[Mr Muntarg]

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

If you can use lasers, why wouldnt you . LOL.

Great idea on the variable voltage . I should be able to knock up a circuit with a potentiometer and a little mini volatge read out . Once ive got the basics all flushed out that'll be a relatively easy addiction.

[Mr Muntarg]

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.

That's a nice neat solution . I have seen a few option for under track . I was bit worried about reliability especially with different colored guides. Be interested to see how you finding it . I assume this is essentially how the Arc Scalextric system is but i haven't investigated it. I found that wont read white pickup at all and is hit and miss on a few black ones .

[Mr Muntarg]

Over the weekend i made a bit of good progress on the base and have Lap-timing and circuit functioning. I originally fitted the IR LED included with the photo transistors , not realizing these needed 1.5v and blowing them straight away. Fortunately I've got loads of the 8 LED W2812 strips . Sticking a set of these on the underside of the gantry and setting them in Race Coordinator as Race state lights has the Timing working with a green light above. So far this has worked flawlessly but i may try and modify the Arduino sketch to have these permanently on in white. I've no clue how this will go but i'm sure i can find something online. 

Currently running 3 strips of WS2812 RGB leds with no resistors and no external power source . I'm going push my luck with this a little bit and maybe add another 2 or 3 for lights on back side of the gantry and maybe a strip on top of the base for other info.

I've not yet got the track power switching working but so far pretty happy

Anyway pics

   

   

   

[Phil Kalbfell]

The light source above the sensors needs to be on all the time, so just run them from a power source not thru the Ardunio.
We found the lights over the track a distraction so use some IR Leds sources from an electronics store.

[Mr Muntarg]

So far mostly good for the lap timer. The power supply runs 2 lanes no issue. The Jumpers work lovely and i'm about to knock up a second so i can daisy chain them together for extra security. I've got 32 LEDs running solely off the Arduino Uni. An Arduino Micro pro running 8 LEDS over the Photo transistors. 

BUT......I've got this strange issue of inaccurate lap timing. Between myself and my Wife , we have run roughly a 1000 laps over the weekend. And as far as we can both tell, The lap Audio has been triggering perfectly . But on very rare occasions the reported lap time could be 2-4 seconds faster or slower than the actually lap driven. If i was getting missed or extra triggers the lap audio would be sounding and i have been very careful to listen out for this . I'd also get multiple fast laps .or Slow laps would be above double the lap record. It's as though the internal clock of the hardware/software is getting out of sink, sped up or slowed down . 

I'm using a 3m USB extension as well as the USB plug on the front of the case . I'm going to try and eleminate both of these by running off an old laptop as my next port of call

[Scuderia_Turini]

Hello Mr Muntarg,
For powering LEDs providing the I-R source I have used USB Pin Breakout connectors. Convenient if there is a sare USB socket.

Leo

   

   

[Mr Muntarg]

Hello Mr Muntarg,
For powering LEDs providing the I-R source I have used USB Pin Breakout connectors. Convenient if there is a sare USB socket.

Leo

I've got some micro usb ones of those i could use if required but so far , touch wood .I've had no problem using the 5v output from the arduino uno to run 4 strips of 8 ws2812 leds aswell aswell as an Arduino micro pro with an aditional strip of 8 ws2812 leds . So 40 Leds in total . 

These are the Led strips I'm using
https://www.amazon.co.uk/AJMAKER-Strip-W...C76&sr=8-6