellers or door openers etc. Its always faster than 3-4hz though

 

[Russlk]

From my reading of the data sheet (if you can call it that), this is a transmitter and receiver. All you have to do is apply 5 volts, adjust the max and min range, and if the target is within that window, there is an output from OC1 or OC2. What kind of response are you getting?

 

[DigiTan]

You're right Russlk, it's no data sheet, it's more like a brochure...if even that much. :roll:

Anyway, I used a logic pen to watch the clock and two output pins while it was pointed at a wall. The clock was low with short, high pulses happening as the sonar clicked away at ~3Hz. I used 10MOhm pull-down resistors on the outputs and got an almost identical signal, except the rising pulses were much shorter. So already, the sensor isn't matching the "data sheet." Pointing it at empty space had no change.

I programmed an AVR controller, to record the sensor state on each clock pulse and display a red/green LED for misses/hits. The controller always reads "miss" matter were it's pointed, so these output pulses clearly don't match the clock.

Geez, if there's one thing I hate more than a broken device, it's a working one that's poorly documented. :x Lame! Lame! Lame!!

 

[Pyroandrew]

have you tried phoning them? If you give the company a call and ask for a full datasheet, you will probably get quite far. If however, they turn out to be a re-seller, you will need to ask them for the company that manufactures the devices. Good luck

 

[DigiTan]

Yes, I am in the process of this now. I'll email them if they've got data sheets or app notes. There are a lot of robot and 'smart wheelchair' programs involving those sensors too, so I'm trying to reach the developers.

 

[bbiandov]

Yes, I am in the process of this now. I'll email them if they've got data sheets or app notes. There are a lot of robot and 'smart wheelchair' programs involving those sensors too, so I'm trying to reach the developers.

Have you figured out what the clock output does? Is it just a simple square wave or does its width represent distance to the target?

I saw some posts that alledge that output is actually TOF (time of flight) which would be super cool. However when I measure it on my sensros its a 5Hz clock with strange duty cycle - 198ms high and 2ms low... and it does NOT change depending on distance to target

 

[ericgibbs]

Have you figured out what the clock output does? Is it just a simple square wave or does its width represent distance to the target?

I saw some posts that alledge that output is actually TOF (time of flight) which would be super cool. However when I measure it on my sensros its a 5Hz clock with strange duty cycle - 198ms high and 2ms low... and it does NOT change depending on distance to target

hi,

If he hasnt figured it out yet, he never will.. the thread is 3 years old.

 

[KMoffett]

You're right Russlk, it's no data sheet, it's more like a brochure...if even that much. :roll:

Anyway, I used a logic pen to watch the clock and two output pins while it was pointed at a wall. The clock was low with short, high pulses happening as the sonar clicked away at ~3Hz. I used 10MOhm pull-down resistors on the outputs and got an almost identical signal, except the rising pulses were much shorter. So already, the sensor isn't matching the "data sheet." Pointing it at empty space had no change.

I programmed an AVR controller, to record the sensor state on each clock pulse and display a red/green LED for misses/hits. The controller always reads "miss" matter were it's pointed, so these output pulses clearly don't match the clock.

Geez, if there's one thing I hate more than a broken device, it's a working one that's poorly documented. :x Lame! Lame! Lame!!

Is this the spec sheet you all are looking at?: **broken link removed**

Which model do you have the "A" or the "S". The OC outputs on the "S" are open collector NPNs and would require a "pullup" resistor (10K?) in order to get an output voltage. The OC outputs do not function on the "A".

Looks like the clock pulse signals the start of the measurement...good for an interupt. And the "Two (2) adjustable NPN open collector outputs; transistors are continuously energized during detection period." would make the pulse width = time-of-flight. Don't know why two though. ???

Worth a call though.

Ken



Oops... I should remember to look at the date...#!*?&

 

[Willbe]

I can hear a rapid clicking that is obviously out of the ultrasonic range

Just my two cents, but a "click" contains all freqs.
https://en.wikipedia.org/wiki/Impulse_response

 

[bbiandov]

Its "S"

Yes the OC outputs are nice but I want distance data. So I figured the clock is really a PWM of the TOF - I have no idea why they labeled it as clock. The closest object reading is at 2.1ms positive pulse duration so I figured that is the internal delay to detect the echo and trigger the PWM circuitry to lower the edge so then (x-2.1) * speed of sound /2 gives distance with scary precision. My tape measure tests surprised me - I did not expect this little toy to be so accurate. I am sure at altitude or funny temperature environment its accuracy will have to be adjusted but here on earth it works guuuuud

I wish I got more of those back in the day when MPJA had them for $9 each

~B

 

[bbiandov]

Yes Mini-S DO provide range information

Yes Mini-S DO provide range information. The range is between 0-10 feet or 18.6ms to 3ms

I found those at mpja.com for $8 each - what a steal. I got several and then I went back to get more but they ran out of stock by then

When run throught the speed of sound formula/2 the actual tape meassure tests are extremely accurate. I am sooo happy with those. And yes, if you dont want range PWM data there is a simple OC ttl output - short to GND when object in range and Z otherwise.

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**broken link removed**
**broken link removed**

Take a look at the manual**broken link removed**

 

[glennmiller@surewest.net]

Many Versions of the SensComp Mini Sensor...

If you purchased the sensor from a reseller, you may have a OEM sensor similar to the Mini A and Mini S models. The sensor is actually two components; The ultrasonic transducer is a Polaroid 600 q.v. US Patient 4872148. The other, connected to it is the sonic ranging board. For a close to but not exact data-sheet see the Polaroid 6500 sonic ranging board spec. SensComp purchased EDP and Polaroid was an OEM partner. You'll get your best information from the US Patient web sites and Polaroid 9000, Polaroid 600, and Polaroid 6500 searches. The 6500 data-sheet gave me what I needed to make use of the sensors I picked up from HSC, now HFE here in Sacramento, CA. Incidentally, I got mine, 2 for a buck. Have fun, enjoy the chirp.

Redbanks

"Good artists copy. Great artists, steal..." Picasso

 

[bbiandov]

HSC still exists in Santa Clara.

HSC Electronic Supply - Silicon Valley's Electronic Marketplace

Its a cool place but web site doesnt show the entire inventory

Is HFE in Sacramento a walk-in kinda shop?

 

[glennmiller@surewest.net]

HSC Sacramento Now HFE...

It's similar to Santa Clara's - walk in, brouse the aisles, remember the prices or use the golf pencil, paper and tote method. It's only about 60% the size. It's located very near a community college that had "the" electronics tech program back when there were components that needed a technician to troubleshoot. Business fell off and HSC decided to close the store down. The employees and customer base bought the inventory and lease and it proudly continues operating today. The name changed to HFE which is exactly what it sounds like. They joked the name only took a couple of minutes to come up with. Everyone involved was good with it and besides, when someone calls, if you kind'a mumble it, to the unaware caller, it sounds like they've reached HSC.