Controlling Tortoise Machines with Momentary Contacts and a Diode-Matrix By Jerry Hoverson, MMR 15 November 2008

Controlling Tortoise Machines With Momentary Contacts Why the Tortoise switch machine motor in the first place Easy to install Reliable Rugged Provides slow, quit movement of points Provides constant pressure to hold points against stock rail Provides 2 sets of contact points Frog polarity control Panel indicator lights Switch indicator signals Has become the hobby standard for remote control of turnouts 15 November 2008

Controlling Tortoise Machines With Momentary Contacts The biggest disadvantage of the Tortoise switch machine motor is that it requires a constant, reversible 9-12 VDC power source. 15 November 2008

Controlling Tortoise Machines With Momentary Contacts So what happens if you try to control that turnout from more then one control panel with that constant power source? A SHORT! 15 November 2008

Controlling Tortoise Machines With Momentary Contacts Enter the 556 circuit! 556 15 November 2008

Controlling Tortoise Machines With Momentary Contacts Where you can control the Tortoise with MOMENTARY devices Momentary DT Center Off Toggle Switch Momentary Pushbuttons - S 8 R 1 + 556 15 November 2008

Controlling Tortoise Machines With Momentary Contacts Here’s the circuit diagram for those who just have to have one. 300 ohm R1 2.2K R2 10K R3 + 12 VDC - 12 VDC IC1 LM556-B 6 2 1 7 5 LM556-A 14 8 13 9 12 C1 10uf + - D1 D2 Set Reset Tortoise 300 ohm 15 November 2008

Controlling Tortoise Machines With Momentary Contacts OK, lets look at how we would install this on a simple track arrangement. Track A Track B Track C Track D MAINLINE 15 November 2008

Controlling Tortoise Machines With Momentary Contacts One method is to mount the 556 circuits in one “master” panel and then connect additional “slave” panels to the master. Slave Control Panel Master Control Panel 556 - S 8 R 1 + 15 November 2008

Controlling Tortoise Machines With Momentary Contacts What’s good and what’s bad about this method of installing? PROS 556 Circuit is accessible inside the control panel not under the layout Multiple circuits can be ganged together Single board Single power connection with Positive and Negative 12 VDC buses Only 2 wires going from main panel to Tortoise CONS Takes up real estate inside the control panel Depending on other items may be difficult to get to connectors Large number of wires going between each panel Hard to add another tortoise once complete 15 November 2008

Controlling Tortoise Machines With Momentary Contacts Here’s a “ganged” set of 556 circuits in a control panel. 15 November 2008

Controlling Tortoise Machines With Momentary Contacts Let’s look at a general setup using a “master” panel. 2-Wire from Master Panel (1 & 8) for Tortoise movement Tortoise Tortoise Tortoise Tortoise 16-Wire from Slave to Master (S & R) for control of each circuit (1 & 8) for LED indicators for each circuit Slave Master 556 556 556 556 12 VDC 2-Wire (+ & -) 12 VDC 15 November 2008

Controlling Tortoise Machines With Momentary Contacts Another method is to mount individual circuits near each Tortoise Machine Control Panel B Control Panel A 556 - S 8 R 1 + 15 November 2008

Controlling Tortoise Machines With Momentary Contacts Why use this method of installation? PROS Frees up space inside the control panel Multiple circuits can be ganged together if tortoises are close together (i.e. a yard ladder) No massive bundle of wires between panels Simple to add another circuit between panels CONS Takes 4 wires from each panel to the tortoise Takes 2 wires to supply power to each circuit Set up as a bus and daisy chained 15 November 2008

Controlling Tortoise Machines With Momentary Contacts Here’s an individual circuit mounted near the Tortoise Machine 15 November 2008

Controlling Tortoise Machines With Momentary Contacts Let’s look at a general setup using the individual 556 circuits mounted at the tortoises 4-Wire from Slave (S & R) for control (1 & 8) for LED indicators 4-Wire from Master (S & R) for control (1 & 8) for LED indicators 556 556 556 556 Slave Master 12 VDC 2-Wire (+ & -) power bus 15 November 2008

