Go Kart onboard lap timer

Projects General Guidance
1

Hi guys, new to the forum!

I'd like to develop my own lap timer for my go kart, I race at a semi professional level so quality and what it can do and achieve has to be pretty good!.

I have been doing a fair bit of googling on the subject, there isn't anything serious about the subject, I've noticed a lot of people are using IR beacons to generate their laptimes rather than magnetic pickups! most seem to be playing with RC Cars.

Arduino appears to be the go for programming it and making it all work given how popular and common the programming language is now, I know nothing about the language though but I wont get too concerned about going there for the time being, just gotta work out the nuts and bolts on it first to see if it can be done!

Things it must have:

Magnetic Pickup for laptimes (all go kart tracks I know of have 3 magnetic strips)
Wheel Speed
Water Temperature
RPM

Things that I'd like to implement:

GPS
G-Force

The idea of gps is that it draws a map, and under analysis on a laptop you can use an overlay of google earth to analyse your driving lines.

All of this is very similar to the AIM Mychron device that's quite well known.

I have seen someone do something similar to what I am trying to achieve, they had all of their sensors terminating into a box that sat on the floor pan (you could always put this box anywhere rather than the floor pan!) with D serial connections (9 pin), which then had a d connection going out to it's own display box up on the steering wheel. I don't however know what programming it used to communicate with all it's sensors and what software he was using to analyse his data.

Other considerations for the device would also be vibrations and it would have to absolutely be waterproof!

I did find when googling a program called "loguino", but I'm not entirely convinced it's suitable for what I'm trying to achieve given the sensors I need to use.

Any direction on where to begin and guidance would be most appreciated!

Regards, Speedy

2

Guidance? First you need to decide if you are wanting to learn or just want to buy something.

Paul

3

Embarking on a project like this obviously requires the use of learning arduino... Yes I want to learn! lol

4

Arduino is a piece of hardware, the most common language to program it is C.

GPS will be nowhere near accurate enough to see driving lines (at least I assume this means you want to see how someone moved over the track left to right). You get typically 3-5 meter accuracy so you can just about tell whether someone is on the left or the right of the track but that's about it. For finding ideal lines and how far someone diverted you'll be looking for cm resolution. Definitely possible but I think it will involve placing beacons around your track at very precise locations.

G-forces: that's easy, use an accellerometer.

Water temperature: thermocouple or NTC or other kind of temperature probe will do.

Wheel speed: should be quite easy but not sure how to do this, depends also on where/how you can mount the sensors.

Laptimes: Arduinos are reasonably accurate in timing, for lap times (normally in the order of minutes) 1/100 or even 1/1000 second should be no problem. No idea about your magnetic strips, so no idea on what sensor would be able to pick that up.

5

Speedy:
I have been doing a fair bit of googling on the subject, there isn't anything serious about the subject

10 seconds of Googling.

Leo..

6

I haven't finished reading it all yet, but I dug this up 10 minutes ago: Kart Racing Lap Timer With LCD/LED Screen, Speed, Temp, Magnetic Pick Up - Project Guidance - Arduino Forum

It's pretty much exactly what I am trying to achieve!

7

wvmarle:
GPS will be nowhere near accurate enough to see driving lines (at least I assume this means you want to see how someone moved over the track left to right). You get typically 3-5 meter accuracy so you can just about tell whether someone is on the left or the right of the track but that's about it. For finding ideal lines and how far someone diverted you'll be looking for cm resolution. Definitely possible but I think it will involve placing beacons around your track at very precise locations.

Correct, however I don't think placing beacons all around the track would be ideal, especially if we're at an open race meeting!

8

So I have done some extra reading, certainly isn't impossible! now to decide on basic equipment.

Given how huge the task will be I think the easiest way to go about it is get the basics and then start adding sensors one by one as the programming is all nutted out, so on and so forth.

What's the best arduino board to go for? it appears that the mega would be the goer?

Display Screen, there are a LOT of small display screens going around, even this one for me is a bit small: https://www.sparkfun.com/products/11741

Would this screen be big enough to display everything once everything has been added?

Or is there an LCD Display big enough for which buttons can be added to it so it can be configured and flick through menu's?

9

Three such beacons should be enough (in theory, at least - triangulation gives you your location - in practice 4-5 would definitely be enough but more beacons should result in more accuracy), but you have to make sure you know exactly where they are relative to each other and the race track itself, and with exactly I mean at least cm precision, preferably mm precision. Your location calculation has an error that adds up all the errors in beacon position.

You could do this very well at your training track (of course you need to have the track mapped with a similar precision): place your beacons, then locate them by going to a few very exact spots on your track, and triangulate the beacons themselves. You don't need to know geographical coordinates, you just need to know where they are relative to one another and the track.
Next is of course the trouble of timing your signals, I guess you'll need high precision clocks in all beacons and your cart. After all you're going to time how long it takes for radio signals to reach the beacons. You'll have to look at millimetre wavelengths (1 mm wavelength = 300 GHz), as the wavelength limits the measuring accuracy.

This way you can get - in theory - to mm accuracy of where your go-kart is on the track at any moment. In practice it's going to be less of course, but 1 cm should be in reach. That's what I assume to be the accuracy you're looking for with your ideal lines, and squeezing out the last few tenth of a second of your lap times.

So much for the theory. I have honestly no idea on how this would work out in practice, or whether it would fit in your budget. Also I do have the strong feeling that this is out of the DIY scope.

10

wvmarle:
Three such beacons should be enough (in theory, at least - triangulation gives you your location - in practice 4-5 would definitely be enough but more beacons should result in more accuracy), but you have to make sure you know exactly where they are relative to each other and the race track itself, and with exactly I mean at least cm precision, preferably mm precision. Your location calculation has an error that adds up all the errors in beacon position.

You could do this very well at your training track (of course you need to have the track mapped with a similar precision): place your beacons, then locate them by going to a few very exact spots on your track, and triangulate the beacons themselves. You don't need to know geographical coordinates, you just need to know where they are relative to one another and the track.
Next is of course the trouble of timing your signals, I guess you'll need high precision clocks in all beacons and your cart. After all you're going to time how long it takes for radio signals to reach the beacons. You'll have to look at millimetre wavelengths (1 mm wavelength = 300 GHz), as the wavelength limits the measuring accuracy.

This way you can get - in theory - to mm accuracy of where your go-kart is on the track at any moment. In practice it's going to be less of course, but 1 cm should be in reach. That's what I assume to be the accuracy you're looking for with your ideal lines, and squeezing out the last few tenth of a second of your lap times.

So much for the theory. I have honestly no idea on how this would work out in practice, or whether it would fit in your budget. Also I do have the strong feeling that this is out of the DIY scope.

It's still something worth looking into in the future! Where can I source the beacons?

11

Google "millimeter wave location beacon"

The paid results give you options to buy them; the organic results everything else you need to know about them.