The Angler

Having previously made a project called "The Flitter", I decided to make another project that utilised the same methodology but presented in a different model.

The model in this case is the "The Angler" with a fish on the end of the line over the water, utilising wood, acrylic, brass and 3d printed elements with simple electronically controlled magnetics.

The fish containing a permanent magnet is animated whilst the angler is static holding the rod to which the line and fish are attached. Beneath the pond is housed the electromagnet and hall sensor with the electronics that in conjunction with the magnet in the fish influences movement due to the interaction of a pulsed magnetic field.

Due to the use of the same methodolgy some steps will be identical between the two projects but for continuity and completeness each can be viewed independently.

Final dimensions: 95(W) x 165(H) x 150(L) mm

Supply: 5V5 maximum / ~170mA when active.

3D Printer Filament Green and Black or colours to suit personal taste.

Wooden plank 95(W) x 17(H) x 150(L) mm

Enamelled Copper Wire (ECW), 16AWG/1.29(dia) mm

Enamelled Copper Wire 35AWG/0.15(dia) mm

Machine Screws countersunk M3 x 25mm - Qty 2

Self tapping screws M2 x 8mm - Qty 10

Neodymium magnet cylindrical 5(dia) x 8.5 mm

Hookup Wire 30AWG 1/0.2mm (multiple colours to aid connection identification)

Acrylic Disc 3.5in/89mm diameter

Acrylic panel black: 95(W) x 5(H) x 150(L) mm

Brass tube 6.5 (OD) x 6.1(ID) x 0.2(WT) mm

Brass tube 6 (OD) x 5(ID) x 0.5(WT) mm

Brass Sheet 0.5 mm thickness

Wooden dowel: 6(dia) mm

Hall effect (omnipolar) switch

Transistor ZTX751 PNP

Transistor BS270 NFET

Resistor 1k2 - Qty 2

Capacitor 100nF

USB-C Breakout board

Masking Tape

Coloured paper/thin card of a suitable colour blue and/or green.

Clear Laquer

Strip Board

Right angle pin headers

Rolling barrel swivel #10 - Qty 2

Non slip feet - Qty 4

May prove more cost effective to buy a range of values rather than individual values unless you already have them available. Some components may also have a MOL greater than the quantity specified in the component list.

No affiliation to any of the suppliers, feel free to obtain the supplies from your preferred supplier if applicatble.

Links valid at the time of publication.

Tools

3D Printer

Saw

Needle files

Sanding paper

Craft knife

Soldering Iron

Solder

Wire cutters

Screwdriver

Combination Square

Pencil

Pencil Sharpener

Marker

Awl

Drill

Drill bit 1mm

Drill bit 1.5mm

Drill bit 2mm

Drill bit 3mm

Countersink Drill bit

Wood Drill bit 10mm

Forstner Drill bit 45mm

Forstner Drill bit 35mm

Long nose pliers

Tacky

Plastic Adhesive

Know your tools and follow the recommended operational procedures and be sure to wear the appropriate PPE.

A simple pendulum is a tether fixed at one end to a point that pivots in one plane and a weight that can be fixed or moveable to adjust the swing period.

This project uses an elastic pendulum which differs from the simple pendulum in the following manner.

1: The pivot point is not fixed in one plane but is free to spin and swing in both the X and Y planes with some small vertical movement in the Z plane.

This is accomplished by attaching the pivot point to a semi rigid wire which will flex (effectively a spring), causing the pendulum to bounce and a rolling barrel swivel to enable spin, all which impacts the swing.

2: A rigid tether is replaced with a flexible thin wire.

This allows the tension [influenced by 1], in the wire to vary which effects the radius of the swing arc.

3: The weight is fixed at the end of this elastic pendulum and in conjunction with 1 & 2 also impacts the swing.

All these continual variations create a chaotic swing which like the typical pendulum would stop if an impulse was not applied to keep it moving.

In this case the impulse is a magnetic pulse which in conjunction with a permanent magnet (fixed at the end of the elastic pendulum), interacts with the magnetic pulse (either attracted a repelled depending in the polarities of the magnetic forces at play).