Controlling Tortoise Machines With Momentary Contacts Now let’s take this a step further and implement a Diode-Matrix to control several turnouts with a single button. Otherwise known as “route control”. Track A A Track B B Track C C Track D D MAINLINE E 15 November 2008

Controlling Tortoise Machines With Momentary Contacts To implement a Diode-Matrix you simply wire each button to an input on the matrix and the outputs of the matrix to the “S” & “R” connections on each 556 circuit We’ll start by numbering each turnout If we push button “A” then 1=R, 2=S, 3=S, 4=S The unmarked direction is then the “R” or Reset position A Then we need to determine which direction is Set “S” or the default position S 4 B S 3 C S 2 D 1 S Mainline E If we push button “E” then 1=S & we don’t care about the others 15 November 2008

Controlling Tortoise Machines With Momentary Contacts Let’s take a few minutes and set up our Diode-Matrix S R 4 A B C D E 3 2 1 if we push Button “D” 1 goes to “R” 2 goes to “R” 3 we don’t care 4 we don’t care if we push Button “E” 1 goes to “S” 2 we don’t care 3 we don’t care 4 we don’t care if we push Button “C” 1 goes to “R” 2 goes to “S” 3 goes to “R” 4 we don’t care if we push Button “B” 1 goes to “R” 2 goes to “S” 3 goes to “S” 4 goes to “R” Remember, if we push Button “A” 1 goes to “R” 2 goes to “S” 3 goes to “S” 4 goes to “S” A B C D E 1 2 3 4 S R 15 November 2008

Controlling Tortoise Machines With Momentary Contacts So let’s wire up the Diode-Matrix with the 556 Circuits Connect the buttons and the 556 circuits to ground 556 #1 - S 8 R 1 + 556 #2 - S 8 R 1 + 556 #3 - S 8 R 1 + 556 #4 - S 8 R 1 + Connect the 556 circuits to + 12VDC + 12 VDC Connect the buttons to the matrix inputs Connect matrix outputs to the 556 circuits S R 4 A B C D E 3 2 1 A B C D E And last connect the “1” & “8” outputs on the 556s to the tortoise machines 15 November 2008

Controlling Tortoise Machines With Momentary Contacts OK, now that you’ve seen all the wonderful things a 556 circuit can do for you, what does it consist of and what does it cost? Parts List Part Nominclature Price   2 x 2.375 circuit board $ 0.59 14-pin solder IC socket $ 0.20 C1 10uf Electrolitic Capacitor $ 0.16 D1 "Set" Red LED $ 0.17 D2 "Reset" Red LED IC1 LM556 $ 0.89 R1 2.2K Resistor $ 0.12 R2 "Set" 10K Resistor R3 "Reset" 10K Resistor S1 3-Socket Connector "+", "1", "R" $ 0.39 S2 3-Socket Connector "8", "S", "-" $ 3.32 15 November 2008

Controlling Tortoise Machines With Momentary Contacts Here is what individual 556 circuits for mounting near the Tortoises looks like 15 November 2008

Controlling Tortoise Machines With Momentary Contacts The 556 circuit used in this presentation was developed by Rob Paisley Rob has published a lot of model railroad circuits, for example: Stall motor turnout controls like this one (several variations exist) Automatic grade crossing controls Traffic light control Infrared detectors Block occupancy detectors His web site: http://home.cogeco.ca/~rpaisley4/CircuitIndex.html#index If you are interested in building this circuit and trying it out there are handouts available that include: Electrical diagram Parts list Parts layout diagrams Detailed step by step instructions on building the circuit 15 November 2008

Controlling Tortoise Machines With Momentary Contacts Q & A 15 November 2008

Controlling Tortoise Machines With Momentary Contacts - + + - + 1 R 8 S - 1 2 3 4 5 6 7 14 13 12 11 10 9 8 556 - + 15 November 2008