[keiths]

The issue of distance between blade and LED is an issue with ARC Pro and with the APB with original factory firmware (v0.85) that relies on both blade and LED sensors for lap counting. In that case, the optimum distance is 10mm (plus or minus 4mm) and the maximum is 24mm (see here: https://slotracer.online/community/showt...p?tid=1015).

However, if you have updated your APB firmware to v1.09, that lap timing glitch is not an issue. The only potential problem is the pivot effect - the further back the LED, the straighter the car needs to be as it crosses the lap sensors, lane-changer sensors and any pit lane sensors. A half straight after a curve usually does the job - maybe a full straight if you run non-mag.

Personally, I would go with the Slot.it SP15B rather than hack up a C8515 - it is a much easier job. Fitting the SP15B in the Revoslot will require two soldering points on the motor - that's all. The difference in price between the two chips isn't much - at Pendles it's £19.99 vs £14.95.

Oh, and if you haven't upgraded your APB to v1.09 firmware, plus PC race management software, you really should! See here: https://slotracer.online/community/showthread.php?tid=1056

Once again many thanks for the very detailed response!! To answer your point re the firmware, I am indeed running v1.09, so yes I don't need to worry about the sensor issues with APB- This upgrade is arguably the best and most vital operation to carry out for the C7042. Also fortunately when designing my permanent layout (I probably should post some pictures), where there are any lane changer tracks I always precede  these with at least a short straight, so hopefully IR LED/Guide blade distance won't be an issue.
Finally I am inclined to agree with you regarding the Slot it chip as being the best solution, but if I could bug you with one more question:- where is the IR LED located, or is it the case that you solder the LED to the chip using the separately sold IR LED pack that Slot it offer.
Once again many thanks for your very detailed reply, and thanks in advance for the answer to my last point.
Best regards...