This impulse is applied when the permanent magnet passes a Hall sensor resulting in the pendulum being pushed or pulled continuing the swing.

The 3D printed elements were designed using BlocksCAD, sliced using Cura 4.5.0 and printed on a Labists ET4.

The elements of the Angler are scaled at 75% of full size creating a figure ~77mm high.

Torso

Legs

Arms x 2

Hat

The following are printed at 100%

Pond Edge: 92(dia) x 6(H) mm

Coil Holder: 41(dia) x 11(H) mm

Coil Former x 2: 26(dia) x 2.5 mm

Print details for torso, legs, arms, hat

Size: 75%

Layer Height: 0.15mm

Infill Density: 100%

Shell, Wall thickness 2mm

Build Adhesion: Skirt

Print details for pond edge, coil former & coil holder

Size: 100%

Layer Height: 0.15mm

Infill Density: 100%

Shell, Wall thickness 2mm

Build Adhesion: Skirt

Some post processing may be required to remove aberrations in the cavities and around the edges in addition to widening the holes* for the screws in the legs.

Use a needle file and/or sanding paper to smooth the edge of the parts.

Any holes in the top of the cap can be filled in with epoxy cement and painted or using a filament pen.

Test fit the acrylic disc into the pond edge ring to ensure it fits.

*The holes need to be marginally smaller than the screw to self tap into the plastic and hold the parts in place. If you only have full or half size drill bits use the smaller size and if necessary use a round needle file to adjust the hole size.

Attach the arms with a suitable adhesive to the angler such that the hands are touching and allow to set.

Fit the cap subject to the tolerances that may simply press fit in place or require adhesive.

The coil is made of ~500 turns of 35AWG wire wound on to the coil former.

Stick the two halves of the coil former together and once stuck together, file off any excess ensuring the centre hole is smooth and clear of aberrations.

Measure a length of ~120mm of wire and tape the opposite of the free end to the outside of the former.

Slide the centre of the former on to a dowel or rod that creates a snug fit to prevent it sliding or spinning (a Sharpie pen works well).

Wrap the wire around the former keeping the coils tights but not so tight at to snap the wire or separate the two halves of the coil former, keep winding until the coil diameter is just short of the coil former diameter. Keeping the coil within the diameter of the former help prevents the windings being scuffed during insertion into the coil holder which may result in shorted windings.

Hold down the tail end of the winding to the side of the coil former with tape and measure a free length of ~120mm and cut the wire.

Apply clear laquer to the windings around the circumference and let it dry.

Carefully remove the tape holding the wire to the side of the coil former.

Tin the ends of the two free wires with a soldering iron.

Motion of the Fish is created by the interaction of the magnetic attached to the body and a pulsed magnetic field generated in the coil when the magnet passes the Hall sensor.

The Hall sensor (will detect a magnetic field of either polarity), in the presence of a magnetic field it will have a low output and a high output in the absence of a magnetic field.

The output is connected to the base of a PNP transistor which is switched off when the sensor output is high and switched on when the sensor output is low.

The PNP transistor is used as an inverter between the sensor and the NFET.

As its required to energise the coil when the sensor detects a suitable magnetic field the gate of the NFET requires a positive voltage. However, in the presence of a magnetic field the sensor output is low. Thus the requirement for the inverter.

The coil is mounted close to the sensor such that when the magnet passes the sensor the coil is switched on.

Assuming the magnet is orientated to be attracted to the coil.

This immediately attracts the magnet towards the coil but in doing so it moves away from the sensor. The deminishing magnetic field to the sensor results in the coil being switched off. The magnet then swings back towards the sensor re-energising the coil and repeating the process.

The circuit is assembled on stripboard measuring 8 x 8 holes and with only one track cut at hole co-ordinates (4, 6).

Make the track cut with a 3mm drill bit.

Assemble the circuit such that the components are mounted horizontally to the board and as low profile as possible.

