The Message
(design: August 2004)
(Pictures of my creations can also be found in my BrickShelf folder)
1. Background
We drive a rather small car with a maximum speed of 137 km/h. Because maximum speed in Belgium is restricted to 120 km/h this hardly causes any problem. Unfortunately there are lots of drivers who don't care too much about traffic rules. The thing that worries me most is "tailing": even at a speed of 120 km/h they keep less than 3 meters distance (how on earth can they avoid an accident if I suddenly have to hit the breaks?). Therefore I designed a sign which is hung on my rear window. The sign says "children on board" and can be turned invisible when I'm driving alone. If people see this sign they automatically enlarge the distance, not much but at least a bit more than 3 meters.
However there is one problem: You can't see the sign in the dark. Driving to Billund (approximately 1000 km) during the day with 3 little children comes close to insanity, that's why I prefer to drive at night with sleeping passengers. Another problem arises in Germany: there are no speedlimits. People with big fast cars don't have any respect for others: at 200 meters distance they already flash their headlights because they want you to clear the road for them. But how can you clear the road when you are overtaking a large truck? Can't they wait a few seconds? On top of all, with 4 passengers and lots of luggage (in the trunk of the car and even on top of the roof), acceleration slows down significantly.
Last year a German criminal tried to push us of the road (it was dark and he didn't know I had children in my car) because in his opinion I wasn't driving fast enough. That's why I want my "children on board"-sign to be visible at night too.
2. LED's
To make the sign visible at night I bought a small message board with LED's. Unfortunately there is no remote control: how can I turn it on when it's at the rear window with me sitting in front?
Solution: I can built something with LEGO!!
3. Construction
- I originally intended to use pneumatic elements: no power source required, to be triggered from a spot close to my steering wheel. Problem: I couldn't find pneumatic hoses of at least 5 meters long.
- The construction should be as small as possible; i.e. hardly bigger than the message board itself.
- I didn't want to use a standard 9V technic motor, because of its size. The only option left was using the micromotor.
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- Two switches: "on" and "off" (if it stays "on", batteries only last 6 hours).
- The micromotor is on the back of the message board.
- Notice the modified wire: a 9V electric brick on one end and a 4.5V/12V electric plug on the other end. According to Peeron there is a 9V wire of 5 meters long, but I don't have it. I made my own 5m-wire with the 4.5V/12V electric plugs.
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- Because black models are hard to photograph, I made rendered pictures from the MLCad-file.
- I only used pieces from set 8466, apart from the electric parts.
- The message board can be removed from the construction for easy replacement of batteries.
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- I attached a strip of Velcro to the battery box.
- The battery box is hidden under my seat (it's not on the floor, so it wasn't damaged when I spoiled half a bottle of water!).
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- The pole reverser is next to my steering wheel (also attached with a Velcro-strip).
- With a belt the construction is strapped tight to the back shelf.
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- I made it in black to make it almost invisible.
- The message was: "PLEASE KEEP DISTANCE: HEAVY LOAD - SLOW ACCELERATION"
We were lucky: there was hardly any traffic in Germany. I only had to use it once... with the intended result. Germans should not flash their headlights; I see their low-flying airplanes coming, but my car isn't fast enough.
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- The big advantage of using the micromotor was that it automatically stopped when friction was too high (the pole reverser could stay in its position). I could never have achieved this result with a standard 9V technic motor!
4. Epilogue
It won't always be the same message, because it can serve other purposes too. For example I can take it with me to LEGO club events to welcome the visitors.
The rendered images are created with MLCad, converted with L3P and rendered with POV-Ray.
We drive a rather small car with a maximum speed of 137 km/h. Because maximum speed in Belgium is restricted to 120 km/h this hardly causes any problem. Unfortunately there are lots of drivers who don't care too much about traffic rules. The thing that worries me most is "tailing": even at a speed of 120 km/h they keep less than 3 meters distance (how on earth can they avoid an accident if I suddenly have to hit the breaks?). Therefore I designed a sign which is hung on my rear window. The sign says "children on board" and can be turned invisible when I'm driving alone. If people see this sign they automatically enlarge the distance, not much but at least a bit more than 3 meters.
