PDA

View Full Version : [Question(s)] Which Sonar and why?



Adrenalynn
07-21-2008, 10:21 PM
Time to add some additional sensors, so:

MaxSonar, Devantech, Parallax - which and why?

TIA!

robot maker
07-21-2008, 11:21 PM
i have tried srf-04,srf-02 parallax ping and nothing comes close to lv-maxsonar-z1 proformance,speed and current.only thing they need is I2C type,
beam width it very good,example for current take srf-04 one of the most popular sonars current is 30 to 50 ma, on lv-maxsonar-ez1 is 2 ma plus serial ,analog,and pwm outputs ,and you can use as the same as a srf-04 v+,gnd,ping,echo
here is info on beam angle plots of different sonars comparing to lv-maxsonar-ez1
http://www.maxbotix.com/Performance_Data.html,i bought 30 about a month ago at $20 each

Adrenalynn
07-21-2008, 11:33 PM
The Maxbotics was the direction I was leaning. Specs on the SRF10 are somewhat tempting.

robot maker
07-22-2008, 12:47 AM
i also seem to like srf10 because of proformance and cdr cell they have,but working on a very good light detection circuit
but for a robot nobody beats 2 ma current of the maxsonars,but for my sonar ring using srf-02 mostly its easy to scan 16 in 12 inch ring on I2C BUS, junun.org has the best prices and I2C TO USB adapter.i think the srf10 is $70 each and current near 15 ma,batteries are the most important for a long running robot,and its good to keep the current as low as you can for sensors ,motors and electronics,oops looks like from the proformance data srf10 is not so great compare to maxsonars type


The Maxbotics was the direction I was leaning. Specs on the SRF10 are somewhat tempting.

Adrenalynn
07-22-2008, 12:49 AM
I wouldn't trust Maxbotics published data on their competitors... Has to be a truly independant source before it means anything...

Thanks for the link - but I wouldn't buy any place other than Trossen. Thank you though!

robot maker
07-22-2008, 01:53 AM
i sometime buy at trossens like phidgets boards and some of the sensors,but i check the internet for the lowest prices i can get and buy in bulk,unless i only need 1 or 2 of them for testing or like i2c to usb adapter,for maxsonars i bought from them from maxsonar for about $600 for 30 of them,trossen has 30 for about $900
since i have many robots i will be building,i look for the best prices
also good way to get great prices like the maxsonar that i did to find others to buy some total was $2000 for 100,but they have them for $250 for 10 still much cheaper then any other sites
acroname seems to have the highest prices on most of thier stuff


I wouldn't trust Maxbotics published data on their competitors... Has to be a truly independant source before it means anything...

Thanks for the link - but I wouldn't buy any place other than Trossen. Thank you though!

Adrenalynn
07-22-2008, 02:21 AM
I understand. As far as I'm concerned there's more to price than the published retail price. Service, support, response time, quality of people and company in general. I'm willing to pay a few dollars for that.

If you're buying in volume it's always worth dropping a line to someone like Trossen to see what they can do in volume.

Thanks, though!

robot maker
07-22-2008, 01:33 PM
$150 to $300 is not a few dollars
best it came fast,shipping was cheaper,and when you get it from the factory it always better,only you need to buy alot
will try your idea next time,but since trossen has to buy from the factory,i might not get a better deal
wednesday getting my sensor boards i design,cant wait ,ordered 200 since lot of my friends wanted some for thier robots


I understand. As far as I'm concerned there's more to price than the published retail price. Service, support, response time, quality of people and company in general. I'm willing to pay a few dollars for that.

If you're buying in volume it's always worth dropping a line to someone like Trossen to see what they can do in volume.

Thanks, though!

jes1510
08-08-2008, 10:04 AM
I have used the parallax Ping))) and the maxbotics sensors. Between the two I prefer the maxbotics. It's smaller and since it has an A/D output there isn't much processor overhead needed to play with it. The Ping))) only has a PWM output which forced me to wait and read the full pulse into the processor, during which time I couldn't do anything else.

The Maxbotics sensor also has a PWM output, A/D, and serial. It's a pretty cool device and is cheaper than the Ping))). The Ping))) seemed to have better response up close (around and inch or so) though. The Maxbotics sensor goes wonky if you're sensing closer than 6".

A-Bot
08-08-2008, 11:10 AM
The Ping))) seemed to have better response up close (around and inch or so) though. The Maxbotics sensor goes wonky if you're sensing closer than 6".

This is why I use the Ping. It gives really accurate and consistent readings, and it detects very narrow objects. I haven't had to try a bunch of different range finders because the Ping works so darn well and is easy to use.

Of course I2C is a no-brainer if you need a bunch and I/O ports are limited...

Adrenalynn
08-08-2008, 11:54 AM
Thanks to both of you! I had already ended-up with the Maxbotics.

The 6" limit is no big deal - just move it six inches back on the 'bot. Voila. :)

robot maker
08-08-2008, 04:50 PM
will be easy just to do a offset in software then move 6 inches back,most robots dont too much the room


Thanks to both of you! I had already ended-up with the Maxbotics.

The 6" limit is no big deal - just move it six inches back on the 'bot. Voila. :)

ScuD
08-08-2008, 04:56 PM
As a student - and thus, being poor- it was even more difficult to obtain bot parts back here, but I always liked the idea of the sonar modules.
Then project day came up at school, and everyone built a simple intercom. Always wanting to be different, I built my own "sonar ranger".

The hardware design was actually quite simple, but it was hell to rule out false echos due to reverberation of the transmitter.

It even had a "built-in servo driver" so it would scan about 120 and send out a serial stream of distance vs angle.

After some tweaking , I got the thing to work quite accurate, but I didn't have any time left to build a GUI to give a sort of radar display. Maybe someday.. the board is still back in the shed in a huge tupperware bin.

Hrmm, I just realized I have nothing usefull to add to this thread.

Please regard the above as off-topic..

Adrenalynn
08-08-2008, 05:06 PM
will be easy just to do a offset in software then move 6 inches back,most robots dont too much the room

Nope! Because the sensor gives you erroneous data if you're under the six inches. And frequently that data is unpredictable/unrecognizable.

Also, that few inches can be *really* important.

Most advisable way to accomplish the task is to just physically offset the sensor.

robot maker
08-08-2008, 07:50 PM
in my design ,i have not seen the problem ,works perfect