Fit shorting links followed by the resistors, right angle connectors, capacitors then the transistors.

This assembly flow fits components of increasing vertical height with the lowest profile first which makes soldering easier.

Connections are made to the stripboard via right angle pin headers with the leads soldered to the pins.

Check if any shorts or opens exist were they should not with an DMM prior to the application of power.

Remedy any faults found before applying power.

Solder the free end of the leads from the USB board to the appropriate pins (+V & 0V), on the circuit board and check there are no issues when power is applied. Correct any issues before proceeding.

Solder the connections for the sensor (+V, output & 0V) and the coil (+V and FET drain), to the pins on the circuit board, taking care to ensure that sensor connections are correctly orientated. The coil is not polarised and therefore can be connected either way round.

The board is pressed into the space under the support base, if it will not stay in place apply a dab of flexible glue or a double sided sticky pad, alternatively apply masking tape over the hole above the circuit.

The representation of the fish is made from brass sheet and tubing.

Cut two lengths of each diameter of the tubing to 10mm.

Sharpen the end of a dowel with a pencil sharpener.

Fully slide the 6.5mm tube over the pointed end of the dowel and wrap tape both around the part of the tube furthest from the dowel tip and the dowel this will hold the brass tube in place for the next operation.

With long nose pliers using the non serrated part of the jaws align the edge of the jaws with the angle of the dowel and with the portion of the brass tube in the jaws close the jaws to compress the tube. Repeat the process for the other part of the point.

Now with sharp wire cutters aligned to the angle of the dowel point cut off the flatterned portions. Save these two portions as they will be utilised for the fins.

File the edges of the cuts to remove the sharp edges that form the mouth.

Into the smaller 6mm diameter tube with a hacksaw cut a vertical slot in one end ~1mm deep.

From the brass sheet cut an isosceles triangle ~10(H) x 10(W)mm, flatten the apex of the triangle by filing or cutting.

Slide the magnet into the tube behind the slot, ensure there is a space of 1.5mm between the top of magnet and the tube.

Fit the flattened apex into the slot in the tube and solder in place.

Slide the the larger tube over the smaller tube and at the overlap drill a 1mm hole that passes all the way through and out the other side.

Pass a length of ~1mm tinned copper wire through the hole to pass through a rolling barrel swivel and out the opposite hole bending both ends at right angles to the body of the fish and trim.

Using the two triangular offcuts left over from creating the mouth, orientate them with the point facing the front of the fish and parallel with the body and solder in place.

File and shape the fins and tail as required to round and remove any sharp edges.

The fishing rod is made from a length of 16AWG enamelled copper wire (EWC), shaped to support the fish over the pond.

Cut a length of this wire ~155mm long.

At one end of the wire curl a loop in the wire with long nose pliers whilst fitting a rolling barrel swivel and trim off any excess.

Using ~140mm of 35AWG feed ~10mm of the free end through the free loop in the rolling barrel swivel and twist it aroung the wire. Repeat this with the rolling barrel swivel in the mouth of the fish.

The other end of the support wire sits in the hole in the body of the Angler whilst also resting on the arms.

The tail of the fish should hang just above the surface of the pond.

The base is made from a piece of wood measuring 95(W) x 17(H) x 150(L) mm, this was an offcut although not in perfect condition sanding, filling, staining and orientation in combination with other materials made it presentable for the task.

Decide which will be the upper surface and place this uppermost.

Measure halfway along the width and make a mark using a combination square draw a line that passed through this mark to divide the width in two.

From one end measure in 10mm on this line and make a mark, draw a line at a right angles to this line. On this line at 5mm either side of the centre line make a mark.

Using a 10mm wood drill make a shallow hole ~1mm deep and in the centre of this hole using a 3mm drill make a hole all the way through the wood these are for the feet. Countersink the holes on the back of the piece of wood.

On the front of the piece of wood at the opposite end to the two holes previously drilled measure in along the line 50mm and with a 45mm Forstner drill make a hole in the wood 12mm deep. In the bottom on the hole along the centre line at the point nearest the two 3mm holes for the feet drill a 2mm hole.

