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Add LED tool work lights and automatic charge monitors

Posted: Sat Apr 13, 2013 12:33 pm
by burger2227
Many people who enjoy programming also enjoy working on electronics.
I started to add LED work lights to some of my battery operated tools,
but I found that LED lights are not really friendly with 110 volts.
LEDs only need about 3 volts and around 20 milliamps of current.

Normally you would need a large resistor to reduce 110 volts down to 3 volts.
The reduction of 107 volts would also require a power resistor and a lot
of heat or a complicated power supply that might not fit into a tool easily.
The following circuit just uses a .47 uf capacitor rated at 200 volts or more
and a 1000 ohm 1/2 watt resistor to power up to two super bright LEDs:

The circuit LEDs and diodes create about 1.7 volts DC with AC peaks supplying an average of 3 volts.
Each LED would use about 10 ma current on average. About half of a DC circuit.

The lower circuit is an example of obtaining a low regulated voltage from the AC line. The zener diode serves as a
regulator and also provides a path for the negative half cycle current when it conducts in the forward direction.
In this example the output voltage is about 5 volts and will provide over 30 milliamps with about 300 millivolts
of ripple. Use caution when operating any circuits connected directly to the AC line. ... ineled.gif

Note: Always be careful when working with household voltages as they can kill you!

Never touch wiring with the unit open and plugged in! You may have voltages where not expected!

The Black and Decker jigsaw below has a lot of room for a pushbutton switch and the simple power supply components.
Locating the LED light was another matter. Not much room near the front by the blade and metal guard!

I chose to mount the power supply behind the trigger switch to keep the 110 volts in a safe place.

And yes, the 110 volt terminals on the trigger switch are not insulated! Be careful!

The 1N914 diode is required when using just one LED to bypass reverse voltages.
Since the trigger has a variable speed, I just used the 110 volts that came into the trigger
rather than supplying variable speed voltages.

The black wire is hot wire and white is the return line directly from the power cord.
The heavy red wires are 110 volts to motor. They carry high voltages too!

The red and black wires to the right of trigger are the LED wires.

A momentary pushbutton switch can be placed on top, ahead of the trigger
so that a user can press it easily with their thumb when needed:


All open circuit wiring was tape insulated to prevent electrocution later.

Here is the final test of the circuit before I added a momentary pushbutton switch:

The LED lights up the front of the blade work area. I later decided to add another LED
behind the blade by eliminating the diode from the trigger switch circuit
and wiring the second LED in it's place after the pushbutton switch.
The two LEDs should be wired in opposing directions so that both halves of the AC voltage is used.
Normally the long LED leg is the anode or positive lead in DC circuits.

Final product:

QB Capacitive reactance formula determines currents supplied by high voltage AC capacitors:

Code: Select all

'Inductive Reactance = 2*pi*frequency*inductance
'Capacitive Reactance = 1/(2*pi*frequency*capacitance)

  INPUT "Enter AC supply voltage: ", voltage& '= 120
LOOP UNTIL voltage& > 0

ACfreq = 60 ' 50 'in Europe and Asia?
  INPUT "Capacitor farads(1uf = .000001) or microfarads >= .001:"; capacity ' EX:.068 = .000000068
LOOP UNTIL capacity > 0

IF capacity >= .001 THEN capacity = capacity / 1000000

PRINT USING "Capacity = .############ farads"; capacity

Creact& = 1 / (8 * ATN(1) * ACfreq * capacity)

PRINT USING "Reactance = ########,.## ohms"; Creact&
INPUT "Enter other series resistance or hit enter to continue: ", add
RMScurrent = voltage& / (Creact& + add)
current = .9 * RMScurrent * .5 'cap current is 90 degrees off of voltage sync
PRINT USING "Average supply Current = ##.##### amps"; current

LED battery monitor

Posted: Sat Apr 13, 2013 12:36 pm
by burger2227
The following LED circuit can monitor battery voltage and warn you when it gets below a set value:

Savotech Electronics(Note that the site incorrectly has the zener diode upside down)
This circuit uses an LED wired so that it is on when the voltage drops below a certain
voltage or when the voltage is higher using the lower LED. If you only want it to warn
you when a voltage is high or low then just use a normal LED with the appropriate
current limiting resistor. DO NOT forget the resistors!

