As the title says, I am looking to create a digital slot car ID programmer. I am using the Scalextric digital slot car system, and currently I have to remove all cars except the one I want to ID to link the controller with the car. The digital slot car system is very similar to DCC for model trains, where a digital pulsed signal is sent to the chip in the car (would be the engine in model railroading) telling the car to accelerate or slow down. The track power is continuous, but cycles between the two track rails to transmit the signals to the car. This way you can run 6 cars on one track as opposed to just one per track in analog systems.
I don't want to control the car, but simply push a button (I'll have a button for each car ID, 6 in total) to set the car ID. The car is programmed through the track by sending three "packets of information" . The packets follow the basic DCC format, but there is more information about the packet format if you are curious http://www.electricimages.co.nz/SSD_Control.ashx#tab9703 on the packet format. Voltage is 13.8v AC, so I will definitely need to amplify the voltage, although I was planning on using a separate power supply to provide the voltage and the arduino to do the signal pulsing. Here is a pic of the signal format…
I found this plan for a DCC command module… http://www.oscale.net/en/simpledcc, but I was wondering if I could simply use a Double BTS7960B 43A Motor Driver to send the data packets, or could I just use two high voltage transistors?
I am a bit of an electronics Noob, so any help would be appreciated. It seems that pulsing DC is very easy, but I am not sure how to handle AC.
rogerClark:
Does this project include an Arduino ?
Yes. The Arduino would be creating the data packets to program the car chips. The track runs on 13.8 volts, so there will need to be some way to increase the power from the Arduino.
Thanks for your reply. To my knowledge, and after posting on a slot car forum and googling extensively, this has not been done before. The link you posted was very cool, but related to an analog system, which is entirely different.
One of the key components of this system is that it is anti phase e.g. When one rail goes to 13.8v the other goes to 0v and vice versa. Any idea of how to handle that with the device you posted? Would I need two? Perhaps with an inverter gate? I will measure the current draw later tonight, but I am guessing around 1 amp or less. If I were trying to control the cars it would be much more, but I can't imagine that simply sending the programming signals is that power intensive.
I think you need to post more details of the rails and the waveforms
You seem to be saying that its a sort of AC that is appled to the 2 slot rails and that this is modulated
You may be able to use 2 FET modules, one for forward conduction and one for reverse, with a diode in series with each FET to stop the reverse polarity but you need need to post some more technical details.
Looking at one of the links you sent, it seem to imply that one rail was at GND and the other rail was switched between +13 and -13V, but I guess thats the same as saying that the GND rail becomes the +13V hence the other rail must be -13V
You will need to use a bridge of 4 FETS something like the attached image
The voltage source V2 on the left is the Arduino's pulse output
V2 is your 13.8V power supply
The resistor on the right is the track
Note The schematic is very basic example of what you'd need, you may need other diodes etc if the load is inductive. You are probably better off using Schmidt inverter in A1
