About: A retired electronics engineer -motorola. delveing into new craft ideas and contest entries.

INTRODUCTION- This instructable is a fun music instrument  for Kids and can be made in two nights. It  cab be learned in one hour.Kids can learn to play from a musical score also.


Using standard off the shelf parts and some basics from my other published  similar instruments  the device can be made by any one able to drill , saw, and paint.
     An earlier Instructable worth seeing is [rotating vari-pitch ukulele, dated Aug.22, 2011 by Mistic]
The one  string is a high-tech.polymer stretchable cord or string found in any arts and crafts section of stores.
Notes are generated by plucking  the string as it is stretched.

Step 2: Tools and Materials

Tools- Holes a drilled with a hand held drill or dremel type  drill. The largest hole will be about 0.26 diameter drill. and smallest .076 drill.
A small dremel ]r] saw can be used to cut out the sound hole in the top. Be careful it cuts rapidly.
Knife- to cut out the center hole in the pulley cover.{dwg. item 2a.]
The Pulley  is ready made or can be made from a bottle cap.If  a bottle cap it needs sides.
Fishing cord line spools make fine pulleys.Use 2.0 to 2.5 in. dia sizes.Drill  is a .14 dia. drill bit. for the pulley axle.
The item 19 is a piece of fish cord of nylon about 13 in. long doubled to be about 6 in long.Attach to the stretch string and the slider Item 11.
Material-See list-20 materials. Items refer to the drawing.The list explains the types, size and use.
Glue- Use a strong glue. I prefer E6000 . Fumes are less noxious but  ventilation is needed. Cure is about 2 hours.
Slider- used to stretch the string should be of a good hard wood or pine of a fine grain . Plastic could be used also.
Liners for the  Item 5 and 10 through hole can be soda plastic straws.To fit inside of  .26 dia holes drilled  in the wood..
Crimps-  To crimp attach the nylon to the slider and to the stretch cord ends and bridge no. one.Use jewlery crimps.
Tuner screw- 5/8 hook-eye screw.Steel with collar.Close the round end with a pliers.

Step 3: Assembly

The assembly is in various parts.
a- resonator box- I used a unfinished jewel or cigar box from Micheals store. It was about 3.00 I did a sanding and laquer finish job on it.The paint was water polymer on the sides.  The lid was removed initially and then later glued shut.
The resonator hole can be cut with a dremel saw. The wood mount for the pulley was then glued in place. Later a hole was drilled with a .14 drill as shown. .50 in. from the end of the box.
b- The pulley was made of a plastic medicine bottle cap with sides made of stiff  sheet plastic cut out  .2.5 in. diam. Ahole was then drilled in the bottom of the cap thru the plastic end  discs. Disc material can be any thickness in range of .01 to.032 ..A fishing cord spool is the best.
c- Mount the finished spool on the wood base with 6-32 screw and washers.  The top two nuts are tightened to each other  as a lock  .
To get to these nuts cut out about a 1 in. diameter out of  the top disc. of the cap.
d- Slider is mounted by removing the long  rod and then re-inserting it into the slider and Item 10. It should slide easily on the .25 dia. rod. Use a ..26 dia drill on the slider. The slider also will have a .075 drill  in it to mount the end of the Nylon leader.
e-Tuner ..drill .095 drill hole and screw the tuner into it all way in.
f- Guide holes  Item 5 and 10 will have a piece of soda straw in the .25 di. holes. for lowering friction.
g- Mount the stretch string  on the tuner with crimps. and fish it  thru the guides to the end of guide 4 . Item 4 is the ends that the string is crimped to the doubled nylon.. The nylon is then passed around the pulley  circumference about 6 inches and thru the guide to the slider where it is passed sinto a .074 hole and crimped.
h- Tune- Rotate the screw clockwise till the string sounds as not e G.
The scale as shoe can be a piece of clear plastic under the slider.  Glue a small part of the edge of the plastic.
Tune the device with a casio or piano  by sliding the string till the note sounds. Make a mark at  that location.

Step 4: Play It

This device can be easily played with both hands as follows-  slide the slider  to the right and pluck the string.
It can sound like a hawaiian  guitar. The note locations on   the plastic under the slider  are approximate as the note will drift slightly.
     Most kids can play songs  by ear after a few minutes of sliding and plucking.
Have fun kids..
Vote  in the  Toys  contest.

See picture of the 2 and 3 string devices for older Kids.

Toy Challenge 2

Participated in the
Toy Challenge 2

Be the First to Share


    • Exercise Speed Challenge

      Exercise Speed Challenge
    • Pocket-Sized Speed Challenge

      Pocket-Sized Speed Challenge
    • Super-Size Speed Challenge

      Super-Size Speed Challenge