[Mr Muntarg]

While researching this project i came across this forum and thought this may be of interest to people. Hopefully some far more knowledgeable people may be able to give me some advice along the way

I run a semi temporary 2 lane Scalextric sport track  with an arc one for timing along with a basic base and 2 power supplies. My plan is to build the following 


Single power base 
Single power supply
Photo-sensors for timing 
Blu tooth connection to PC
Plug in booster cables
Start lights
Call button/buttons

The plan is a base plate glued or screwed to the under side of a half straight , with a box on the side for all the electronics . An overhead gantry will house the IR emitter along with 16 addressable RGB LEDS. I'll be going along the well trodden route on an Arduino Uno for the PC connection along with a relay box to turn power on and off to  the circuit. This is largely unnecessary, but i like techy things and the relay boxs aren't expensive.  Ill be sticking with the sport controller 3.5mm jack plugs as there small and readily available. 

The main parts will be 3d printed for now. But i do run a CNC machine shop so may be from aluminium eventually. Picture below is first model files that are currently on the printer. They will no doubt get a complete re-design as i compact the electric down and hopefully make them a bit more visually appealing 



   

[Mr Muntarg]

I came in to work this morning to find the first part had printed perfectly and even better i hadn't made an cock up with the model files.  The half straight pops on perfectly and the Arduino sits nicely inside. All the bit will most likely be black eventually, but i have a surplus of blue for making 1st attempts . I'll also print on a higher resolution once design are finalized



   
   
   

[Mr Muntarg]

I'm hoping this power supply will be sufficient for 2 analogue lanes and to run the Arduino. Arduino's require 5v so ill need some kind of step down of the voltage. I could easily run another power supply , but i would like to keep it as neat as possible 

Power supply 
https://www.amazon.co.uk/gp/product/B09R...ZS1F&psc=1

Voltage step down
https://www.amazon.co.uk/dp/B099DPD1SH?p...ct_details

[JasonB]

This looks great.

[dazee]

Hi, will follow with interest.

Just a thought, the Arduino Uno only runs at 5v if powered over USB.  If you use the AC in you can power it using anything from 7-12v.  So if running your lanes at 12v you can power the UNO too using the single supply and needing no step down regulators.

I am rebuilding my track now, but had it setup for Race Coordinator too using a single power supply,  But in my case I powered the Arduino direct over USB from the PC as they sat next to each other anyways.

[Mr Muntarg]

Hi, will follow with interest.

Just a thought, the Arduino Uno only runs at 5v if powered over USB.  If you use the AC in you can power it using anything from 7-12v.  So if running your lanes at 12v you can power the UNO too using the single supply and needing no step down regulators.

I am rebuilding my track now, but had it setup for Race Coordinator too using a single power supply,  But in my case I powered the Arduino direct over USB from the PC as they sat next to each other anyways.

Ohh I wasn't aware or had forgotten at least that the UNO could run 12v . I've ordered a 15v DC supply so may not suit anyway . I was under the impression from a post on slot forum that usb power wasnt enough. But i guess its must be. I may just run it off that for now then. 

What are you using for lap sensor. I've ordered these https://www.ebay.co.uk/itm/115909533176. Don't really have any experience with photo sensors , but i figured can't be too far out and cheap enough

[Scuderia_Turini]

The Arduino will perform perfectly well using the 5 volts provided via the USB cable. An external power supply would only be necessary if you are running lots of LEDS from the Arduino.  I have two 5volt relays plus the five start lights running happily.  
For the LEDs in the "Light Bridge" I power those from a separate USB socket.

Your Arduino is missing the usual power socket that is provided for using an external power supply.

   

[Mr Muntarg]

I was hoping eventually to use a Bluetooth chip for communicating with the UNO so wouldn’t necessary have power from the usb , but I think for now till I’ve got it all working I’m going to park that idea . I removed the 12v plug on a previous project . I built a wind simulator for my sim racing rig . If I decided to use the 12v feed I’ll just solder wires directly to the board and save a little space 

What photosensors and lights are you using it’s the only part of the project I’m worried won’t work

[dazee]

For my main track before I tore it down I was using the 3du5c photo sensors and some little automotive LED bulbs in the overhead gantry - these were not of course powered from the arduino as the current draw exceeds the output of the arduino pins.  But you can still tap into the same power supply you use to run the arduino.

But you can use really anything that will return a basic high/low value back to the arduino.  I have also used the uxcell Slotted Light Switch sensors which are basically the same as what you have linked, but in a package you can mount in the track so you don't need a gantry - not really suitable for plastic tracks though as need alot of work to fit them.  Best for routed tracks.

Currently on my little test track I am using lasers as wanted to get triggers at multiple points and did not want multiple gantries.  And you know.... lasers!!! 

With the 15v power supply you also have the option of adding some of those little voltage adjustment circuits you can get that will allow you to tune the voltage independently for each lane and account for cars that run better on your track at a lower voltage.  These circuits typically drop your input voltage by 3v in order to run, giving you an output from 0v-12v

[Scuderia_Turini]

For several years I have used 5mm I-R LED receivers under the track surface with matching emitters overhead. Very recently I spotted sideways-facing LEDs and have been successfully trialling those as they fit nicely under the track surface (Policar). The receivers work well with white LEDs overhead so that will make life a bit easier when using temporary layouts and free-standing light-bridge. 

Leo

Ebay Linky:    https://www.ebay.co.uk/itm/225484518933

My proof of concept set up in Scalextric START track.