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mwnilsson

Fastest LEGO Technic Car!

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2 hours ago, Sariel said:

, draw marks on a road 10 meters apart and film how fast your car goes from one to the other at top speed, then do the math? This way you don't need to put anything on the car, the camera can simply stand on a side.

Haha...I guess I need to work on my writing and explaining skills...

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8 hours ago, TheMindGarage said:

The pneumatic one looks really cool! Are the parts all stock (apart from the Fanta airtank of course)? If so, I'm impressed...

Thanks! no that one is heavy modified! the cylinders are drilled at 2mm on intake/exhaust-ports and switches are drilled and the "step" in them is removed. If I had a more reliable airtank (scuba) and a air pressure ragulator it would be seriusly quick! According to http://www.nico71.fr/otherpages/LPEtools.htm It puts out 88W at 3bar@1370RPM (unmodified would be like ~100rpm and 3w)

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Got some competition on youtube! A guy say he drove 29,44Km/h. So I had to break the 30 mark before someone els did!

Simply put a V2 reciver and PF Battery Back om my last car and it did the trick so 2 remotes one for each motor :)

 

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Not to doubt but you should drive the same road in the other direction and average the two readings as it looked a little downhill in the vid. Just saying ya know, as one is claiming a world record with so many variables.

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25 minutes ago, MangaNOID said:

Not to doubt but you should drive the same road in the other direction and average the two readings as it looked a little downhill in the vid. Just saying ya know, as one is claiming a world record with so many variables.

Just to take all the fun out of LEGO of course as we're adults n all. :sceptic:

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14 hours ago, MangaNOID said:

Just to take all the fun out of LEGO of course as we're adults n all. :sceptic:

its a loading dock for trailers so the slope is from the house and out for draining. If you see on the video I was driving alongside the house and it is super flat apart from some irregularitys in the payvment. And the world record claiming is just for fun it rubs folks the wrong way... But i havent heard anyone gone faster:tongue:

Edited by mwnilsson

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On 3/31/2017 at 0:38 PM, mwnilsson said:

BTW is it safe to use the other 2 ports on the recivers to a second engine?

I never have tried that. I only had enough of the old 9v Wires to combined for one Motor connection.

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He has posted his video of the 29,44Km/h (GPS) Car and it has the same gear ratio as min but a slightly bigger wheel But everything els I think is wors than my 27Km/h Car: The surface of the track he drives on, The back wheels is like the most rolling resistant ever of a lego tire ever, The overall size of the car is bigger. What do you people say? @Boxerlego @MangaNOID @Horace T @Sariel At least this woud suggest that my speedcomputer isent showing more speed than my cars are driving!?

 

Edited by mwnilsson

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One quick suggestion would first of all to remote all the GPS stuff, it's not totally reliable and it only adds un-needed weight to the car. Just measure in advance a 100mt lane for example, mark start and end of it, and try to cross this segment as fast as possible and measure the time. With time and lenght, you calculate the speed. And as @MangaNOID said, the track has to be crossed in both directions usually, at least this is what they do for the ground speed record.

Then, it depends if you want a "pure lego components" record, so using the IR receiveer, otherwise I'd remove even more weight by replacing battery and receiver with a buwizz, that also has much more range.

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Look, I'd love to quit this discussion. If you reject GPS as inaccurate in favor of a $20 Lego toy that's 17 years old now, it's your choice. Personally, I'm sticking with GPS, but to each his own.

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Not sure who are you referring to, but if it's my post, I said and I think that a meter and a stopwatch may be more precise, especially on these short distances.

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7 minutes ago, dellock6 said:

Not sure who are you referring to, but if it's my post, I said and I think that a meter and a stopwatch may be more precise, especially on these short distances.

That's utter nonsense! When meassuring smal things every error you make is proportionally bigger! Just take into account the feedbackloop in your body: Even if you're prepared to measure date it takes about 0.3 of a second to hit that damn button on the stopwatch. 

For this application GPS is sufficient. Or you have to ramp up the distance to 1 km or 1 mile to get a sufficient measurement.

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1 hour ago, Sariel said:

Look, I'd love to quit this discussion. If you reject GPS as inaccurate in favor of a $20 Lego toy that's 17 years old now, it's your choice. Personally, I'm sticking with GPS, but to each his own.

I dident mean i regect gps just that it isent perfect. And now that another person has made a car whit simular futures as min and got better results it suggest that my speedcomputer isnt so inaccurate. 

1 hour ago, AkiyamaWataru said:

That's utter nonsense! When meassuring smal things every error you make is proportionally bigger! Just take into account the feedbackloop in your body: Even if you're prepared to measure date it takes about 0.3 of a second to hit that damn button on the stopwatch. 

For this application GPS is sufficient. Or you have to ramp up the distance to 1 km or 1 mile to get a sufficient measurement.

If you film the 10m stretch you dont have to stopwach it at 24fps you could time it accurate to 0.04sec just going frame by frame on your computer

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39 minutes ago, mwnilsson said:

I dident mean i regect gps just that it isent perfect.

Nothing is perfect, and GPS is far more accurate than the Lego speed computer, which, again, is a cheap toy made back in the year 2000. Look, the only way to get an accurate reading of RPM with Lego is to use a Mindstorms motor and a Mindstorms brick, but that's a lot of extra weight.

Again, it's your choice. I simply suggested something that I think is more accurate, but if you don't like it, it's fine.

Edited by Sariel

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1 hour ago, mwnilsson said:

If you film the 10m stretch you dont have to stopwach it at 24fps you could time it accurate to 0.04sec just going frame by frame on your computer

If you wanted you could set up a photocell-system to measure the time. You then get a timing accuracy of less then a mili-second. But for the convenient use it's easier to use a GPS-Based data tracker.

If we want comparable measurements we should put ab a reglement to specify what is a valid speed measurement.

 

edit: word change and typo

Edited by AkiyamaWataru

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4 hours ago, AkiyamaWataru said:

That's utter nonsense! When meassuring smal things every error you make is proportionally bigger! Just take into account the feedbackloop in your body: Even if you're prepared to measure date it takes about 0.3 of a second to hit that damn button on the stopwatch. 

For this application GPS is sufficient. Or you have to ramp up the distance to 1 km or 1 mile to get a sufficient measurement.

Hey, we don't even know each other, so calm down on terms please. We have different opinions, and everyone is trying to explain their reasons. No one here works for the Guinness book of records so can tell what the best technique would be. We are just discussing, and I used the 100mt example because compared to the size of a lego car is a significant measure, and for example athletes compete on the same distance and we are pretty good at measuring the exact time. If you want millisecond or millimeter precision, not even GPS can give you that.

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I have a Bushnell Velocity Speed Gun.  You could use one of those to measure speed.  It's simple, accurate, and there's nothing to add to the vehicle.

 

 

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2 hours ago, dellock6 said:

Hey, we don't even know each other, so calm down on terms please. We have different opinions, and everyone is trying to explain their reasons. No one here works for the Guinness book of records so can tell what the best technique would be. We are just discussing, and I used the 100mt example because compared to the size of a lego car is a significant measure, and for example athletes compete on the same distance and we are pretty good at measuring the exact time. If you want millisecond or millimeter precision, not even GPS can give you that.

I'm sorry if I was rude. For me it just sounded like replacing an unprecise form of measuring the speed with a more unprecise one. Your proposed way would be good if combined with a different measurement stile. And maybe one should allow the inclusion of a form of runway to accellerate to top speed.

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13 hours ago, technic_addict said:

@mwnilsson   have you tried connecting the batteries in series as mentioned by @Boxerlego?

No need a second v2 reciver for it to work ok with buggy motors

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Sorry for going a bit off the topic, but I found something helpful for those willing to measure speed with GPS. The new Hero 5 GoPro camera has integrated GPS and can record speed while filming, and if you use GoPro's Quik video editor, you can actually put the realtime speed reading on the video itself. Like this:

 

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Hey that's my car!

I'm new to the forum, nice to see you already found my video. @mwnilsson seems we already met online via youtube!

Gps.. yes.. or speedguns even better.. but iv'e heard they can be inaccurate under 30 km/h, does anyone know?

also check my rebuild with steering, standard 2 buggy motor setup and a well designed front end for high speed driving, works well!

Edited by Marxpek

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thank you @mwnilsson sure we will keep in touch! nice way to "spy" on each others work ;) have you tried to improve your design any further? would be fun to keep pushing forwards ;) i already considered that double voltage design earlier, i suppose it could work with 2 switches in stead of the ir-receiver aswell but i never looked into it because i feel that it will be risking losing the buggy motors because of the voltage (they have internal resistor to limit the current, but it think the voltage can actually do damage, not sure tho)

Maybe ill try the booster battery box setup i mentioned on youtube if i ever get a second rc unit, seems risky tho..

i addition to that idea: can the Lego led's be used as real diodes in that situation? I have no clue if that kind of wiring is possible, but a led is a diode letting the current flow only 1 way, could make the booster idea box work...

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