Slot.it oXigen Wireless Digital

Review by Doug T.

Slot.it oXigen

2.4GHz on the ISM band incorporating automatic channel hopping. Signals broadcast on 4 channels simultaneously to prevent data loss errors.

Slot racing digital system is compatible with existing analog tracks and lap counters. 20 cars per track, up to 4 tracks in one room. Open interface.

Two operating modes:

Hybrid O2: No PC required, uses existing track accessories (lap counters, stop&go, etc)

Pure O2: Completely PC controlled through radio interface

Hybrid 02: Works with or without PC; Completely compatible with traditional racing; Uses existing DS lap counters, Stop'n'Go, PCs.; Seamless Digital / Analog racing on the same track (during analog racing, oXigen lane changers stay straight and oXigen lap counting acts as a standard bridge, or the already existing bridge can be used).

Pure 02: Completely PC controlled; Maintains compatibility with analog tracks and racing (during analog racing, oXigen lane changers stay straight and oXigen lap counting acts as a standard bridge); No need for external lap counters.

How it works
SCP-1 cartridge talks to in-car module; In-car module drives motor and talks to LC

Hybrid O2: O2 lap counter talks to O2 interface to Lap Counters and existing Stop'n'Go box or PCs. DS lap counters, Stop&Go, PCs, etc work as usual to start and stop race.

Pure O2: PC talks to SCP-1 cartridge and (if optional smart LC module fitted on LC) to LC.

Note, the figures and specs below in some cases may be changed as the product comes to market. The figures are obtained by testing pre-production hardware and tested in a controlled environment. Depending one where the systems are used, results using production hardware may differ.

System features

Wireless frequency band	ISM 2.4GHz band *
Wireless lights	Controller can operate SP16 light board
Upgradeable (Wireless)
Maximum number of cars	20
Multiple systems in one room	4
Ghost cars/pace cars	Already built into the SCP-1 controller
Compatible computer systems	Windows XP, Vista and Windows 7 **
Race Management System (RMS)	oXigen RMS, PC Lap counter
*ISM - industrial, scientific and medical ** Slot.it say that they will release Linux and Mac versions later. The RMS will be open-sourced, and the dongle protocol will be disclosed free of charge to allow development by others.

Compatibility

Scalextric Sport Digital	*
Ninco Digital	( if rewired **)
Carrera Digital	( if rewired **)
SCX Digital
Custom routed wooden track	**
* Slot.it O2 Cars are recognised by SSD, but SSD power bases do not control the car. Also, a bridge rectifier is needed on the cars. Slot.it supply one that fits over the guideblade of the cars. ** Slot.it O2 conversion electronic board needed (for every lane change piece) - rewire Lane Changer pieces, keeping flippers and solenoids.

The LED protocol is based on Hornby's SSD system. SSD Power Base and lane changers detect O2 cars as if they were SSD's own. The power Base does not control the car though. Note that by design, O2 cars do not recognize Hornby's SSD Protocol: the compatibility is at the lane changing/car detection level.

oXigen is a sophisticated, high performance, yet reliable stand alone digital system. Thanks to an agreement with Hornby, the communication protocol between the car and the lane changer / lap counter is compatible with Hornby's own. oXigen is the only known commercial system being compatible with Hornby SSD. Hence O2 can use existing box stock Scalextric Sport Digital LCs. Besides, if you already have a Scalextric Sport Digital track, O2 cars can be programmed as SSD cars with ID 1 to 6, and they are properly detected by Hornby's PB. You can confidently buy SSD LCs knowing that you will put them to good use in both systems. If you need more than 6 cars, and more than 2 lanes, then the oXigen PC interface and Finish Lines can help you expand the system as they work seamlessly with SSD cars. In other words: oXigen cars 1 to 6 are recognized by SSD power base as cars 1-6; any SSD lane changer works with O2 cars (yes, all 20 of them!); O2 start/finish line and O2 lane changers are fully SSD compatible. oXigen technology extends the SSD environment to more than 2 lanes and 6 cars. oXigen cars and SSD cars can race together.

