Analogue Shuttle Controller           Code: RK-ASCP
Requires 2 X 2 way detector boards RK-D2IR, RK-D2L, or RK-D2M



A PIC microcontroller in conjunction with four detectors generates varying pulse width DC voltages to control a locomotive running backwards and forwards between two end points.

Two detectors set the limits of motion of the locomotive, and the other two detectors set the slow down points.

Assume the locomotive is detected at the left hand end point. A voltage is applied to the track to cause the locomotive to move to the right. This voltage is gradually increased, (by increasing pulse width) up to a maximum, and remains at that level until the locomotive passes the slow down detector at the right hand end of the controlled section. The voltage is then reduced until it reaches a minimum setting, or until the locomotive reaches the right hand end point.

When the locomotive reaches the end point, all power to the track is switched off.

After a predetermined period (user selectable) the whole sequence is repeated with opposite polarity applied to the track so that the locomotive moves back in the reverse direction.

The user can select the minimum voltage (that which is just enough to make the locomotive move reliably) and the maximum voltage (corresponding to the desired maximum speed of the locomotive) by means of push buttons while in a setup mode.

The time taken to accelerate/decelerate between minimum and maximum speeds at the ends of the control section may be selected up to 15 seconds.

The time the locomotive waits at the end is also selectable, up to about 15 seconds.

The four values (min speed, max speed, acceleration rate, and wait time are set by selecting the quantity with a jumper, pressing reset, and pressing Inc(rease) and Dec(rease) until the desired result is achieved. Then the Done button is pressed, and the green LED will light if the quantity has been succesfully written to the microcontroller's non volatile memory. (See detail below left.) Pressing reset without selecting any of these results in normal shuttle operation.

The unit requires a 12 volt supply, and draws less than 100mA, plus the motor current of the locomotive. Track short circuit current is limited to approximately 1.5 amp.

The diagram below shows the main features and the layout of the detectors involved in setting up the unit for operation. (Diagram shown for light detector boards D2L, and for movement from left to right. Movement from right to left is similar, with D2 becoming the slow down detector, and D1 the stop detector.)

Current detection is not recommended for use with this kit.


Kit price for RK-ASCP: $42-50

Kit price for RK-D2x (where x may be IR, L or M): $22-50




A much simplified controller is available.


This uses a selectable number of diodes to reduce the input voltage and so control speed of the shuttle locomotive. The shuttle track is dividied into 3 sections, as shown at right, and outputs from the controller are connected to the four segments labelled 1, 2, 3, and 4. Timing is by a screwdriver control on the PCB.


Kit price for RK-QDSh: $32-50. No detectors needed.

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All kits available from :
Aztronics Pty Ltd       Phone 8212 6212
170 Sturt St,                     Fax 8212 4212
Adelaide, SA, 5000.                                
email:               sales@aztronics.com.au

Information:         David Crosby         david@railwaykits.net

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Last updated 3rd February, 2017.
(C) D. Crosby, December, 2011.