With the back surface uppermost.

Measure halfway along the width and make a mark using a combination square draw a line that passed through this mark to divide the width in two.

Make a mark along this line at the same end as the two holes previously drilled at 35mm and with a 35mm Forstner drill make a hole in the wood 12mm deep.

From the 2mm hole at the back of the 45mm hole cut a shallow depression (~2mm deep), along the centre line to the 35mm hole. Wires are run along this depression. The depressions can be cut with a burr in a hand drill or craft knife.

At the centre of the long edge cut a depression to accomodate the USB-C breakout and fix in place with 2 x M2 x 8mm screws.

Cut a shallow depression from this to the 35mm hole to run the supply wires.

At this stage defects can be filled and sanded.

Solder 3 long (~120mm), 30AWG wires to the Hall sensor.

Apply clear laquer to the leads of the sensor to act as insulation and to prevent the leads shorting.

With the Hall sensor correctly orientated with the active area facing uppermost.

Bend the leads down at a right angle close to the body.

Form a second right angle bend to the right in the remaining length.

The sensor should fit into the small recess at the edge with the leads pointing down into the coil holder cavity.

The remaining lead length and the point were the last right angle is formed should extend down and under the coil.

Bend the wire soldered to the leads up across and down the centre hole in the coil holder.

For added protection stick a square of tape over the sensor leads that extend down and under the coil.

Feed the leads of the coil down the centre hole of the coil holder and drop the coil former into the circular recess.

The coil former should sit flush with the top of the coil holder.

Feed the wires down through the centre hole in the coil holder and down through the 2mm hole in the bottom of the wood.

Hold the drive assembly in place with masking tape.

Solder the wires to the appropriate points on the circuit and run the wires in the depression in the wood using the masking tape to hold the wires in place

Solder the supply wires to the USB-C breakout and solder to the appropriate points on the circuit and run the wires in depression in the wood using the masking tape to hold the wires in place.

Test the operation with the fish or magnet on a wire to verify both the coil and sensore are working.

When the coil is acttive you should feel a pull or push on the magnet.

If the sensor is functioning the magnet should noticably swing.

If there are any issues double check the wiring.

Fix the legs of the angler in place with 2 x M3 x 25mm screws.

On the front using the centre line to align with 2 of the screw holes across the diameter on the edge ring for the pond mark the 4 screw holes.

At this stage a suitable stain or paint may be applied to the wood as suits personal taste.

The pond consists of a suitable coloured disc to represent the water, covered with a protective clear acrylic disc held in place with an edge ring.

Choosing a suitable coloured paper and using the acrylic disc as a template cut around the disc and into the paper with a sharp craft blade.

Tape the acrylic disc and the paper disc to the edge ring.

Using the holes in the edge ring as a guide use a 2mm drill bit to make 4 holes through the acrylic disc and through to the paper.

Fit the complete sandwich to the front of the wooden base using the screw holes previously marked with 4 x M2 x 8mm screws.

The back of the wood is covered with an acrylic panel measuring 95(W) x 5(H) x 150(L) mm, this covers, protects and holds the wires and circuit board in place.

With a ruler draw a diagonal line between opposite corners, repeat for the other corners.

Measure 10mm in at each of the corners along the diagonal lines and mark.

At these four corner marks using a 4mm wood drill bit* carefully drill 2mm deep holes.

In the centre of each hole using a 2mm drill bit drill all the way through the acrylic.

*A wood drill bit is used as it has a centre spike that creates a centre hole that can be used as a drill guide.

Secure the base plate to the base with 4 x M2 x 8mm screws.

Non slip feet can be applied to the base to prevent slippage of the model and protect the surface on which it sits.

With the base orientated pond uppermost place the torso over the legs.

Place the rod end without the loop in the hole in the torso and rest the remainder of the rod on the gap between the hands such that the fish hangs over the pond.

Apply the power via the USB lead to activate.

That's all for now until the next project.