Contrary to the documentation, the Op Amp pin 6 goes high when the battery voltage matches
or exceeds the Zener value. While it is charging, the 741 sends out a voltage below the battery
voltage so both LED's light up. The lower green LED lights up a bit during the process until it is fully
charged and lights up full.

The Zener Diode should be rated for a voltage about half of the battery voltage which can be any
voltage from 6 volts up. For example a 12 volt battery monitor would require a diode rated near
6 volts (5.6 or 4.7 volts will work). A 6 volt battery works best with a 3.1 volt Zener.

To set the voltage limit, adjust the 100K trimmer or potentiometer. The Op Amp or comparator IC
compares the setting to the voltage on the Zener diode with your setting. To test the circuit just use
another 100K variable resistor to raise or lower the circuit's supply voltage from the
center tap reading supply voltage with a meter.

Monitoring battery charging:


This circuit uses a 2 pin bicolored or bipolar LED wired so that it is red when the voltage drops below a certain
voltage and turns green when the voltage is higher. The LM741 Op Amp
output pin 6 goes high when the voltage is higher and low when the voltage is lower.

The current limiting resistors for 12 volts would be 300 ohms and 150 ohms for 6 volts assuming the
LED draws only 20 milliamps. NOTE: Car batteries are charged up to 13 .8 volts so use 680 ohm then!

The bicolored LED will be both red and green when a tool is charging until it goes full green. The Op Amp
sends a low voltage out of pin 6 until the two inputs match and goes high. It is low enough to allow both LEDs
to conduct at once. The best way to set the charger monitor is to charge up the tool until it is fully
charged and set the green light to come fully on but not too far on.

You can set the LED to come on anywhere down to half voltage when the LED will never light because
of the current limiting resistance.

Monitoring voltages only while charging:

The trimmer or potentiometer can monitor separate voltages with a common ground. This means that
the circuit can be turned on or off by using a switch or by running the circuit only when the charger is
plugged into the tool. The only drain on the battery will be from the 100K resistance of the trimmer resistor.
In fact you can use a larger variable resistance(250 K) to drain even less current. I also advise using multiple
turn trimmers if you don't mind messing with them for better accuracy.

On the Black and Decker chargers there is a diode shrink wrapped near the charger input plug that
rectifies the voltage to charge the tool. Add a diode, (preferably Shottkey to limit voltage drop) before
the rectifier in the tool. The diode in the tool will keep the battery from running the monitor circuit
when the charger is not plugged in. The new diode makes unfiltered DC for the monitor circuit only:


Connect the new diode as shown. I soldered it directly to the back positive lug of the tool charger socket.
You may have to peel a bit of insulation or shrink tubing near the lug to get a good connection. Run a
wire from the cathode to the + monitor circuit. Connect one trimmer end pin to the battery + wire (red)
only and the center tap pin to pin 3 of the LM741 Op Amp. The other end pin goes to negative battery(black).

Don't forget to connect the circuit ground and trimmer ground to the battery ground wire (black) also.
The unfiltered DC may cause both the red and green LEDs to be lit until fully charged when adjusted correctly.

Monitoring battery charging. Rectified + charging voltage is compared to battery voltage
separately so that the LED will only light while charging and not drain the battery.
Also you may want to use a larger value trimmer or add a switch to cut off all drain from the
battery if tool is not used often.


I tested the circuit using a variable power supply as the mock battery and the actual output from the
tool's AC charger rectified with a Shottkey diode at the upper corner of the breadboard. The Op Amp
is an NE 5532 dual comparator so that all input and output comes from and goes to one side.


That's me on the left... :wink:

Putting it in the tool:

This 6 volt Handy Saw (B & D play on words) had a lot of room in the bottom of the handle near
the row of five batteries and it even accommodated the trimmer adjustment. The rubberized handle
even hides the second adjustment hole. That may be necessary when the batteries get old.
My drill's board had to be placed internally and has no easy way to adjust it later.


