Onboard chip/sensor transmitting speed over water back to skipper?
Attachment to skipper’s transmitter with digital readout in knots and hundredths
visible under open sky.
Skipper can adjust heading and sails to increase boat speed.
Sensor must NOT slow boat speed.
Technology must be available somewhere.
THINK ABOUT IT!
Frank Perry
Illegal for amya competition I do believe. Transmission from the boat back to the skipper is illegal. if it were legal, you would see pleanty of these devices in use, especially on larger boats.
~tb
~tb:
I do not want speed sensor for AMYA competition.
I do want it for sailing with four grandchildren.
Is it available???
Frank Perry
Should be able to use GPS technology. I have heard of it being used by model glider enthusiasts, and he has proposed a scenerio for model boats. Although it is limited in accuracy to 30 feet or so. But that should be enough for general direction and speed.
Doug Hale
What a coincidence, I have just picked up a secondhand Garmin Geko 101 Personal Naigator (gps) just to be able to record max speed of my new F100. It weighs only 88grams (3.1 oz)and waterproofed to IPX7 standards (1 meter for 30 minutes) its about the same size as a small mobile phone.
I saw this method used on a model landyacht or iceyacht (can’t remember which one or web site)
showing speeds of 24 knots.
“Although it is limited in accuracy to 30 feet or so”
Hmmm. In our world, 30 ft does make a huge difference in speed caculation. I would say that this limitation makes the GPS reading useless…?
30 ft wrong one way, then next reading might be 30 ft the other. Yikes…
I’m almost certain that transmission of info from a boat is not “generically” illegal in the AMYA; it may be in certain classes but in others it is legal because it is not prohibited. In the newer so far unrecognized classes it is definitely legal(F100, F48) and it is something that is DEFINTELY COMING but is not here yet. The best current solution is to use an inexpensive GPS like a Garmin ; it will record the highest speed encountered on any particular sail but you have to wait until you come back in to read how fast you went. This is usefull for seeing just how fast a fast boat really is!
Doug Lord
microsail.com
monofoiler.com
High Technology Sailing/Racing
I used a Garmin eTrex to record max speed on my K-1 iceboat last winter. I got it up to 33.3 mph. Some video images can be seen at: http://sobering.terracom.net/iceboating/K-1/Dec21-2002_LakeWingra/index.html
I’m sure someone could figure out a way to broadcast back a live signal, but it may prove to be more of a distraction to try to monitor it while watching the boat.
Bill K
I agree that the built in inaccuracy of GPS would make it problematic for getting accurate speeds from model sailboats. To the best of my knowledge there is nothing out there that fits your needs. A product that might work is one of the various speed readout units built for sailboards. ( I remember the same people who built the “Kestrel” wind meters used to market one.) But they would probably have to be adapted to transmit over a longer distance. People have also flirted with strain gauge wire sensors, but again no ready made product is available. A final easy idea that is available today is to buy one of the sports radar guns currently on the market.
Thanks, for all the suggestions.
However, the most readily available is the sports radar gun, but difficult to handle along with Xmtr sail & tiller controls.
With all the miniaturization today, somebody in the R/C fellowship with chip knowledge could make a lightweight saleable unit.
I want ongoing speed, not waiting until haulout.
I thought of GPS, but unit is too bulky & heavy for light R/C sailboats.
Never give up!
Frank Perry
Speed measured by GPS is one of the most accurate ways to measure true speed on a model ; any doppler system or in the water system is extremely inaccurate compared to a GPS and on foilers and most multihulls pretty useless.; radar guns even good ones are much less accurate than GPS when measuring a models speed…
Doug Lord
microsail.com
monofoiler.com
High Technology Sailing/Racing
Circuit plans needed of GPS speed for R/C boats…
1- Receive GPS signal on board boat.
2- Store GPS signal in temporary memory bank.
3- Calculate difference in distance/second of new signal from last signal in memory bank.
4- Transmit difference to receiver attached to skipper’s R/C transmitter.
5- Receiver displays speed in knots with digital read-out in hundredths visible under open sky.
by Frank Perry
Frank Perry
Maybe next year. I started pondering this with one of my elictrical engineer friends. We have a napkin sketch of the circuit. Idea is transmission range of about 200-300 ft in open air. Light wieght, wiring into the same amount of power available from batteries already in your boat. small readout on shore. Only problem . . . limited number of channels to relay info back, too much interference from other items in the environment.
~tb
Right now it could be done wit off the shelf components for under $1500(I think). You need a small video transmitter transmitting on 2.4ghz ,a small black and white camera and a Garmin GPS. Set the GPS for speed, aim the camera at the number and you have the on board side .On shore you need the 2.4GHZ. receiver and a very small monitor; the monitor can be placed in your field of vision fairly easily such that it moves with you.
A techno geek might be able to do a simple system by doing surgery on the GPS but would still need a pretty high frequency transmitter and receiver but could have an readout that clips right on your hat visor…Its so close close to easy to do tis that it won’t be long.