Car decoder

	Slot.it oXigen
Size	27 x 27mm
Current rating	3A continuous, 6A peak
Track power	9V to 18V
Photo-diode for LC detection	Built onto decoder
Hall effect sensor for finish line / pit lane detection
Upgradeable from PC (Wireless)
Price (June 2011)	AU$41 / US$44 / £27 / €30 *
* Prices here and elsewhere are rounded to the nearest US$, £ or €. They may not reflect importer or distributor prices. They do not include shipping.

Controller

Format	SCP-1 cartridge radio interface
Power	6.1V - 9V
Transmit power	10mW
Range (between controller and car)	Indoors 40m * outdoors 300m *
Number of selectable car IDs	20 Digital
LCD screen
Lane change button
Selective lane changing (see paragraph and photo below for info)
Brake button
Adjustable brake
Brake resolution	255 steps
Throttle resolution	255 steps
Adjustable speed curves	Selectable curve(s) / linear mode
Power reduction (Learner mode)
Battery saving	**
Encryption (Controller to car)	Unique controller ID
Driver Name	Set on PC
Frictionless Hall effect speed sensor
Upgradeable from PC (Wireless)
Price (June 2011)	AU$81 / US$86 / £53 / €59 ***
* Controller-car link. For the car-controller link used for simple lap timing: 8m. Data as communicated by Slot.it. ** Controller can be wired to track power and battery box has recharge circuit. *** For the SCP-1 oXigen cartridge only. SCP-1f controller (without any cartridge) is about €60 (so SCP-1f controller and oXigen cartridge together is AU$159 / US£170 / £108 / €119).

Selective Lane Changing: Slot.it oXigen has two lane change buttons: lets call them the outer button and the inner button for clarification (photo below).

If you have used digital on large circuits - say a club track or a championship track - you will realise that it can get confusing knowing which lane you want to get into especially if you are some way off from your car. Knowing which lane change pieces will take you to the inside and which to the outside can be confusing or difficult to see in the heat of the race.

Basically you know if you want to go to the inside or outside of the track as the concept of left and right is confusing from a remote driving position. So if you want to go to an inner lane, you press the inner button and likewise to go to the outer lane(s) you press the outer button. You can just hold one button to move right in or right out over a successive number of lane change pieces.

What a collection of controllers! I ran most of them at once testing with a few helpers. Excellent fun dicing for position on the BLST track.

Driving is smooth as soon as you have set your particular preferences on the controller for the car and track. The brake setting is quite sensitive and I found I had to dial it down to prevent the cars getting stuck on some tight curves - a bit less brake allowed them to drive more smoothly through these sections. Those familiar with the SCP-1 controller will appreciate all the regular features you are used to. Anything the controller can do on an analogue or digital track can be don with wireless - for example ghost cars are already built into the SCP-1f and thus they work on a wireless system.

The oXigen wireless cartridge only fits into the bottom of the SCP-1f controller.

Above, you see the antenna coming out from below the controller. Personally I don't like it, I'd much rather it we completely enclosed within the controller for protection. I can see this coming off unless somehow protected in the case or with another method.

Below are a couple of battery boxes. A handy on/off switch and indicator light help you see if it's on. Slot.it are producing rechargeable battery packs that will be able to be plugged into a charger for easy recharging. The controller can handle quite a variation in voltage

Above left we see the controller in a common driving position - all the main controls are on the left side. If you hold the hand brake button for a few seconds the controller/car ID and track number is shown. Above right is a look down (my right leg), controller in hand and battery box in the pocket - a comfortable setup.

PC interface (dongle)

I had a couple of dongles to test - both are essentially the same, just different cases. The dongle is quite large, not very practical for a laptop. Perhaps it can be attached to the top of the laptop screen with Velcro and linked via a short USB extender to the computer.

