SparkFun Forums

[mirlyn]

Some time ago I bought some components with a view to trying to build a timer/warning device so that a boat driver can monitor session times on the water. To be honest I neither have the time or, as quickly became apparent, the expertise, to do it . So I am posting on this forum in the hope that somebody may be interested in either taking on the project, or is able to put me in touch with someone who might. I would be happy pay a reasonable amount for somebody's time and expertise, and of course the components. Alternatively I am could trade some wakeboarding or waterski lessons for it If just the components could be put together to make a functioning circuit, I can get the whole thing put into a suitable box. If it can be built successfully, I will actually need two. I have been told that it should not be difficult but it is certainly beyond my capabilities. I am in the UK.

The device needs to have a countdown timer, with a display for the driver to see. It needs to trigger an audio and visual warning when getting close to a fifteen minute time limit and, when the time is up, to reset itself. It also needs to switch a fairly bright light which which will reflect these actions and can be seen from behind the boat . It was suggested that this could be based on an ARDUINO board. It would draw its power from the boat's 12v system.

The sequence would be as follows:

Timer is started by driver
The digital timer display starts to countdown from 15 mins in seconds
The boat driver will see from the display that the timer is running. A light bright enough to be visible to a person 20m behind the boat is illuminated so he/she also knows the timer is running.
At 12 minutes, the driver gets a visual warning, maybe the display flashes, perhaps once per second. The person behind the boat also gets same warning on their light. i.e. flashing once per second.
At 13 minutes 30 secs, the display flashes more rapidly and a buzzer also sounds for 10 secs. indicating to the driver that the time is almost up. The person behind the boat also gets the same warning on his light (i.e. rapid flashing) (may want to incorporate an audible warning too, loud enough for them to hear).
At zero, the timer automatically resets itself to 15 minutes and restarts. At this point the driver has the option to allow it to continue running without interruption for the next 15 minute period and so on, or he can stop the timer manually, when it will simply reset to 15 minutes and become idle until started again.
N.B. A facility which allows the timings to be customized would be very useful (presumably this could be done by changing the Arduino code?)

So thats it. Simples! (apparently)

If you think you can help me with this and I will be delighted to hear from you, even if you can do a circuit diagram and list of components needed, that would help.
Many thanks
Mike
mirlyn

[lyndon]

What if instead of a light behind the boat, the skier had a module around his wrist that would flash or beep when time was almost up?

[mirlyn]

Nice touch Lyndon. Problem is we would need a number as we are a commercial operation with up to 45 skiers a day, they would get lost, the skier could say it didn't go off, it could fall of. Think there are too many cons and not enough pros for it to be a workable option. thanks anyway. Mike

[lyndon]

A couple of the things you may want to specify exactly are the external light and the buzzer. It can be difficult for someone not in your position to know how bright the light must be and how loud the buzzer is so someone waterskiing behind a boat can react to it. I suspect that between the noise of the boat's engine, the sounds of the water, and distance, it may be difficult for the skier to hear a buzzer. Or at least, it would have to be so loud as to annoy the driver. The boat's electrical system is probably also very noisy, so that will impact the design.

Is there a limit on how large this "box" can be? Would something around, say, 8x10 cm be OK?

[mirlyn]

The buzzer is in fact for the benefit of the driver and our experience is that he/she can hear the bleeping from an electronic kitchen timer which we have used in the past. It would only need to trigger for 5-10 seconds as a distinct warning to him/her that time is almost up.
The light is another matter though. The skier would need to be able to see this in daylight, and occasionally in bright sunlight which we get once or twice a year!! I'll need to try a couple of things and get back to you later in the week with some idea. An enclosure 8x10 would be fine.
Thanks for you help again. I'll get back to you

[Mee_n_Mac]

The timer and helmsman interface is pretty easy. The only challenge I see is keeping the paying customer informed and happy. I wonder, given the likely bright daylight conditions, that a 'flip-dot' type display (like you see on 'emergency' highway signs) isn't the way to go ? Be it a 7 segment type or just an F1 type row of dots. Put it high on the towbar (you've got one ?), btw the speakers, and the skier/boarder should be well informed of his/her time remaining.
http://en.wikipedia.org/wiki/Flip-disc_display

Flip-dots.jpg

[jremington]

The Arduino forum has a "gigs and collaborations" section where you can solicit help. A lot of people in the UK frequent that forum.

[lyndon]

Are you still working on this? I reprogrammed one of my counter boards to do timing. Flashing three 1Watt LEDs is pretty visible even in bright light outside. I'll try to make a short video.