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

Intro- Hand held rotating pick or plectrum designed to make a stringed instrument sound like a violin or banjo.Portable device.
         This modified devise can be made in about 20 hours from small motors and a LED flashlight using a variable resistor for speed control.
Ref; Instructable"Pseudo Violin with auto-pick" by Mistic  Feb.22,2012 which is not a portable device but has additional details for construction.
The new device uses a standard 3 cell LED flashlite as a power source and a hand held motor and pick that can be used on any stringed instrument. In this DIY  we used a Mistic invented Harpsichord-Lyre  which was not made into an Instructable yet.


Refer to Picture and numbers of completed unit. Fig .1- of 2.

1- Pick .can be any size but used 1 in. made of old credit-card plastic.Bent tip with fingers.
2-Pick mount- wood dowel with slot ends.1/4 dia. x 3 in. lg. Hack saw the slots 1/4 in. deep.
3-Tube. Plastic ,hard.Holds item 2 loosely. 2 in. lg. Used tube from an old pen.
4-Screw-Height adjustrer from top of instrument. 6-32 machine screw.x1 in. lg.Self tap into wood frame item 5.
5-Frame, base. wood swizzle sticks  and two wood blocks .4x.4x.5 in.Glue to item 3 and  Item 6 ,motor sides.
6-Motor- DC.from old dvd-vcr recorder. Draws 40Milliamps at 4.5 vdc of 3 AAA batteries in flashlite Item 11.[ 1 in, Dia.]
7-End sleeve - Plastic tube slipped over motor- guards connector Item 8. Note- can also use a plastic tape as item 15.
8-Connector- from  the dvd player. to disconnect the cable Item 14.
9-Plastic cover. bend to fit over sides and glued in place on item 5.
Fig 2- Battery supply
10-On-off button. built into the end of the flashlite.
11-Mini-flashlite low cost . with an easy remove LED and slide out 3AAA cell holder. LED is not used here.
12-Negative ground connection.Drilled hole in case used to make attachment.Solder lug  on 6-32 screw.
13--End cap- with a 6-32 screw in end.and and a plus terminal solder lug.  use  6-32 nut.
14-Cable . can be any twin wire cable. Flexible  enough to attach to a belt and about 3 feet long.
15-End wrap. can be plastic
16-Speed control . 500 ohm pot{Radio Shack}.About 3/8 in. dia. and LED indicator lite and 1000 Ohm 1/8W resistor.
TOOLS-Pliers, screwdriver, Hack-saw,40W solder iron and Lowmelt solder (RS).E-6000 glue.Drill-press or hand drill.0.105drill size.


1- Attach a wood dowel to the motor shaft. Glue to end of shaft. This motor had a plastic cog on end so wood dowel lays flat on top of it. Wood dowel to be about 3/4 in longx 1/4 dia. and sloted 1/4 in deep at one end.
2- Slip a piece of plastic from old credit card cut out  into slot and other  end into Item 2 Fig 1. rod. Glue  together.
3- Form Item 5 assembly from two sticks and two pieces of wood.
4- Slipt tube Item 3 over rod  and glue to two bloks as shown.
5-Picks . cut out a piece to look like a v- shaped pick and slide it on to the slot  and glue in.
6-Connection to motor- Solder a cable to motor  terminals. In this case we found a quick connector  on the old dvd machine and used it here for connecting the cable.
7 Slip Item 7 tubing over the connector and glue in place on motor end.Make sure no glue gets inside of the motor.

Flashlite assembly.
Remove the LED assembly from end. slip out the battery holder. Discard the LED assembly.
1-Electrical- Drill a .105 Hole in end of flasjlite case about 1/4 in. from end and install a 6-32 screw, nut and solder lug.{RS}.
2- Electrical Plus side- Drill a hole in item 13 plastic cap from soda bottle.Insert a 6-32 screw x 1 in. lg and a nut. Place into the end of  cse to touch the plus terminal side of the battery pack..Place a solder lug on out side . From here we pre-position a speed control 500 ohm mini-pot   on the case and glue in place. connect the lug to the pot and the pot second [ middle] terminal to solder to  external cable  item 14..
  An indicator LED is used to show the power is on. The resistor 1k ohms  is connected to one trminal of the led adn the other end to the Ground lug. The other end of the led is connected to the to Plus solder lug. Observe polarity here for the LED..Cathode to Neg side  anode to Plus.
3- Connection to Motor- connect the cable to the motor and turn on switch in flashlite. You can rotate motor clock-wise or counter clockwise depending on polarity of the cable into motor. Its your choice.We used clock-wise looking into motor front.

Step 3: PLAY -

To play the pick- See figure.
We used one of our home-made string instruments called a Harpsichord-Lyre..We placed the hand held rotor on top and gently rocked forward till the pick hit the string then  pushed  the  On switch. The Pick plastic rotation was  zero. We turned the pot till the rotor  started to turn. Slow turns  sounded like a mandolin   , high speed turning  sounded like a viola. To get  to another string we gently lift the end and repositioned it on a second string.
Lots of sounds can be produced that one never heard before in this world.

Have fun-