Range Finders
2008-04-01 02:16
Ok so I just posted a question about wheels and now I'm on to
my next component in my first robot..range finders.
I see the SRF05 is popular which I can purchase here..http://www.hobbyengineering.com/H2262.html
They also seem to have a bunch of others like SRF04 and SRF08, anyone care to break
down the difference for me?
Next I see this sensor which also looks nice using 3 pins..the ping sensor..http://www.hobbyengineering.com/H2951.html
on a PICAXE 28x1 which will be my best bet?
also I figure I'll get this handy little gadget.....http://www.hobbyengineering.com/H2952.html.
Thanks a lot, to all of you. I'm a senior in high school
headed off to college for robotic engineering so I think this
site is a nice home for me.
PS I'm in the states :)
To put it short; The
To put it short; The different range-finders have different specs in speed, versatility, range, reliability, price etc..
I recomend the SRF05 for Picaxe, as it is so well documented, and it is really good!
For the ping, there are guys in here who is using it:
http://letsmakerobots.com/search/node/ping
i know Chris the Carpenter might have some experience regarding Picaxe and Ping
/ Frits
DO NOT buy the 3 pin!
Hey Bryan,
I don't know much about the different FR0's but I can say the Ping 3-pin will not work with a picaxe. The 3 pin is for a Stamp board and one pin is used for both input signal and output as well. The picaxe uses 2 different pins for I and O -thus 4 wires. Other than that the FR05 seems to be the standard everywhere.
www.rocketbrandcustom.com baby!!
ERHM - The Ping SHOULD work
ERHM - The Ping SHOULD work with the Picaxe, I am PRETTY sure!
Pretty - I did post you some on this somewhere, Chris, no?
BUT.. I agree - do not do the 3-pin - alone for the fact that it is not as good a solution; Harder to code, not as fast result, only a solution if you have less ins / outs and want to spare one.
/ Frits
The Ping thing...
Hey folks,
In terms of the 3 pin and 4 pin... the problem I ran into is that the 3-pin uses a single pin for input and output. The stamp controller, it seems, has pin that allows for rapid toggle between I and O. The "ping" unit is "stamp" brand after all. When I say it didn't work with a picaxe, is not to say it won't but from what I am seeing you would have to use 2 channels with diodes so the output pulse would not get sent directly to the input pin of the picaxe. I guess the 08m would do it on one channel if it could toggle from I/O fast enough. I dunno... for me, I would rather just get the propper accessory and spend time coding instead of having to MacGyver for a night to get it to work. In conclusion, I am wicked new at all this, just lettin' ya'll know what I think I know.
www.rocketbrandcustom.com baby!!
Nononoo!! There are plenty
Nononoo!!
There are plenty of pins on thePicaxes that can be used for both out and in. With the smaller Picaxes this is very common to use because you have so few pins - which is also why the SRF05 when shipped from picaxe comes with instructions on how to use it with only 3 pins.. I think I wrote this to you, no?
Yes, I did :D http://letsmakerobots.com/node/66
Also look at this, written when I was about to make Yellow Drum Machine: http://letsmakerobots.com/node/113
/ Frits
No problem on Arduino either
I've successfully used a PING on an Arduino too. Here was my code for that:
#define SONAR_PIN 9
unsigned long ping()
{
pinMode(SONAR_PIN, OUTPUT); // Switch signalpin to output
digitalWrite(SONAR_PIN, LOW); // Send 0-1-0 pulse to trigger PING
delayMicroseconds(2); // Wait for 2 microseconds
digitalWrite(SONAR_PIN, HIGH); // Send high pulse
delayMicroseconds(5); // Wait for 5 microseconds
digitalWrite(SONAR_PIN, LOW); // Go back to low
pinMode(SONAR_PIN, INPUT); // Switch signalpin to input
digitalWrite(SONAR_PIN, HIGH); // Turn on pullup resistor
unsigned long echo = pulseIn(SONAR_PIN, HIGH); //Listen for echo
unsigned long sonar_value = (echo / 58.138) * .39; //convert to CM then to inches
return sonar_value;
} // unsigned long ping()
I had no problems with response time, I think switching between input and output happens pretty fast.
Hi Bryan4,So, basicly the
Hi Bryan4,
So, basicly the are made for diferente proposes, as u can find here, the SRF04
*: Approximate angle of the sensor cone at 1/2 sensor range (see diagram above).
**: The number of echoes recorded by the sensor. These are the recorded echoes from the most recent reading, and are overwritten with each new ranging.
A: These sensors are smaller than the typical (SRF 04 / 05 / 08) size.
B: Range time can be adjusted down by adjusting the gain.
C: This sensor also includes a photocell on the front for light detection.
About the PICAXE 28x1, i never used it, sory can't help you on this!
Thanks