The shooter lane

 

The shooter lane consists several parts:

• The lane itself with the groove to center the ball to keep it aligned with the shooter rod.
• and the shooter lane cover, that stops the ball rolling back. It also has some scale to help the skill shots.
• Sometimes the shooter lane also has a auto shooter, that can launch the ball without used intervention.
• And the shooter rod itself

The amount of power the ball receives from the shooter rod depends on several factors:

• Of course the amount the shooter rod is pulled out.
• The strength of the shooter spring.
• Less obvious is the distance between the ball and the tip of the shooter rod.

You can see in the two picture above that this distance varies. In the left picture the shooter tip protrudes the cover, when on the right it is below the shooter cover ball stop. The playfield in left picture can only be lifted, after the shooter rod is pulled back.

Firepower

I recently played for the first time on a real Firepower pinball. I also took some measurements of the shooter lane dimensions.

The wooden side rails are 14x30mm.  The space between them = width of the shooter lane is 35mm.

The out- lanes are 30mm wide.

Design

Shooter lane

To simplify the creation of the shooter lane groove, I created an special insert for it. The original idea came from here: Swinks design http://www.thingiverse.com/thing:608164 for a shooter lane insert. The design seems to be no longer available on thingiverse. This design was on the top face of the playfield.

The shooter lane insert I designed protrudes through the whole playfield. It is mounded on the back of the playfield with multiple screws. The drawback is that the playfield looses a lot of strength, due to the large hole needed to place the insert. Part of the lost strength is taken over by the insert itself. Let us hope the lost strength is not causing issues.

Top view. The holes for the screw have some extra clearance to allow for a little bulging of the playfield wood, then a screw in screwed in. The top is rounded off, to allow it to be make using a 25mm wood drill.

The bottom of the insert contains holes for both the contactless ball sensor and RGS leds. The Leds allow some animation to be shown during game.

The left hole is for the contactless sensor, and the other ones are for the LEDs. The sensor hole is quite deep, so the sensor is very close to the pin-ball. The LED holes have a conical shape, both to allow simple 3d printing as well as to spread the LED’s light around.

Shooter cover

The shooter cover has two main functions:

• Stop the ball from rolling back, when the shooter is pulled.
• Scale to indicate how far shooter is pulled back.

The shooter covers are normally make from metal, but i designed it in plastic. The risk using plastic is that when the ball falls back that it could crashes quite hard back, and then possible break the plastic. The metal one is better, because that just bends and releases the energy back. So the plastic cover has to be quite strong at the ball side.

For the rest it looks the same as the metal version.

Possible I going to change the round woodscrew holes to oval ones, to allow a bit of adjustment relative to the rubber tip of the shooter rod. The shape is designed to it can be printed with a 3D printer. The shape is designed to it can be printed without support, when standing on the ball side.

 

The front where the ball can be hit is made quite thick. Also shown the extra support at the side to absorb the forces better.

 

Assembly views

Some views how the shooter and cover are aligned together.

The shooter lane insert is mounted below the playfield, and the cover above it.

The ball is positioned at the end of the shooter lane insert, and rest against the shooter cover.

Bottom view

Here is the shooter lane insert and cover projected to the playfield.

 

Other view without the cover.

 

The full view of the playfield.

In a later blog will go into more details how this picture is created. This view is still missing lot of parts, like all the ball guides , pop bumper , slingshots and ball trough. These are still in development.

 

Result

I only have printed the insert at the moment.

Here the top view of the insert.

 

The bottom view. On the left the inductive ball sensor holder. The 3 screw pairs on the right are to hold the small WS2812 RGB LED PCB’s. You can see the honeycomb fill pattern used during 3D printing.

Ball sensor

 

In most pinballs, the ball is detected by switches. In older systems these are leaf switches. In more modern ones they are micro switches. In some systems they are contactless.

Leaf switch	Micro lane switch
Leaf lane switch	lane switches between the lane guides

For contactless ball detection are 3 systems present:

• Optical detection with a infrared diode and sensor. the ball breaks the beam.
• Electronic circuit that detects the ball when it gets close to a coil.
• Magnetic detection

optical detection	coil detection	magnetic detection

 

The sensor

I don’t like mechanics switches and I prefer a contactless approach. Less things to get damaged or break. Also for the switches the playfield need a long and narrow slit, what is difficult to make when making the playfield by hand. 

There are induction sensors available on ebay or aliexpress, that are very cheap. Less as 2 usd shipped! I don’t understand how they make them for this amount.

http://www.aliexpress.com/item/Free-Shipping-10pcs-lot-Original-Gaode-Inductive-Proximity-Sensor-LJ12A3-4-Z-BX-NPN-3-wire/2038864848.html

The biggest drawback of this specific type is the detection distance. For the 12mm version this is 4mm. Therefore the sensor needs to very close to the pinball.

There are other types with larger diameters that have much longer detection distances, but also more expensive. This one has a diameter of 30mm and a detection distance of 25mm. It can therefore be mounted below the playfield and sense through it. Still need to order one in for some testing.

http://www.aliexpress.com/store/product/SE-3025A-Genuine-inductive-proximity-switch-sensor-switch-NPN-3-wire-NO-DC6-36V/808493_1980850614.htm

The other alternative is to design my own induction sensor. Then you can adjust the coil size to what is needed. I did some experiments with a LC oscillator, and this looks feasible. I will design a small PCB with and 8pins AVR processor to do some more test.

