Introduction: POCKET THIEF

About: Last time in my life that I saw the moon that close to me... I was born in the capital city of a country that no longer exists.... I'm in my own timeline and an Electronic Engineer... Received my first degr...
This is a Cadillac Joule Thief with six features.
  • Fits comfortably into a pocket.
  • It is built of SMT components on a IC socket platform.
  • It can drive different color and size LEDs.
  • It does Suck a Batteryalmost completely Dry
  • It will be used to test different brands of AA battery capacity.
  • Yes, it can be used as a Continuity Tester

Sorry, but this project requires advanced soldering skill to build !

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Step 1: Assembled Thief

Bright Pocket Flash Light
  1. Easy to hold
  2. Pointing toward the iCamera
  3. Aim a narrow beam 10' across the room to see the LCD weather station
  4. Close up of LCD station illuminated by a single LED from 10' across the room
  5. LED lightning a tall Victorian ceiling
  6. Detailed component descriptors


Parts you need
  • Small perforated fiberglass board about 1½"  by 3½"
  • AA Battery clip-set and one AA battery
  • A 10mm clear orange LED 36 cdp
  • A Wire-Wrap Socket and a 16 pin solder Platform
  • Two Slide Switches ( You can skip one,  if you don't intend to measure current )
  • Two electrolytic capacitors 100 uF  6.3 V and 100 uF 10 V.
  • Make a 22 mH inductor from the [73K] by unwinding turns & measuring until 22 mH
  • A maxim MAX1675 High-Eff-Step-Up-Converter
  • An MBRD520 SMT schottky diode
  • Two 1206 SMT 470K and a 220K chip resistors
  • Two 0.1 uF SMT capacitors
  • A 100 ohm 1 watt resistor
  • LED socket made from a dual in line 24 pin receptacle
  • Plastic Polaroid Old fixer wipe holder tube

Equipment you need
  • Low end meter that can measure Inductance
  • If things go wrong, an oscilloscope will be handy
  • A band saw or hack saw
  • A box cutter knife
  • A small drill
  • A small Hot-Glue gun

Information you meed
  • MAX1675 PDF ( provided ) useful if things go wrong

Wiring Consumables
  • # 28 gauge Bare wire and low tin lead temperature solder
  • Teflon or any insulating tubing
  • # 24 gauge Bare wire to slid into tubing
  • # 22 gauge Bare wire

Step 3: Hacking a Shield Out of a Polaroird Tube

Hacking  Old  Stuff

This step takes an old Polaroid film fix swiper tube holder and
modifies it to become the LED Shield.
Make two cuts with a band-saw  or hack-saw as shown.
The first cut you should make is a 1/8" slot.  About 2/3  through the tube, near the bottom end.

The Shield is used to mechanically protect the LED.
And it is placed around the LED socket on both sides of the Perforated Board,
as seen on the last pic

Step 4: Build the Platform SMT Circuit

Tune the Inductor
  1. Mount the inductor to the Platform on pins 1 and 16
  2. Measure the inductance
  3. IF too High unwind a turn and re-measure at ( up to item 2.)
  4. ELSE all done do the next component.

Place and Wire the MAX1675  SMD chip
 Using # 28 gauge bare hookup wire
  1. Glue the MAX 1675 SMD chip a shown, double sticky tape also works
  2. Solder a bare wire to Platform pin 13 and then pin 6 on the SMD chip
  3. Leave enough wire to swing right and connect to Platform pin 10
  4. Solder a bare wire to a 0.1uF capacitor bending the right wire down 
  5. Solder that  wire to Platform pin 5 as an anchor
  6. Solder the left wire to SMD chip pin 4
  7. Solder the top of the 0.1 uF to the wire coming from SMD chip pin 6 wire
  8. Solder a bare wire to Platform pin 14 and SMD chip pin 7
  9. Solder a bare wire to Platform pin 12 and SMD chip pin 5
  10. Solder a bare wire to Platform pin 11 looping to pin 15 then SMD chip pin 8
  11. Solder a bare wire to Platform pin  7 looping  to pin  2 then SMD chip pin 1 leaving a finger wire for a resistor

Wire Diode D1
  • Solder D1 to pin15  green and pin 14 red on the Platform

Wire the 100 uF Capacitors
  1. Solder C2 red band to Platform pins 11 & 12
  2. Solder the other side of C2 to Platform pins 9 & 10
  3. Solder C1 red band to Platform pin 6
  4. Solder the other side of C1 to Platform pins 8

Wire Capacitor C5
  • Solder 0.1 uF capacitor C5 across Platform pin 10 and pin 11

Wire 220K Resistor R7
  • Solder 220K Resistor R7 across Platform pin 7 and pin 8

Wire 470K Resistor R6
 Using # 28 gauge bare hookup wire
  1. Solder one side of the 470K Resistor R6 to Platform pin 15
  2. Solder the other side of Resistor R6 to the bare wire from SMD chip pin 1

Platform Pin to Pin Jumpers
 Using # 22 gauge bare hookup wire
  1. Solder a bare wire across Platform pins 9 & 10
  2. Solder the other end to Platform pin 8 at C1
  3. Solder a bridge across Platform pin 11 & pin 12
  4. Solder a Jumper wire with insulating tubing from Platform pin 6 to pin 1
  5. Solder a Jumper wire with insulating tubing from Platform pin 14 to pin 16

Step 5: Preparing the Shielded LED Socket

LED Socket out of Flat Cable Socket

Find any flat cable socket in your junk box or take it off an old PC cable ( pics 2, 3 & 4 ).
Cut it with a saw to at the 3 pin row and trim it square with a knife.

