SF-02 laser range finder
prof_braino
Posts: 4,313
A while back, a thread discussion resulted in the DS00, a surveyor grade laser range finder with a range of about 350 meters. That effort has evolved into the SF-02, a less expensive unit that targets us, the pro-hobbyist enthusiasts.
The SF-02 laser range finder has range of about 40 meters (minimum full sunlight), and does about 12 samples per second. Accuracy should be about 1 cm over the entire range. The package is said to weight 70g.
I might be able to get hold of a few early parts. The specs may be different when the actual parts arrive, but the these should be close.
Is anybody interested in this?
Note: This sensor is not intended to compete with any Parallax offerings, as it is completely different than most anything on the market that I know of. If this post violates any polices or anything, please let me know and I'll remove it if the moderators don't get to it first.
The SF-02 laser range finder has range of about 40 meters (minimum full sunlight), and does about 12 samples per second. Accuracy should be about 1 cm over the entire range. The package is said to weight 70g.
I might be able to get hold of a few early parts. The specs may be different when the actual parts arrive, but the these should be close.
Is anybody interested in this?
Note: This sensor is not intended to compete with any Parallax offerings, as it is completely different than most anything on the market that I know of. If this post violates any polices or anything, please let me know and I'll remove it if the moderators don't get to it first.
Comments
I'm interested in this device.
As a lot things I'm interested in, my willingness to part money for it will depend on the price of the device. Has a price been set yet?
IIRC, the earlier version was reasonably priced. I just didn't have a need to justify the expense.
http://www.parallax.com/product/28044
Iv'e noticed stuff has been changing today.with the website and links.
It's on the beta site, here.
Guess the beta went LIVE!!! It's linked out of this product page.
I was always impressed by laser targeting ever since the original Andromeda Strain way back in ....well, a long time ago....I guess they went a bit beyond "targeting"!
The ds00 direct price was $350 USD, the SF-02 is supposed to be slightly cheaper between $300 and $350 USD. I suppose it has to do with production cost and volume, we should have a solid number shortly, I know cheaper tends to be better.
One factor the may be of interest is the original ds00 weighed in at 210g, while the SF-02 weighs only 70g. I think most of the weight was in the first generation optics, the lenses heavy and the lens mounts were metal. I think the new lenses are a lighter material, and there might be a plastic lens mount. Again, I won't know for sure until I get it in my hands.
I did see Joe's LRF in a couple articles. The range was only about two meters and it did not do so well in direct sunlight. Also I don't recall it doing 12 readings per second. Of course, Joe's was much lower priced, so would be appropriate some applications and not for others.
Whatever became of the "not for sale in the USA" stipulation?
One thing that's cool about Joe Grand's LRF is it uses a camera which can be hacked for other purposes.
Parallax's LRF use triangulation to find distances. I believe the SF-02 measures the time of flight of the laser light (a much harder task IMO).
Time of flight. It was hard to get my hear around this method the first time around. It does a LOT of fast measurements, and build these into a single reading. It can't find the term that got me the wiki page that cleared it up, but here' how I see it:
Its sorta like an optical strobe tuner on a guitar string. The strobe is flashing at the desired frequency, and the string is vibrating at a similar frequency. The difference between the two is seen as a much slower pulse that slows down and eventually stops when the string is tuned to the proper frequency, as flashed by the strobe. This isn't quite the same as what the laser is doing, but helps me get my head around how lots of fast stuff we can't see can be combined into a something we can see and measure. Maybe it is the same except instead of changing the frequency of the string, we are changing the distance to the target. Now my head hurts, I better take a walk.
here it is: http://en.wikipedia.org/wiki/Digital_down_converter
It had to do with FDA approval for the class 1M laser. Since this is a bunch of paper work, expense, and PITA, he opted to hold of on the expense until the "real" production unit was ready. It also allowed him to sell off the first run (DS00) to pay for this one. As I understand it they sold very quickly, which is why he continued with an item to be sold in the US.
I believe the paperwork has all been shuffled, and the laser tested on an official certified class 1M laser testing machine (whatever that might be). So we should be seeing them sometime soon.
Delve deeply into the details of Michelson's 1922-28 apparatus to measure light's time of flight, and that will get your head (and 16-sided mirror) spinning: http://www.otherhand.org/home-page/physics/historical-speed-of-light-measurements-in-southern-california/the-mount-wilson-station-1922-1928
The explanation in the lightware documentation has a picture. It shows lots of little, quick pulses. We can detect they happened, but can't really see the shape of the wave. The device triggers and detect s whole bunch of these, and gradually they are compiled into a larger, slower pattern the reveals the average of the small events. Kind of like doing a pencil rubbing on an old headstone. It does a whole slew of individual events, and reports the composite measurement 12 times a second.