I have not finalised what approach I will take. For that need to do some more experiments.

12mm sensor

To test the 12mm sensor I designed a holder for it.

top	bottom

This is screwed in the playfield

To bring the sensor close to the ball, the sensor has to stick through the playfield. A small insert is designed with a thin front to bring the sensor as close as possible to the ball. The problem is that the this front is very thin and thus less strong, and question is if it will be strong enough.

The printed insert feels strong enough.

Now I need to find some time to glue the insert in a piece of plywood and do some testing if it sensitive enough.

I also designed a shooterlane with the sensor. Here the sensor works good, because the ball is located and centered above the the sensor. 

 

More about this part in a later blog.

 

 

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LIGHTS !

 

Yes, a pinball without its lights is no pinball.  Also music is needed , but that is problem for later.

LEDS

The lights I going to use on my fabulous pinball are addressable LEDs. These LEDs are all connected in series to form a long string. Each LED can be individually controlled in intensity and colour.  Per string you only need a single bit to control them. The playfield is likely make out of multiple strings to make routing easier. 

The LEDs I found are already pre-soldered with wires in between them, ready to go. Standard they have 50 LEDS per string, but that number can be reduced or increased as needed. 

This is one LED. They are WS2812  RGB LEDSs.

The PCB is tiny: only 10mm in diameter and most of it is used by components or wire connections. This does not leave much area to fix and hold the PCB, so they have to be held by their wires.

Insert lighting

For the insert lighting I needed some bracket to hold the LED in place.  This is the design I came up with after a couple of tries. The LED wires are clamped between the fingers of the holder.

The line on top is to align the LED with the center of the insert. For the different size of insert the holder is different lengths.

Blue is LED model. Yellow the LED holder.

Here is one LED holder mounted on the rear of a test piece.

 

With a LED inserted into it.

The LED just hangs in the air, and is only hold in place by the wires.

 

Another view.  I have not yet programmed an Arduino, so was not able to control them yet.

 

Playfield lighting

The playfield also needs some lighting. I am not certain if these LEDs are bright enough for this purpose, otherwise just need to place some more.

The LED holder has 2 parts:

• A stem that hold the wires and PCB in place. This sticks through the playfield.
• A optional hood that diffuses the LED light.

Both parts snap together .

 

This shows the cut through of the led holder. Blue is led model. Gray is a piece of the playfield.

 

Bottom view of the light. The hole in the bottom is for an optional melt-nut. This can be used with a washer or small bracket with screw to keep the LED in place. Normally the LED will just be kept in place by the wires compressed in the hole. This holds the LED quite good in place.

 

Top view of the diffusor dome. The real one is much rounder than this very course rendered one

 

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Here the actual dome and holder. The wires are folded around the stem and both are pushed together into the playfield from the top.

Inserts

 

Overview

Inserts , like pins, are available in tens of colours , shapes and patterns.

Some shapes and patterns from a old Williams book:

Some of the inserts for sale at the moment:

 

Design

Because I use RGB LEDs, I don’t need to have coloured  inserts, white opaque is enough. The colour of the led will set the insert colour.  The insert only need to be transparent need to diffuse the LED light, so the insert is evenly bright lighting up.

I did some experiments to try to replicate patterns of inserts in 3d printed inserts, but this is difficult. The ‘transparent’ ABS is not transparent enough after 3d printing, to see the patterns on the bottom side of the insert.

The only pattern that works good enough is a circular pattern. Circular patterns on the bottom do not work, but using a low infill (35% ) circular pattern works quite well. That is because it is close to the surface of the plastic, so it is still visible from the top.

The other insert that works well is the plain and pattern less one.

The diameters of inserts are some imperial diameter. Because I only have metric drills, I changed the diameters to metric. I used the following diameters: for circular inserts 19mm, 25mm, 30mm and 40mm for the arrow.

Here some examples

 

The result

Some inserts just printed on the Mendel90 3d printer. The heated print bed is a bit uneven due to the many layers of glue-stick on it. Occasionally I will smooth the glue with some water when it gets too rough.

For the real prints of the insert that go in the playfield, I will print it on glass coated with ‘slurry’. Slurry is ABS dissolved in acetone. Things printed on slurry get a very smooth bottom. This will make the top surface of the printed insert as smooth as glass.

You can see the patterns on the bottom of the inserts with various patterns.

I glued some inserts in a bit of plywood with normal PVA glue.  This works very well. I could not push the insert out of the wood. I am surprised that the PVA glue does adhere to the ABS plastic so well.  Later on will try epoxy glue too, see how that works..

Here the test board from the bottom. The holes are 25mm the whole depth of the hole, without a ridge like real playfields have. Possible the ridge will hold the insert even better in place. Something to try out too.

The plastic part screwed on the bottom is a LED holder. I will write a blog about that later.

 

I will make some pictures with the inserts lighted up.