Kart Racing Lap Timer With LCD/LED Screen, Speed, Temp, Magnetic Pick Up

Hello Everyone,

I am new to Arduino, and I am already impressed and excited.

My questions is, am I able to build a unit that measures and displays speed, water/coolant temperature, and lap times including Split Times based on 1 or more (split times) magnetic strips built into a race track. There are units available for purchase for example, Mychron 4, Alfano, however, I want to build/design my own.

If it is possible, what will I need hardware wise?

I am hoping to use a color screen of some sort, possibly touch screen, otherwise, I will need some buttons to skip through different options.

I want my unit to display Speed (0-200kph), RPM (0-20000rpm), Water Temperature ( 0-100 Celsius), Lap Times eg: 42.056 seconds. I possibly want to be able to enter different settings based on which track i go to..SELECT TRACK 1 - 3 magnetic strips or TRACK 2 - 2 Magnetic Strips. Id also want the option to display the following, not all at the same time, these options could be seen/flicked through after a race etc: Driver Name Date Time Last Lap Fastest Lap/s Speed

What are my options? Would a gps unit be the best way to get a speed reading? How can I get the RPM reading? All i really want for now is a list of hardware capable of running and recording this data.

At present as an example, I run a Mychron 4, the speed pick up is through a magnet stuck to my axle, and the sensor mounted just off the axle. The temperature is read through a 2 wire temp sensor that is bolted into my engine cylinder head, the RPM pick up is a single wire that wraps around my ignition/spark plug lead and the lap times are gathered through a magnetic pick up (I believe this is a reed switch) which is mounted to the floor pan of the kart.

Any help would be greatly appreciated! I have read the terms and conditions of posting, and assure you I have tried my hardest to adhere to the rules, and hope I have not too much or not enough information.

Regards. Adrian Sydney Australia

You have a cool project going, and unlike most on this site it is actually quite well defined! You will have a lot going on, but all of the individual parts seem very possible.

Plain color touch screens that you may find on the market are usually a bit much to run with an Arduino, but there are models that are made specifically to reduce the load on the Arduino. The catch is you loose some flexibility in the design on the interface. Your ideal solution might be something like this product from Sparkfun https://www.sparkfun.com/products/11740. If you want to save money in this regard, a character LCD and a few buttons can be put together for around $25. without too much trouble.

Speed: I wouldn't add a GPS, instead use a hall effect sensor to read the magnet that is already on the shaft.

RPM: See this forum post here about that http://forum.arduino.cc/index.php?topic=183038.msg1357519#msg1357519

Temp: The two wires are almost certainly a thermocouple. These are easy to interface with once you know how they work. http://learn.adafruit.com/thermocouple/overview

Lap Time: A reed switch or a hall effect sensor should pick up the magnetic strip. I like the hall effect sensor myself because it is solid state and is thus more tolerant of vibration and won't wear out.

Lastly, from a practical standpoint I would add one feature at a time instead of trying to do everything in the first prototype, but it sound like you are well on your way.

Hi Jroorda,

Thank you so much for taking the time to reply! Much appreciated. I have to say, the project has not even started. At this stage it is an idea and I am wondering what i need to begin. That screen is a great start thank you so much. Are there any smaller displays? Maybe around 3.2" - 4.0"?

Also, is it possible to encase the display screen as a standalone screen bolted to the steering wheel, with 1 output/input wire to another box which contains the 'brains' and to which all other sensors connect to. This can be mounted on the floor pan, eliminating excessive weight, bulk and wiring at the steering level.

Like i said, I'm extremely new to all this. My idea sort of goes like this.

Display Screen-----single wire-------main control box-----multiple inputs from different sensors eg: H2o temp, RPM, Speed, Throttle Position, Brake pedal position, Barometric Pressure, Ambient temp, Magnetic Pick up

Thanks again!

Nice idea and lots of possibilities. Start with the main box and simple sensors first as this as a new bie is big task. Baromatic and humidity take that as first challenge.

Once the box is ready and the serialmonitor can show you all data then start to think about sending it all to a display. At that time you might have been so far that the main box could send by bluetooth the signals to a simple bluetooth equipped smart mobile Phone which you connect to the steering wheel. (do not Phone and drive .... :-) )

When you project is finished you can also store all data on a SD card so you can later examen all data.


Thanks for your time Paco.

I’d prefer not to spend money on things I won’t use such as the blue tooth you mentioned. I suspect that to be able to do that I would need a blue tooth module which I probably will never use after testing my idea as per your suggestion

Can anyone suggest the best possible main board/brains/arduino unit that will be able to run all this. A specific suggestion such as the reply by jroorda earlier with the link to his suggested screen would be fabulous.

Some pointers as to why you suggest this particular board would be fabulous too. Thanks

I would start with an Uno or something similar. Depending on the exact choice of components you may run out of pins or another resource, and in that case you can move up to a Mega or something like that. Having an Uno around for development will still be very useful even if you need a bigger board for the full product.

If the physical size of the board becomes an issue in the future I would then look into something like the mini with a smaller profile.

Thanks again mate.
Attached is a very basic diagram of what I would like to read/record/display.
Are you able to possibly list what components I require ensuring they are compatible so I can price up the basic components before looking at any coding.

ambient and humidity :http://www.aliexpress.com/item/DHT11-Digital-Temperature-And-Humidity-Sensor-Moudle-Probe-For-Arduino-FZ0068-Free-Shipping-Dropshipping/720801986.html ambient only > LM35 Coolant engine temp depends on how to connect. Baromatic https://www.sparkfun.com/tutorials/253 rpm/speed depends on how to read optical or hall sensor. time> RTC http://playground.arduino.cc/Main/DS1302

Main thing first is to read and read as much as info on the web for all sensors and their connect like I2C, SPI, Digital or analog. Make a whishlist and connection type then come back. Start to understand coding and libaries as there is no ready to go software. Code step by step one sensor at the time and expand one by one.


What backbone posted above looks good.

Ambient Temp & Humidity: I have used the DHT11 and have been quite impressed with it, so you won't go wrong there.

Coolant Temp: Use a thermocouple, type K is the most common. If you already have two wires coming from this area you can bet that there is a type K thermocouple on the other end. If you need to buy one here is a link https://www.sparkfun.com/products/251. To get good data you need to amplify the signal before you read it with the Arduino's ADC. There is a link to an amplifier off of the page above.

As for the magnetic rpm and lap time sensing, get yourself a few hall effect sensors http://www.mouser.com/ProductDetail/Honeywell/SS451A/?qs=%2fha2pyFadujv2DegI%2f6G%2fg5sFVAZv3HpBfdL93OF9b4%3d. I know you would probably like to get everything from the same place, but Sparkfun only sells a latching hall effect sensor which would require you to add a second magnet.

hello! any news? have you completed the project at the end?

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