The green wire goes to the charger input diode which is the only component not on the perforated clad PC board from Radio Shack.
The red wire goes from the trimmer to the battery + terminal. The hidden black common wire goes to the negative battery.

The PC board has two common copper etched rows for the + and - power to go under an IC chip.
The board was hack sawed to size. The saw was busy...
I have made 3 monitoring circuits from one pre-drilled PC board.


I wish that I could find a brighter Red/Green LED. The red above is hard to see, but the green below is easy to see.


Auto shutoff charger

Posted: Thu Jun 06, 2013 3:08 pm
by burger2227
Here is a circuit that monitors the battery voltage and shuts it off when it is charged without using a relay.

The circuit uses an LM338 voltage regulator to control the charging voltage. When the Adjust pin is grounded
by the transistor, the regulator shuts output voltage off. The diode on the regulator output keeps the battery
voltage from being drained off by the transistor and also protects the regulator from reverse currents.
A cheaper BC547 transistor can be substituted for the 2N2222 which cuts off charging voltage
The first thing you must do to add it to a tool is check the input charger voltage. If it is AC, there is a diode
located inside of the tool that rectifies it to DC, Usually one or two diodes will be located between the charging
input and the battery. Place the charging circuit after the diode(s) and connect the + battery to the output of the
voltage regulator! Connect the circuit common to the negative side of the battery also.

Also make sure that your circuit can fit inside of the tool... :roll:

I used two 470 ohm 1/4 watt resistors in parallel for the 240 ohm resistance from the regulator output
to the adjust pin. The 5K variable resistor should be adjusted to the battery voltage + 1/6 extra:

6 volt battery regulator output would need 7 volts
12 volt battery regulator output would be 14 volts

The battery will pull the regulator output voltage lower so set the output voltage using an LED and 1K ohm
resistor load on the cathode side of the output diode before the battery is connected there.

Most kinds of Operational Amplifier should work. Adjust P2 so that the output goes high when the battery
reaches the fully charged voltage. Use a meter to measure the tool voltage when it is fully charged and
set it to that. The Op Amp inverted input, pin 2 requires a reference Zener diode rated at about half of
the battery voltage. For a 12 volt battery it could be any value from 5.6 to 6.1 volts.

To test cutoff, attach green jumper to a variable power supply and increase until LED comes on
Read voltage of power supply and adjust P to cutoff at 1-1/6 the battery voltage or 14 volts for 12.

cutoff voltage = battery + 1/6 battery

Note that the Op Amp is powered by the regulator voltage directly and not the battery. That turns it off when it
is not being charged. The battery voltage is only read on pin 3. P2 should be at least 100K or larger so that the
battery does not discharge quickly through it when it is not being charged. The 2 mega ohm resistor provides
feed back to the Op Amp input to keep it on until the battery voltage drops to a lower voltage. In this case about
1/2 volt less. The 2 M and 47K resistors can be changed to adjust the voltage spread.

A red LED on the Op Amp output indicates when charging is completed. Use a 680 ohm current limiting
resistor for 12 volts. Lower voltage sources require less resistance.

This circuit will allow you to watch something else.

Posted: Fri Jun 07, 2013 2:12 pm
by burger2227
To adjust the charging voltage in the circuit, attach a DC power supply voltage to the LM338 regulator Input.
The prototype uses an input diode which may only be necessary if the tool charger outputs AC voltage.
In the prototype below the meter reads the voltage on the cathode side of the Output diode. The trimmer
on the right adjusts the voltage for 14 volts for a 12 volt battery:
Note that the green wire on the left is temporarily connected to the power supply voltage so that the
Op Amp circuit can work properly. Normally it would be connected to the positive battery bus with
the red wire at the top. If the red LED comes on while setting the regulator voltage, adjust the trimmer
on the left to turn it off! Once the regulator is set, the Op Amp circuit can be set when the battery is
connected later.