Doug Lord
microsail.com
monofoiler.com
High Technology Sailing/Racing
Right now it could be done with off the shelf components for under $1500(I think). You need a small video transmitter transmitting on 2.4ghz ,a small black and white camera and a Garmin GPS. Set the GPS for speed, aim the camera at the number and you have the on board side .On shore you need the 2.4GHZ. receiver and a very small monitor; the monitor can be placed in your field of vision fairly easily such that it moves with you.
A techno geek might be able to do a simple system by doing surgery on the GPS but would still need a pretty high frequency transmitter and receiver but could have an readout that clips right on your hat visor…Its so close close to easy to do this that it won’t be long.
Doug Lord
microsail.com
monofoiler.com
High Technology Sailing/Racing
<blockquote id=“quote”><font size=“1” face=“Verdana, Arial, Helvetica” id=“quote”>quote:<hr height=“1” noshade id=“quote”>Originally posted by lorsail
Right now it could be done with off the shelf components for under $1500(I think). You need a small video transmitter transmitting on 2.4ghz ,a small black and white camera and a Garmin GPS. Set the GPS for speed, aim the camera at the number and you have the on board side .On shore you need the 2.4GHZ. receiver and a very small monitor; the monitor can be placed in your field of vision fairly easily such that it moves with you.
A techno geek might be able to do a simple system by doing surgery on the GPS but would still need a pretty high frequency transmitter and receiver but could have an readout that clips right on your hat visor…Its so close close to easy to do this that it won’t be long.
Doug Lord
microsail.com
monofoiler.com
High Technology Sailing/Racing
<hr height=“1” noshade id=“quote”></blockquote id=“quote”></font id=“quote”>
Frank Perry
Too much bulk and weight with Garmin, video cam, etc.
Need mini circuit boards coat with wax to waterproof and extra weight substitute for ballast.
Select hi-freq low power low range communications band/channel.
We are in same folder…need to get on same page.
Frank Perry
Might be interesting to see if a bicycle speedometer could be used. They count the number of rotations then compute speed based on wheel size. Some can use very small wheels (~10cm I think) or a conversion factor could be used. An impeller could be fashioned to take the place of the wheel magnet. Some drag would be seen, but it would be very small. Many of the devices now have a wireless connection from the pickup to computer.
Example:http://www.nashbar.com/profile.cfm?category=&subcategory=&brand=&sku=6156&storetype=&estoreid=
The other option would be to use the sails as a giant screen to display the speed information. Of course that would give your fellow racer a distinct advantage!
Kristopher
Kristopher, you might be on to a doable solution.
Frank Perry
It is a more difficult problem than it seems.
The sensor is fairly simple to solve. Speedtech, a Swiss company with a vendor in the US, sells a speedometer system for sailboards. Their impeller, which is a basically a tiny plastic prop with a magnet imbedded in the plastic, is a good place to start. The rest of their system is too bulky and heavy for a model.
I believe telemetering is, or should be, illegal for racing – but it excludes itself anyway. If you put an impeller under your racing hull, it will be draggy, and the electronics add significant weight. My thought was to use it for tuning. Accordingly, I attached the sensor to a dinghy, and put the counting chip and the transmitter in the dinghy’s hull. I used a tugboat hull from MicroGlass in Buffalo. It is about 12 inches long.
The Speedtech system uses a coil under the board sailor’s feet. The impeller spins up, induces a pulsating voltage in the coil; on board electronics count the rotations and display the result in knots, mph, kph, whatever you prefer, on a readout clipped to the mast.
The coil is impractical for a model. I used a Hall Detector chip. It reads right through the fiberglass hull, and kicks out an nice, sharp waveform. (It contains a Schmitt trigger, if you are into this stuff.)
For the counter and scaling I used a basic stamp.
To get the count back to shore, I stripped a 27 Mhz FM pistol tranmitter from HiTech. Oddly, the PC board is nicely boat shaped, and slips right into the Tugboat hull.
How to modulate it? I replaced the joystick pot on one channel with a pot-on-a-chip, that is, a digital potentiometer. This works like an ordinary pot, only the wiper is incremented up and down by digital command, instead of by your fingers. The basic stamp processor counts the rotations of the impeller, and then drives the pot wiper up or down as a function of impeller speed. The R/C transmitter sends a signal as usual to a Hi-Tec R/C receiver on shore.
On the dock, a second processor chip measures the pulse width of the incoming R/C signal, converts it to a number (speed) and displays it on a little readout.
The net of it is, you can fiddle with the controls on your yacht, especially third channel controls like twist, backstay, or slot, and get an immediate readout on whether or not you have helped your speed.
It is not finished. The transmitting and receiving and all the processing electronics work on the bench (blowing on the impeller, running it under a faucet, etc, to simulate real boatspeed). But I have not yet put the tugboat into the water. The simple mechanical problem of mounting the hall detector is the latest sticking point, but I don’t doubt the system will work in practice.
Incidentally, you should probably have an FCC license to do some of this. But anyway, there is the basic system.
Best, Michael