Solder Hook-Up Wire To Pins

Place the LED connector segment in a clamp and solder a 22 # gauge wire to two pins ( pics 5 & 6 ).
Turn the connector 180º and solder another bare wire ( pic 7 )

Color the Connector

It's a good idea to use a red marker on one side of the connector and another color
on the other side if you have it.

Bend the Wires

Then bend the wires so that the LED  connector will hang over the perforated fiber board
as seen in ( PICS 10, 11, 12 & 13 ).

When the bending is satisfactory, set the connector into the shield and
test slide the perf board into it ( last three pics )

Step 6: Finishing the Wiring

Place the Battery Clips First

First Picture, Note the DATUM Hole is at the bottom left of the Perforated Board.
Place the positive battery clip as shown 8 holes right & 3 up from Datum.
Put the battery against the positive and locate the place for the negative clip.
You may have to use your drill to enlarge the perf board holes where the Clips mount to the board.
Solder # 22 gauge bare wires to hold each batt clip in place.
Before going on, Test if the battery fits well in place.


Attach the slide switches, you may have to drill off center holes.
Solder the power switch to the Plus battery clip left pink line.

Solder the Current-measure-switch to Minus battery clip blue line.


Drop the 100 Ohm resistor at the end of the perf board as shown in ( pic # 1 )
And solder it to the Current-measure-switch aqua line.

LED Socket

Attach the LED socket as shown by sliding into place.
A bit of Hot glue to hold it in place.
Solder the negative LED socket to the 100 ohm resistor green line

DIP IC Socket

Place the 16 pin IC socket into the perf board ( pic # 4 )
And solder the LED socket red side wire red line to pin 11 of the IC socket.
Solder pin 1  of the IC socket to the power switch pink line
and pin 8  of the IC socket  to minus blue line.

Step 7: Turning on the Pocket Thief

Loading the Pocket Thief

Plug the SMD platform into the IC socket with the inductor pointing left.

Plug the LED into its socket making sure of the orientation.
The circuit shows a detail of the LED to help you.

Turn ON the I current by-pass switch and leave it be.

Turn Off the power switch.

Insert the AA Battery (see pic # 3 )

Slide ( Turn ON ) the power switch and you should see the LED
Come On Bright Blue !

You can firmly Hot Glue the shield now.

IF Nothing Happens
  1. Try moving the switches there are 4 combinations
  2. Try reversing the LED
  3. Try a different battery
  4. Double check the under perforated board wiring
  5. Double check the platform for a bent under pin
  6. Double check the SMD wiring
  7. Trace the battery voltage with a meter

Step 8: Continuity Tester

This is the Circuit diagram of the Continuity Tester.

Attach two probe lead wires to the minus and the bottom of the 100 ohm resistor.

Open the current by-pass switch and go test something.

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    12 Discussions


    8 years ago on Introduction

    i somehow got the idea of making my own joule thief IC...
    I like how you made the main part of the circuit detachable


    Reply 8 years ago on Introduction

    Thanks :-)
    Its for a future light project that I want to make using it....



    8 years ago on Step 2

    "They feature a built-in synchronous rectifier, which improves efficiency and reduces size and cost by eliminating the need for an external Schottky diode."
    Is a quote from the MAX1675 website.
    is it possible you could have a go at tweaking this circuit to see if it could be further simplified?
    just wondering


    Reply 8 years ago on Step 2

    Thanks for reading the details.
    Yes.... it works without the extra diode however
    They also say the Schottky diode helps the unit to start at a lower voltage.

    Isn't that the point when sucking energy out of a battery ?



    Reply 8 years ago on Introduction

    It IS transferring electricity from the battery to the LED


    Reply 8 years ago on Introduction

    You are very Kind.

    I'm approaching a just few bits away from where you
    created a healthy serving for my centennial soriee :-D


    8 years ago on Introduction

    Great project. What if you could shrink it into a broach, necklace, or earrings?


    Reply 8 years ago on Introduction

    Thanks for the compliment.
    Some time ago some one made earrings that lit and twinkled.
    Ingeniously the battery was a button cell on the inside of the clasp.



    Reply 8 years ago on Introduction

    Only for a few microseconds, it is not the kind of storage device you seek.
    This thing works like an other jewel thief, it uses a magnetic coil or coils
    to transform voltage and current to suit the LED in the circuit.