After setting the LM338 regulator with the input voltage at 19 volts, the green load LED is on and regulated voltage is 14 volts:
The regulated voltage will stay at 14 volts no matter what the supply voltage is over 15.2 volts.
It will still deliver the same amount of charging current to the battery!

The Op Amp circuit may try to turn off the regulator so you may have to adjust it to turn it back on.
You could also use an IC socket and insert the Op Amp chip later when the battery is also connected.

When the Op Amp is adjusted to turn on, the red LED lights, green LED goes off and the LM338 output is down to 1.25 volts.
The longer yellow jumper is supply voltage to the op amp from the charging power source.
That way the the circuit does not drain the battery at all when it is not being charged. The only
drain comes from the 100K trimmer on pin 3 which determines the battery shut off voltage.

After tests are done, connect the green wire from the high side of the trimmer to the positive battery terminal bus:

On a soldered circuit board it would be a good idea to set the regulator output voltage before adding the op amp.
Use an IC socket so that it can be added later. Just put an LED and 1K resistor on the output as a temporary load.

The Op Amp will need to be adjusted to the battery voltage when it is fully charged. This final adjustment will
have to be done before the tool can be put back together or it will require another adjustable power source.
The hysteresis voltage spread will make it harder to adjust as it will not switch on and off close together.

Posted: Sat Jun 08, 2013 3:58 pm
by burger2227
Here is the circuit board with all of the components except the red LED which will be located elsewhere:
The size of the board area used is about 47mm X 15mm. or 5/8" X 1-7/8". The 8 pin Op Amp only has the
output pin 6 on the right side as the Input voltage(red dot at top) is supplied from a bus that runs down the
center of this type of perforated board from Radio Shack. Mounting the LM338 on the end allows a heat
sink to be added if necessary later on. Two 470 ohm 1/2 watt resistors in paralle lshould absorb any heat
generated when the transistor grounds the regulator. The 5K trimmer on the right adjusts the charge voltage.

A lot of single op amp packages like the LM741 use the same pin out. There should be a notch on top.
The trimmer on pin 3 on the left side adjusts the charger cutoff voltage. Pin 2 reads the Zener voltage.

Posted: Sun Jun 09, 2013 2:11 pm
by burger2227
If only one LED indicator is desired, adding a 100 uf capacitor in parallel with the Zener diode will cause the
red LED to flash momentarily when charger power is first applied.
If another LED indicates power, the capacitor need not be added. I added it because otherwise a user
may have no other indication that the charger is powered up. A larger value will keep it lit longer
if you have the space for it. A cheaper BC547 transistor can be substituted for the 2N2222

Here is the final hard wired circuit with the 100 uf startup capacitor added.
Yellow wire goes to charging input socket AFTER the diode in the tool if the charger is AC. Add a diode when necessary.
Black wire goes to common which should also be black in most tools. Only one common connection should be required.
Blue wire goes to the indicator LED anode(long leg). A current resistor should also be in series connected to common.
Red wire is connected to the + battery. The regulator voltage output can also be read before connecting to battery
Green wire is normally connected to the battery with the red wire. It can also be wired to the input voltage
when testing the cutoff circuit without a battery.

To set the LM338 Output voltage: With volt meter on red and black and input to yellow, adjust the
5K trimmer to 1 + 1/6 battery voltage. Once set, the output voltage on the red wire should not vary.
The rectified charging voltage coming in to the regulator will normally be much higher than battery voltage.
The charger current should remain the same as the current the charger delivered previously.

To set the battery Cutoff voltage, connect the yellow wire to the input voltage and connect the
red and green wires to the positive battery. Adjust as necessary to the fully charged battery voltage.
When the red LED turns on, adjust the trimmer back down a half turn on a 25 turn trimmer. This may take
several adjustments to work properly!

Re: Add tool LED work lights and automatic charge monitors

Posted: Sat Jan 18, 2014 8:01 pm
by burger2227
I bought a Rockwell Sonicrafter tool as refurbished on Ebay. The first tool they sent me did not vibrate at all so I took it apart:
The body has 4 Phillips screws and the front assembly has 4 star bits with center security pins to thwart invaders.
The front cover comes off with a bit of prying. The front assembly slides off of the motor by twisting it as you pull.
The front LED light can be also be unsecured from the front piece as it just snaps onto a square pin.

