17th-Jan-20, 04:11 PM
That measurement matters for two reasons...
1) On all SSD or oXigen layouts, the LED does need to be over the centre line of the track (ie the slot) to trigger a lane-change sensor. That's also true on SSD tracks for a lap to be counted. Any lateral movement of the rear wheels (out of a corner, fishtailing on a straight etc) will move the LED off the centre line - and the further back the LED is positioned from the guide pivot, the further off the centre line the LED will be. For this, one inch (25.4mm) from the rear of the guide is a good maximum to aim for. Although Slot.it suggest a maximum distance of 35mm from the guide pivot to the LED (so about 20-22mm from the end of a Slot.it guide), DiSCA stalwarts (eg Tamar) have run 40mm (=25mm from end of the guide) on oXigen with absolutely no problems. It does depend a bit about the track characteristics, where lane changers are positioned etc.
2) With ARC Pro, the lap sensors in the powerbase rely on a two-step process - a horizontal IR beam is broken by the black guide and then a vertical sensor picks up the ID from the car's LED. With ARC Pro there is an ideal distance between the trailing edge of the guide blade and LED of 10mm - give or take 4mm. The optimum performance is in a range between 6mm and 14mm - and the absolute limit (measured by Dr_C) is 24mm, although the higher IDs will have had given up before then.
Keeping the maximum one inch as a rule of thumb, I would aim for less - especially if you intend using ARC Pro at any point.
1) On all SSD or oXigen layouts, the LED does need to be over the centre line of the track (ie the slot) to trigger a lane-change sensor. That's also true on SSD tracks for a lap to be counted. Any lateral movement of the rear wheels (out of a corner, fishtailing on a straight etc) will move the LED off the centre line - and the further back the LED is positioned from the guide pivot, the further off the centre line the LED will be. For this, one inch (25.4mm) from the rear of the guide is a good maximum to aim for. Although Slot.it suggest a maximum distance of 35mm from the guide pivot to the LED (so about 20-22mm from the end of a Slot.it guide), DiSCA stalwarts (eg Tamar) have run 40mm (=25mm from end of the guide) on oXigen with absolutely no problems. It does depend a bit about the track characteristics, where lane changers are positioned etc.
2) With ARC Pro, the lap sensors in the powerbase rely on a two-step process - a horizontal IR beam is broken by the black guide and then a vertical sensor picks up the ID from the car's LED. With ARC Pro there is an ideal distance between the trailing edge of the guide blade and LED of 10mm - give or take 4mm. The optimum performance is in a range between 6mm and 14mm - and the absolute limit (measured by Dr_C) is 24mm, although the higher IDs will have had given up before then.
Keeping the maximum one inch as a rule of thumb, I would aim for less - especially if you intend using ARC Pro at any point.
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