Below is my start/finish line. the LEDs you see are for the Scorpius system, but the Slot.it oXigen uses a different system. Magnets are positioned beneath the track and a Hall effect sensor in the car detects the passing over the start/finish line or the entrance to the pit lane.

A close-up of the top of the track shows a little hole that I have drilled 23 mm to the left of the centre line. This is to help position the magnet correctly underneath the track.

And under the track you see the magnet positioned over the little hole, perpendicular to the direction of the track above. Note, the wires next to the magnet are for the Scorpius Lane Brain LED - nothing to do with the Slot.it system. Note also the power connectors for my BLST track, the Analogue/Digital selector switch and the controller connectors for the analogue controller (when in analogue mode, the track can be used with one analogue car that drives the best racing line around the track).

The magnet needs to be positions with South facing up. The Hall effect sensor in the car can only detect one pole. Most Slot.it car magnets have South up as follows. I say most as there are a few that are polarised the other way around. Any magnet will do as long as South is up. My track is about 15mm thick and this magnet worked perfectly - it never missed a car. Obviously the car doesn't have to be 100% over the magnet as the field is quite large - and advantage of using this system. over a LED beam.

Below is the suggested configuration from Slot.it. The magnets F1, F2 and F3 work as start/finish line. P1 and P2 are the start and the end point of the pit lane area. The distance between F3 and P1 must be from 5 to 10 cm.

If you have a pit lane entrance that is a bit before the start/finish line, like my track design below, then you need to position the magnets as shown. The first magnet has to be F3and the second, P1 can be placed 5cm further on. The system slows cars down automatically when in the pit lane A neat feature so it is important to get that P1 magnet as close to the beginning of the pit lane as possible. P2 is then placed at the end of the pit lane

On to the software. Slot.it have a Windows based program that is still being tweaked. I have tested it on Windows XP, Vista and Windows 7. Other operating systems will be possibly supported in future as the software will be open source allowing other developers to integrate Slot.it oXigen into their Race Management Systems. PC Lap Counter will be oXigen compatible very soon, confirmed by Guy, the developer to me in the last few days.

Below is the basic screen. Car data in the middle. You can set the top speed of all cars with the top knob on the left. In a Pace Car scenario (no real pace car, but perhaps for a quick repair), all cars can be set to go even slower with the second knob on the left.

The tools on the right of the car data are used in long races to correct timing issues (cars not getting counted etc. - apparently it does happen).

Here below, I have started a 5 minute endurance race. Race time is set on the lower left.

Below, cars are 31and 33 laps into the race. Last and best lap times are shown. The speed is not shown as I'm using magnets on the s/f line and not using a DS or other lap counter.

Below, the pace car is called for. Cars are going slower.

Below, here is another view (second tab) showing cars in lap order (at the end of the race). Great if you are having a long race and you want to see quickly who is on top of the standings.

The software works well. I look forward to PC Lap Counter to get full race functionality and driver data etc. Using the magnets for start/finish line there is a slight delay in displaying the car time. The car travels perhaps one metre before the data is shown on the track - not much in the scheme of things, but you just have to get used to it.

If the screen is not refreshed due to a transmission error, the lap data is stored and passed on the next time around so no laps are lost. In all the tests I did (thousands of laps over the last month) I didn't see any lost laps.

Make sure you follow the forums for news and updates to oXigen system as there are updates and news quite often. There is also a great FAQ on the Slot.it website ( here ).

Below, a video of four of the test cars running oXigen Wireless Digital on the BLST track. Two cars are running automatically in Ghost mode. I am controlling The Sauber Mercedes and my son is driving another. With two drivers racing and two ghost cars, things are a little hectic on the track, hence a few de-slots and nerfing manoeuvres. Good fun though.

Check out our Introduction to Wireless Digital control.

June/July 2011