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by Procheta Mallik


The ticker-timer is an instrument that uses a constant frequency source (like the 50Hz AC supply) to vibrate a metal arm at a constant rate. This arm then creates dots on a strip of paper (using a carbon sheet) that is run through the instrument. Building it involves creating a structure to hold the vibrating metal arm, the paper strip (ticker tape) and the electrical connections necessary.

    • Scissors and Cutters have functional sharp edges. Contact may result in injury. Always keep blades away from fingers and body. Handle with care.

    • Be careful while handling metal pieces, they may cut the skin if handled improperly.

    • Always be mindful of polarities (+/-) dealing with semiconductor devices. Applying power the wrong way on the amplifier can permanently damage it.

  1. Start with a piece of foam that's 11 cm in length, 8 cm in breadth and 1 cm in thickness.
    • Start with a piece of foam that's 11 cm in length, 8 cm in breadth and 1 cm in thickness.

    • Cut a piece of Aluminium sheet to just over a centimeter lager than the foam on all sides.

    • Cut the corners as directed. These will help fold the metal sheet smoothly over the foam base.

    • Fold the metal sheet over the base, on the two shorter sides of the foam recangle. This will help the sheet warp less during the final folding.

    • Remove the foam from the metal and apply the rubber adhesive to the surface that was in contact with the foam.

    • Then place the foam back and fold the sheet till it covers five sides of the foam base. Carefully shave away any rough edges with sand paper.

    • Now mark out lines to divide the base into four equal halves. These lines can be made with a maker or light scratched in the aluminum sheet itself.

    • Mark a spot about 0.5 to 1 cm blow the base and use a pair of scissors to make a hole just big enough to be threaded by the screw.

    • Make sure that this hole is smooth and free of frayed edges. Make a slightly larger hole on the other side of the foam to allow the screw to be threaded for the bottom.

    • Drive the screw most of the way into the foam, till it emerges out the other side. And apply glue to the screw head to glue it in place.

    • Ensure that protrudes out at least 1 cm and is relatively perpendicular with the base. Then wait 5-10 mins for all the glue to set before continuing.

    • Make a 3 cm slit in the base about 0.5 cm from one long edge of the base.

    • Cut a large ice cream stick in to a section that's about 6 cm long.

    • Fill the slit with glue and push the section you cut into the foam base. Make sure the stick is secure and perpendicular to the base.

    • Cut the remaining part of the stick into three or four sections, each 1 cm in length.

    • Glue the pieces of the ice cream stick in a stack, to form a spacer about the size of the solenoid's frame.

    • Once the glue has dried, sand the edges of the spacer as will as the faces, to ensure even adhesion to the solenoid.

    • Apply glue to the head of the pin as well as the head of the solenoid.

    • Then glue the pieces together ensuring that the pin is centered on the solenoid.

    • When the glue has dried, sand one face of the solenoid frame, to roughen it up a bit. Now apply glue to this face.

    • Join the spacer and solenoid together and let the glue dry for five minutes.

    • Now its time to stick the finished ticker assembly to the frame. Carefully Glue the spacer onto the ice-cream stick post.The spacing of the needle from the frame is crucial and should be at between 4 - 7 mm.

      • This spacing affects the operating frequency of the finished timer. This is because we are changing the available travel length.

    • Once the solenoid in place and the glue has set. Cut off any excess of the post above the solenoid frame.

    • With the amplifier, USB port and some wires at hand. Start by soldering power wires to the amplifier, these will be connected to the pins marked VBUS (+) and GND (-) on the USB port. The wires should be at least 8-10 cm long.

    • Attach two more wires to the audio input section of the board. This section will have L, I and R markings, they indicate left , ground and right respectively. Attach the wires to the I and R pins.

    • Attach the solenoid's wires to the right output section of the board (OUT R). The polarity isn't crucial so it can be ignored. Additionally, this connection can also be made once the board is mounted.

    • Cut out a piece of paper to a little bigger than the amplifier board.

    • Glue this piece to the back of the board. And cut off the excess paper except at the bottom edge where the wire are.

    • Stick an additional strip of paper across the power and input section to protect and reinforce the wires.

    • Now glue the board to the back of the post, just above the base. A metal piece can be pasted behind the post first for additional strength. But doing so is optional.

    • Make sure all connections are secure and correct. You should have two free wire ends for signal input. Both the USB board and solenoid should be connected to the amplifier.

    • Cut two pieces of foam the size of the USB port.

    • Sandwich the port in between the pieces.

    • Now carefully fasten a binder clip over the whole assembly to secure the port. Make sure that the port accessible.

    • Remove the arms of the clip.

    • Make two holes in the base as will as the foam underneath for the wire to go through.

    • Make a knot out of the wire and string it though the hole so that it is blocked by the knot. And make another knot at the other end as well.

    • The three wire of an audio jack are left, right and a common ground. The Ground can be identified by is grey or black colour.

    • Solder the right and ground wires of the jack to the right and ground of the amplifier.

    • Glue the USB port to the base and reinforce the joint with a foam spacer.

    • Cut an ice-cream stick into two 3.5 cm pieces.

    • And four 1 cm pieces.

    • Stick two of the 1 cm pieces at the ends of the 3.5 cm pieces. This will leave a space of ~1.5 cm for the paper tape.

    • Stick both guides at either end of the base. One can use a strip of ticker tape to make sure they are aligned with the needle.

    • Cut a 5 cm square out of carbon paper, and fold into a smaller square to find its center.

    • Once folded cut the corner that corresponds to the center of the larger square. Cut along an arc along the other opposite side.

    • You should have a more or less circular disk of carbon with a hole in the center.

    • Place the disk of paper on screw holder and make sure it slips under the solenoid needle. The ticker timer is now finished.

    • To ensure proper function the paper needs to be relatively friction free and the disc must rotate when a strip is pulled through the machine.

    • Attach the power cable to the ticker timer, and have it set for 50 or 100 Hz (sawtooth). This can be done either with a smartphone or computer as a signal source.

    • Once this is done, push one end of the strip through one of the slots on the timer. Then, pass it under the carbon paper and out the slot on the opposite side.

    • Adjust the amplitude (volume) of the signal source until the strip has dots imprinted on it.

    • If dots aren't being made on paper, the amplitude (volume) of the input waveform isn't high enough or the frequency is too high.

    • If, instead of a dots, you get lines or very tightly spaced dots, the amplitude of the input waveform is too high or the frequency is too low.

Finish Line

Kailash NR

Member since: 05/02/2017

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