How SSD Works
Switching to digital is easy:
1. Replace your analog powerbase (pb), controllers, and transformer(s) with the digital versions
2. Add at least one lane changer track piece (lc) to your layout, and
3. Get at least one digital car
Simple!
Once you have the pb and controllers, you can add digital track pieces and cars over time, so you don't have to spend a bundle all at once.
Let's look at each of these components in turn.
The Powerbase - called a pb for short. This is the heart of the digital system. Like an analog pb, the digital pb provides power to the track and passes along control information to the cars. But that's where the similarity ends.
The pb consists of a 1/2 straight track section and a control box. There are two versions of pb, the c7030 six car, shown below:
and the four car, which is shipped in all sets as of late 2008.
Besides the obvious difference - one runs 6, the other 4 cars - the 6 car pb has lots of extra features. It counts laps and lap times, lets you select 6 different race modes modeled after different styles of 1:1 racing, and includes a data out port - called an aux port - so you can connect the pb to an external lap counter or a computer running any one of a number of third-party race management software. Only the c7030 6 car pb can be upgraded with PB Pro and Simple-H.
Both the 6 car and 4 car digital pbs power the track the same way - the design of SSD has not been changed since it was introduced. If you think about it, if cars can change lanes, then BOTH lanes must be powered at all times. The pb provides this power in the form of square wave AC. In the pb half straight section, the rails of each lane are connected together electrically, right to right, left to left. This means your layout is really just one big lane all the way around.
Information about how fast a car should go and whether to change lanes is modulated onto the AC power signal using pulse width modulation. A string of bytes is sent out for each car about every 20ms, whether or not a car ID - 1 through 6 or 1 through 4 - is actually on the track. If an ID has not been enabled, zero throttle and no lane change are sent.
If you put your ear next to the pb - sometimes even if you don't! - you can hear the buzzing of this data frequency, just like a 60 cycle hum from fluorescent lights.
The 6 car pb also allows you to select the braking mode for each car. Cars can use either dynamic braking - link - hich works the same as in the analog world - or brake by pushing a special button on the controller which works like an emergency brake on real cars, or use both types of braking.
The 6 car pb offers several different race modes: Qualifying, Grand Prix, Nascar, Endurance, Rally, Pursuit, and Arcade.
If you'd like to know more about the pb, take a look at the links under Powerbase in the Useful Technical Links
Overloads - Since the lanes are always powered up in digital, both pbs must have circuitry to shut down power in the event of a short on the track. When this happens, the LCD screen on the 6 car pb will dispaly "OVERLOAD". Resetting is easy, just push a button the pb. Before you reset, be sure to check the track for stray wire from car braids, screws that might have fallen out of a car, etc.
Timing and Scoring - the pb is connected to a half straight track section that contains 2 optical sensors. The first of these - the first one the car will pass over travelling from right to left - senses the car ID from the pulses of the IR LED on the bottom of the car. The second sensor senses the guide blade. If you install the pb the opposite way round in your layout, the car will hit the guide blade sensor first, and laps will be scored to the car that previously passed the IR sensor. It is the guide blade sensor that requires the use of black guides.
The Controllers
In analog racing the controller, the car, and a single lane of the track are connected together in a series circuit. You control the speed of the car by pressing the controller, which changes its resistance in the circuit and allows more or less voltage to be dropped across the car's motor.
In digital the controller is not in a circuit with the car and the track, it is only in circuit with the pb. You still vary the speed by changing the resistance of the controller, but it works just the opposite of analog. An SSD controller has a 0-5K ohm variable resistor inside. The more you depress the trigger to go faster, the HIGHER the resistance of the controller.
The pb reads the resistance of the controller and digitizes the throttle information in 64 steps, 0 to 3F in hexadecimal. Of course, there is a little tolerance in making the resistors used in the controllers. Sometimes you can get a controller where the resistance value does not go all the way to 5,000 ohms. In this case, your car will not achieve maximum speed. The PB Pro mod can overcome this problem by sensing the range of the controller's resistance values and calibrating the speed value the pb calculates so you do get max speed. This feature will also be available on the new c7042 6 car pb Scaley will introduce next year.
How would you know if your controller is 3F? - the easy way is to measure the resistance of the controller with a meter. If it read 5K ohms or greater at max throttle you're good to go.
Besides the throttle trigger, an SSD controller has two extra buttons, one for button braking and one for lane changing. These buttons switch in resistance values in the controller-pb circuit, an 8.2K ohm for lane change and an 18K ohm for button braking.
The control circuitry in the pb digitizes the resistance it sees at the controller and figures out what information to send to the car. The throttle information is contained in the first six bits of the data byte sent to the car. Bit 7 is for lane changing and bit 8 for button braking.
The Digital Transformer & 3rd Party Power Supplies (PSUs)
In Scaley analog, the wall wart puts out AC that is rectified in the pb into DC and DC voltage is used to power the rails. In SSD, the wall wart puts out DC that the pb turns into square wave AC to send down the rails.
The 6 car pb and the 4 car pb each have their own transformer, and about the only thing you need to know is use the wall wart designed for your pb.
The c7030 6 car pb has two power inputs, and it is advantageous to use both of them, either with two appropriate wall warts or with two inputs from a 3rd party power supply. The 6 car pb looks to see if it is getting power from both inputs and will output more power if it is.
Part numbers for making up leads for the 6 car pb are on
this page.
There are recommendations for 3rd party power supplies in the technical links.
If you are in the states, this is a good psu
Linky to Pyramid PSU. Be sure to get a PSU that has the right connectors for the mains in your country.
Unfortunately, using a 3rd party PSU will not greatly increase the amount of power to your track, because the power output capability of both the 6 car and 4 car pbs is set by their internal power components. It will give a slight benefit, because the output of the wall warts is not regulated, so the voltage tends to drop off as more amps are supplied.
To overcome this limitation, you can have the c7030 6 car pb upgraded with the Simple-H mod. If you do have the Simple-H mod done, you will need to buy a 3rd party PSU that can supply more amps than the Scaley wall warts in order to use the full power handling capacity - up to 25 amps - of the Simple-H board.
If you upgrade the 6 car pb with the Simple-H, our upgraders will set things up inside the pb so you only need one set of wires going to the pb from your PSU.
In using a 3rd party power supply, it is best to keep the output voltage set below 16 volts, especially if you are powering your LCs from the track rails (the way the LCs come stock). The components in the LCs are rated at 16 volts. Using a higher voltage may cause damage.