In case you're looking for an optical flow sensor, there is now one available in the DIYDrones store for a penny under $40.
This sensor is based on the ADNS3080 mouse sensor which is a good choice for optical flow because:
high resolution: 30 x 30 pixel frames meaning it can see features that lesser mice cannot
high speed: 2000 to 6400 frames per second update rate which contributes to better low light performance than other mouse sensors
SPI interface meaning it can be interfaced to many micro controllers and co-exist with other sensors
Other features:
- Intended to interface with a 5v microcontroller.
- 8mm lens with 11 deg FOV
- Standard M12x0.5 lens mount meaning you can replace the lense easily if required
Instructions for connecting the sensor to your APM/Oilpan are here.
Things to be careful of:
- Performs best outdoors in well lit environments
- Does not play well with Fluorescent lights (the blinking throws off the sensor)
- Needs a somewhat varied surface to see movement (plain carpets are not it's friend)
Uses including odometry and obstacle avoidance but I've used it mostly for horizontal position hold.
Note: integration with ACM and the existing GPS pos hold is a work-in-progress but should hopefully be completed in a few weeks. Here is a video of a slightly modified version of the ACM code using only optical flow (and sonar for altitude hold).
Inspiration and some technical help especially early on came from Marko Klein Berkenbusch and his blog on position hold with mouse sensor.
Hope you like it, all comments welcome!
Comments
Hi Randy,
My OFS is on its way, and am very excited about it. Though I wanted to see what the general feedback has been about the sensor. Also what and what not to expect from it? In terms of position hold accuracy, GPS etc?
Thanks!
ThomasB,
Yes, that was the intention but I was nervous about claiming it would work for 3.3V without ever actually trying it :-). Looking forward to hearing back from you when you've given it a try and then we will update the product listing. thanks!
@Randy
Thank you Randy. I had a look, and there is a true 3.3V Input which 'goes around' the 5V regulator.
So it will be easy to use for both: 5V and 3.3V solutions :)
@Denny,
Not sure about usingit for stabilisation. I've never heard of optical flow being used for that so I wouldn't want to give any false hope.
@Gomes, ThomasB, EllisonChan,
The eagle files are available now from the link on the diydrones store page (or you can get them directly here).
@Ryan C Smith,
I haven't implemented obstacle avoidance using optical flow although others have.
It's possible to connect more than one sensor although the wiring and the library would need to be modified. For the wiring, a separate wire would need to be connected from each sensor's NCS (chip select) pin to a a separate pin on the APM (or whatever micro you're using). I've only used the sensor for horizontal position hold (not altitude hold!) so haven't found any need for more than one.
Once the human vestibulary system stops working there is a technique that uses an implant of very small gyros and Acc. to give the sufferer some form of restored balance. Pioneered at Nicosia Uni.
Could the sensors not be used to view the camera LCD screen and then stabilise the mount.
Awesome, saw it in the store first and was gonna PM you (Randy) about your experience with such things ^_^
@Andrew. Everything works better with multiple sensors. Take the human body for example. We have a middle ear that is extremely sensitive to pressure changes, they regulate balance (IMU) Then all is assisted with visual compensation for that full 3D / Spacial perception, there are many more....
Thats awesome! The parrotAR can now suck it!
Thank you for your support.
Please, let us know when the eagle files get available so we can see why we're able to connect a 5V or a 3.3V micro without changing or removing any resistor on the NCS, RESET, MOSI, SCLK lines.
Thanks.
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