Thank you for your kind words and positive comments
That’s why I love LMR and the people here that make this site so interesting. I’ll update this post as the work progress and add some video when we get Whirligig in the water.
Awesome
The overall design of this project is so impressive, that I hesitate to bring up a tiny detail. But you choose to hang with us nitpickers. So here you go.
The micro switch seems flimsy. It might be triggered at the slightest touch. A bit of weed floating in or on the water will get entangled on the line an it will be hoisted up against the switch.
I love the super simple control system of the probe, the yoyo winch. And I’d hate to see it malfunction on a silly piece of algae.
I’d love to offer an alternative that is equally simple as the switch. The obvious thing would be a switch that is less sensitive. A macro switch.
The second idea would be a weight measuring device in the rod. Not as simple, but is might work. When the probe is lifted above the water, its weight will increase considerably. Should be fairly easy to sense. Perhaps even in the winch motor’s current draw.
Two thumbs up for this project though. Even if the switch jams on occasion.
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Thank you for your input
Thank you for your input Rik, and I do agree with you on the micro switch.
The fact that the micro switch might misfire ones in a while is not critical to the mission as all the data will be interpolated later. And all a misfire does is cut this trip to the bottom short and the next trip will probably be the complete length.
I’ve had several ideas on the switching, ranging from a whit shrink tube on the line and an optical sensor, to hanging a magnet on the line and use a reed switch for the trigger. But none seem practical and easy enough for me to build.
Your idea of measuring the weight when it is lifted clear of the water was new and interesting but more complex, and I don’t know the weight of future probes and was planning not to lift them out of the water as my motor can handle about 450g at maximum. The target weight for the probe submerged is at 200g.
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Switching from Arduino to
Switching from Arduino to FEZ domino should be very easy. OK, you have to learn a lot at the beginning, when switching to a new platform. But if you are familiar with .NET this should be an easy step. Porting the Arduino code will maybe a challenge, but most of the libs and drivers exists on both platforms.
The GPS Shield will need to be modified to work with the FEZ Domino, because the digital pins 2 and 3 are reserved for I2C bus. On the other side you have 3 Hardware UARTS on the FEZ domino available. It should also be possible to replace all the extra processors with it.
Good luck.
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I see
I understand that an interrupted trip down is not as serious as I thought *). I envisioned a bot in the middle of a lake with its probe dangling 10+ meter below its belly, not knowing what to do because the switch was jamming. *)
Could whirligig still travel with a dangling probe? )
) insert your own rude acronym here.
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You sparked an idea Rik !
Whirligig could be running even if the probe isn’t in ’park’ position, but you should get a warning in the control panel.
The winch board has the following logic built in to it.
One pin controlled by the Arduino triggers the oscillating and as long as it’s high the oscillating will continue. When the line goes low the run has to be complete before a ‘park’ signal is sent to the Arduino (a different pin goes high). Then Whirligig is free to move.
The plan was to only have Whirligig move when the probe is in its highest (park position) thus avoiding the line getting into the propeller.
But your comment made me think… what if the line breaks and we never get the park signal, or the probe/line gets stuck somehow?
Then it struck me, why not mount the fishing rod in the back? Then we are free to move even if the system is oscillating. A small detail, but it might make all the difference when Whirligig is left on its own for a week.
Thank you Rik !!
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I’m quite familiar with
I’m quite familiar with .NET and the Visual Studio IDE as I’m a professional programmer and have been working with ASP.NET sins its first release. I have only worked on web applications but the framework is not new to me.
I’m still waiting for my FEZ Domino from Sparkfun and looking forward to test it out. I have read some of the documentation and it looks like the FEZ has a great potential.
That said I had a look on their GPS driver and where not that impressed http://www.tinyclr.com/downloads/Extension/FEZ_Extensions_GPS.cs As far as I can see there is no validation of the checksum, nor does the object give you an indication of how old the GPS reading is so you could navigate on stale data. So one of the first things on my agenda is to write my own GPS driver (and maybe incorporate methods like Distanse_to and Cource_to from http://www.maartenlamers.com/nmea/ )
What I really hate with the Arduino is that the only debugging option you have is to print to the serial port, and when your serial port is used by some equipment it makes this option practically useless.
I’m really looking forward to get some hands on experience with the FEZ Domino and hope more LMR-users gets on the .NET micro framework as I think it’s got great potential for robot building.
Thank you Fritsl, you
Thank you Fritsl, you obviously keep a close watch on the forum, -and yes this project was what I wanted the thin wire for. As it turns out I think the new design will work better with a self-contained probe operating independently from the mother ship.