To me its pretty cool, even though I have to think it through each time.
A couple folks started talking about using this hardware with a Doppler algorithm. Lightware say it should be possible, the raw data can accessed programmaticly via the built in microcontroller, and/or sent out for external processing. I don't know how well it will work. Somebody should say its impossible.
70 grams, fits inside a cigarette pack (although the lens diameter is slightly bigger than the pack, so I can't close the top)
Out of the bag, connected to the USB port, the terminal program starts spitting out distance readings, just as the DS00
In outdoors on an overcast, humid afternoon, 43F, the farthest reading I got were 39-40 meters, when aimed at a reflective target (stop sign, lisense plate). Probably have to adjust something to get 60 meters, or maybe it was just too damp?
Distances below 20 meters were very consistent. Out of the box with default setting, 20 meters and below are very repeatable.
The deviation is about 2 cm minimum. When detecting the wall (about 1.39 metes) the reading were 1.38 to 1.40 m. Outside the reading bounced a little bit more, but I was walking and it was raining, I'll have to do a better test later.
Closest it reading was about 6 cm when it displayed 0.00 meters. There is an offset in the firmware that we can adjust for the edge of our robot, but I didn't mess with it yet.
Summary: This thing is awesome and totally rocks!
The SF02 is listed at $250. The shipping cost from South Africa is about $320. So the total cost to the purchaser direct from the manufacturer is $570. Wowsers! EDIT OK this is way wrong how do strikethrough?
The US price should be $350 plus local shipping. The unit is about 75 grams and about as big as a pack of cigarettes.
Anybody have any suggestion as to which US shipping is best for this situation?
I could use any of FedEx, USPS, or UPS, there are offices for each close by.
$350 for 75 grams?! Is it shipped via the Kon-Tiki, or someting?
Do you need a wide angle measure?
Otherwise top notch units like this one are much cheaper:
http://www.amazon.com/Leica-DISTO-Laser-Distance-Measurer/dp/B001AOUQXG/ref=sr_1_1?ie=UTF8&qid=1383570432&sr=8-1&keywords=disto+laser
or not top level:
http://www.amazon.com/Laser-Distance-Meter-Uni-t-Ut391/dp/B008HNW9ZQ
Don't know if you can hack them...
Consider real life range is about half.
Masismo
In regard to the Leica Disto models, I hacked a much earlier model years ago with an SX chip, and it was a real bear. Had to interface to the output of the LCD driver, and the segments zoomed by very fast. I doubt a Propeller would be fast enough.
Cheers,
Peter (pjv)
The SF02 is listed at $250. The total direct shipping cost from South from the manufacturer in Africa is about $320. So the shipping cost itemself is $70
The US SALE price should be $350 plus local shipping. The unit is about 75 grams and about as big as a pack of cigarettes.
We had some discussion on this when the first protoype came out.
Lase Developer says the next cheapest unit comparable to the DS00/SF02 is over $1000
I fiugre if a cheaper unit could be hacked, somebody smart would have done it already.
Remeber, this is not cheap electronics in a pretty expensive platic case that you are going to remove andthrow away, with a crappy stupid proof user interface that you have to work around. This is a the guts, nothing else, waiting to be put directly into your projects, and this is how it was designed from the get go. I made sure ot that when we started.
This unit is $250 of pro-quality laser sensor, and $70 of importing from SA.
It is fast, but not accurate.
For sure hacking a disto must be a nightmare, but the guts are quite nice, and some aspects outperform this unit at 1/3 the cost.
Sf02 looks tailored for almost real time height from ground in a UAV. A handeld disto is for a very different use. Hence speed and accuracy.
I spent the evening upgrading my OLPC XO-1 so I can do proper outdoor testing. I plan to mount a visible light green laser in parallel for aiming. I'm getting the idea the SF02 is more accurate than in the documentation. It turns out the angle of the target surface is a big factor. When the target is even slightly off from orthogonal, the reading vary because the distances can change by several centimeters. It gets reading from the nearest edge and farthest edge, and points in between, and displays what ever it sees. So even the noise tells us something. COOL!
You take a 150$ unit, you throw away half of it, and what is left is worth a 200$ OEM, single purchase.. Not sure if it applies here.
Massimo
http://www.fda.gov/radiation-emittingproducts/electronicproductradiationcontrolprogram/gettingaproducttomarket/default.htm
After that, we just have to track the contact info of each buyer, in case any issues pop up down the road they can be informed.
In the meantime, we have wait: