Marxpek

@mocbuild101Hihi you do not have to show me the formulas. That is just basic math anyone here should be able to do. My point was: how can we do this accurately? Cause what you mention just is not accurate. I tried to measure speed like that, unless you have a high speed camera (i do not) the result will vary a lot. Like i mentioned before. 0.1second is alot when going around 20kmh (doubt we will reach that but...) and what would prevent someone to make the track 10cm shorter? We wont notice on video. Measuring speed accurately just isnt that easy im affraid...thats why i bought the gps device (one big drawback.. doesnt work indoors..)

Yes that is the obvious way, but how to do this? in speed measurements, 0.1 seconds off, or a 10cm longer track can give quite big differences, unless we do a 1km track or something. 1 thing i thought of are sports fields, i have a artificial grass hockey field near me, that has set distances between lines, but artificial grass isn't really smooth, a indoor gym would be perfect, but i wouldn't know one where they would let me race a car. it will be a challenge to measure this accurate with everyone on separate locations without gps.

i do not see where this contest would be restricted to formula E type designs, i don't think that was stated, it was merely posted for inspiration it seemed to me, i read into this contest as: make a car that goes fast and looks good, by whatever means. I am for one not interested in mimicking a race car nor do i have the parts and will/can not participate if it has to be that kind of design, and i do not want to be restricted by a pre-set design. and what i tried to say about the paneling was: the rules should not state there has to be some kind of paneling, but it should be more along the lines of: it should look like a complete car and for that i picked a few (bad) examples ;)

Great idea, my cup of tea, speed records lovely! and a challenge to do it without RC-gear for once. But how would we measure speed? i have a small and accurate gps device that weights 40 grams, but i suppose i am one of the few here, so how can we test speed? Is this true? I'm pretty sure they still have the thermistor to keep things safe, just one with a higher setting, no idea how much higher though. I do not like this as a rule,i agreed with the no RC-parts but, anyone should either be free to choose whatever setup they like, or everyone should just the use exact same motor setup, i for example do have 2 Xl motors, but not 3x L-motor, but the L motor setup would have an advantage since it needs less gears to reach the same speeds and gear are resistance. Also would a servo be mandatory? Same story with the s-brick, the s-brick can handle much higher current then a normal receiver and they give no problems with sunlicght so i think s-brick should be excluded, since it's not Lego and a advantage to the ones that can use it. The "Paneling" idea is good but a bit subjective, when is a car a car? and why would i be obligated to use panels for that? i think that rule should state: It must resemble any type of car: aka, have a hood, doors, front window, roof (unless its a convertible...) stuff like that. Great idea, loving it, needs a bit of work but i will surely be participating!

I'm running out of idea's... if after checking all this we suggested and if you are still sure there is a issue, all i can think of is a break in the circuit board or wiring after this, but I do not know if that can be repaired...

@rkkm i also suggested this earlier on, it will probably fix the issue, but it should function without, the return to center hockey spring might be the other option, but it still does not explain the sudden change in the unit. One more idea that i had: the white reducer gear, the one you took out for the test and was showed at the end of the very first video, does that have any play on its axle? any damage to the teeth? and i think in the housing, which holds it in place, there is a plastic cap that acts like a bearing, (could also be on the axle of the gear itself, i do not recall) does that have any play on it?

Could be, i also had the feeling somewhere nothing is wrong here, but since @rkkm says it happened suddenly after a drive outside and the misalignment looks pretty big to me in that video, i can imagine there is an issue here. IF there are some metal shavings and dirt/ grease between these tabs, the sensor might think it is in the middle while (because there is a bridge of metal or conductive material between 2 or more tabs) and it will not take action to re-positioning , because it thinks it is in the middle.

@mocbuild101 don't you think rkkm's unit in the video has way more then 2-3 degrees off? Hihi sorry got a sucked in there ;D

Yes i know how it works, but if there is some dirt between 2 tabs, grease or whatever could cause it to think its connected, giving the sensor a wrong output and it might "skip" the middle tab. Not claiming this will surely fix the issue but since its opened and probably touched by greasy fingers and stuff, it is always a good idea to clean it up, just to be sure. I always clean electrical component when i open up stuff, chances are i'll never open it up again after and at least now i know its clean and no dirt and stuff can cause issues. This is an acceptable misalignment, i would say mine is similar, but the video @rkkm showed does have a lot than that i think.

Denatured Alcohol, also known as cleaning alcohol, not drinkable, most of the time about 70% or stronger, any cleaning supply store should have it, maybe you have some in a medical kit? Some medical kits also contain cloth wipes with alcohol in them for disinfection, these come in little tear-open bags, if you have a medical kit, there is a chance you have this, However, when cleaning fragile stuff like electrical components, alcohol is a good thing to have around, i have a small jar that costed me a few euro's. When cleaning with alcohol: take a small piece of cloth or cue-tip, make that wet with alcohol and just lightly rub the surfaces you want to clean, let it dry out a bit (vaporizes within seconds but i always give it a bit longer)

Did you clean all connectors with alcohol? the metal tabs seem not to bad, but there are some scratches. Are all 4 pegs on the drag-connector perfectly aligned? on the picture is seems as if the top one is ls slightly off compared to the rest, but that can be the camera angle too

Your English is perfectly understandable no problem! And i see what you mean now, the output gear has 4 little metal pegs, lets call these the "drag-contact" This drag-contact does it have some corrosion? (rusty, dirty or worn) you could try to clean em with alcohol and polish them a bit. The drag contact connects several metal tabs (the "7 positions" for example) on the electrical board, is any of these tabs damaged worn or dirty?, try cleaning them with alcohol and a cue-tip first, maybe even lightly polish them, but be careful it's thin metal. On this picture of yours i cannot see if the lines inside the tabs are damage or just light scratch marks, also dirt or grease between tabs could cause it to make false connections, so check all connecting elements (drag-contact and electrical boards metal tabs) for damage / (deep) scratches, maybe polish, and then clean with alcohol. Also very light bending the drag-contacts might help making better contact with the metal tabs, if 1 connection is not touching somewhere properly, steering is off, probably your issue.

That is great! that means your internal gears are in good shape, and since you can get the 7 positions in steering as well, i really do not see what can be a problem here at the moment, sounds as if everything works fine, is the steering failing in a tested car with a good setup? But i'll waiting for that video, maybe i'll get new idea's..

How much degrees can you turn the servo output without grinding the gears and without using any force? In other words, how much can the servo output freely move? (play/room in the system, because of old/worn internal gears) or: put and axle in the servo output, how much can you turn it by hand? (do not use any force)

Is the servo always uncentered to the same direction? Please consider that you are testing this without the housing, breaking the position sensor connection is easily done like this. how much space/play are we taking about here? is the play more then 1/16th of a full rotation both ways? Again: if i recall it correct (and until now i have ;D) the steering should have 7 positions: far left, middle left, light left, center, light right, middle right, and far right. (if you look at the top of the electrical board you can see the 7 positions for the contacts) if the unit is assembled, can you get the servo into these 7 positions? if that is the case, your contacts are fine (which is what i'm guessing here) If you cannot get the 7 positions, there might be something with the sensor connections, might be worth trying to slightly bend up the drag-connectors on the steering output gear for better connector, but be careful...

Checked the pictures and the video to me everything seems ok at first glance, motor starts to turn when you take it out of the center and contacts seems decent. Do you have a video of the exact problem that occurs? or what you are trying to fix? What is this problem? the video does not show it.

Good thinking! worth checking for sure!

mine also has about a millimeter of play left to right, that's just the wear on the gears i guess, but when used with the rc-front, which is loaded with springs to help to return to center, the problem isn't nearly as big. If i recall it right this cannot occur, the circular output gear has position recognition, which means that the gear on the servomotor, which drives it, will just keep turning when it senses a wrong position compared to the transmitters input (this causes the clicking sound when you stall the steering output on the rc unit, grinding gears). not 100% sure, but i think it works like that.

I chose to go without diffs right from the start with my 8048 crawler, The less non linear gears the better, was the idea behind it, surely some axles will be bent and steering isn't great, but i imagine when driving a real crawler you will face similar problems. When I went outside with it and surely wheels went up in the air and wheels where slipping all over the place, fighting to get grip on wet rocks, grass and sand, so i think no diffs is fine in crawlers but i'm no expert.., a diff lock would be perfect but a bit bulky in Lego.

For sure the creativity and effort award is yours! but please don't cancel feeding the toddler ;D I hope you can make it work! i really wanna see this in action! good luck!

This will be a great way to destroy Lego, i already managed to break a lot with the normal Lego rc module :) I used to be into RC planes and hovercraft and i still own everything to do this, (futaba 6 channel transmitter/receiver/servos, several lipo's, 2 ESC 30A and 2x 235W brushless motors) However i do not want to mix it with Lego, as i do not find it an achievement to do so myself, with the stuff i have i can probably make Lego fly for real... but i work within Lego's limitations and the "normal" Lego speeds already broke enough parts, but since you want i'll share what i recall. I think for what you want you can buy any transmitter/receiver you would like, just the ESC will be important, if i recall it correctly the ESC for brush-less motors do not work for standard DC-motors (Lego motors) and writing this i realize i can't actually do it with Lego motors myself since i have brush-less ESC's. So basically you will need a ESC for DC-motors which can handle 20 amps (for 4 buggy motors) which are fairly common in RC hobby, so it would not cost you that much i think, but do check if the ESC has a cut-off system for low voltage if you plan on using lipo's, this will prevent costly battery damage. You could use any receiver/transmitter set, but i do advice you not to get a cheap transmitter/receiver set, not all sets can be expanded with multiple receivers, and the more channels on it the better (and more expensive of course) 1 good set can last a lifetime and is worth the investment i think, better spend double/triple and enjoy it for the rest of you life then to replace it later on, maybe try to find a used quality set even.

@Ivan_M don't forget to order an extension cord to hook up the s-brick!

I have shunted a battery box to feed this speedy tracked racer with 2 buggy motors, besides that no confessions (however i already said i shunted it in the video, so does that count as a confession?) please do not mind the video quality... 2nd (out of only 6) video i made and i'm still trying to improve...but i had a lot of fun with this tracked racer and i think shunting the box for it was worth it.

2x IR-receiver plus 2 remotes is similar to what 1 s-brick can do (assuming you already own a smartphone), but costs are lower with the s-brick and it opens up more options. A buwizz would be even better since you will have a rechargeable battery built in with even more options. The s-brick/buwizz will also allow you to control more than 8 motors (ir only has 4x dual channel) If i would not have any controllers yet i would pick a buwizz, but i own several ir- receivers and 2 s-bricks, so i'll stick with this for now. (however i will buy a buwizz one day)

Fun little thing this is! Put an s-brick in it, loose the cab, and call it the next gen driver-less robotized excavator! Keep it up!