The motor drives a wheel with a round bearing that is slightly offset so that it strikes one side of a fork and then the other:

The tool only vibrated when the tool was twisted in one direction while sanding:
The fork on the right is broken off with the broken piece to the right side. The fork cavity was filled with red grease.

Rockwell sent me a second tool complete with another 2 12 volt lifetime batteries, another charger, and all the sanding
and cutting tools. If the batteries ever fail, I can send them back for a free replacement! Might be a while now that I own four!

This is a GREAT TOOL! It cuts, plunge cuts and sands with very little movement of the blades. You cannot pop a balloon
with the cutting blades, but it goes through wood like butter. All cutting or sanding material falls below the work area
and it is not blown around like regular saws would. There is even an attachment for a vacuum cleaner hose to clean
up as you work. I cut off small brass screws with the wood blade and it went through them quickly and didn't mess up
the threads! The Sonicrafter has 6 speed settings for working with different materials.

Re: Add tool LED work lights and automatic charge monitors

Posted: Tue Jan 21, 2014 10:44 am
by burger2227
Here's a handy Black and Decker cordless screwdriver I found that just plugs into a wall outlet with folding AC prongs:
It requires two different size star security bits (orange bit pack in BG) to remove 5 screws and a U clamp that
secures the nose piece containing the planetary gear reduction. It pulls out from the bottom after one screw
and a small plastic retainer are removed. (clamp is partially shown on left in picture below)

I found that it seemed to have a lot of torque for its size so I wanted to see what powered it:
Two AA size batteries deliver just 2.4 volts when fully charged. So far the charge has lasted for 6 months at least!

There looks like enough room to replace the batteries with rechargeable AA and even use a regular battery holder.

The large charging capacitor is labeled 105 J which converts to 1 uF from 1,000,000 pico Farads like this:

Code: Select all

                           Units                      mF   uF   nF   pF
                      10 + 5 X 0's = 1,000,000 pF or .000, 001, 000, 000 Farads or 1 micro Farad
So the charging current is limited to about 40 ma by the capacitor alone. The circuit board is under the batteries
so I cannot see what else is there without unsoldering the batteries. I know that the AC is rectified there too.
If I ever have to replace the batteries, I may add a charge indicator LED as it does not have one.
There is no place to put a work light unless I added some kind of mounting further back from the bits.

A micro switch disables the motor when the prongs are fully extended and the center slide bar is fully to the left(see arrows):
The micro switch (bottom red arrow) with square white button disconnects the common ground for the motor.

The forward and reverse control switch is an odd configuration that just reverses the polarity when one side is pressed.
The swithc direction must be set first with the opposite arrow indicating the OTHER screwing direction, not the
one you are currently using. There is a lock at the nose that can be turned to lock the bit. It does not stop the motor
from trying to turn if you press the power switch button however. No room for wiring up front!

Re: Add tool LED work lights and automatic charge monitors

Posted: Thu Jan 23, 2014 12:27 am
by burger2227
Bought a coupla of LED fans for my computer and bench power supply. Today I did my Dell:
I had a 3 inch round hole saw I once used to put ventilation holes in my desk, but it took a bit of luck to drill the hole correctly.
I had to trim out the curved piece first so that the saw would fit between the smile and the power button. Can't move that!

I needed to cut a hole into the case for the fan wiring so I got a chance to try out my new Sonicrafter on steel:
The metal cutting blade is kind of narrow compared to the wood blade, but it cut through with little effort. I just had to
move the tool back and forth to get it to plunge cut. It should make cutting holes for switches in cabinets a breeze!

Here's the finished product:

Here it is at night. Pretty bright. All it needs now is bigger eyes...
It was so bright that I decided to vent some light down into the USB area up front. That is kinda hard to see on the floor.
I may cut some more light vents and maybe even add some blinking LED eyes. It is smiling cause it no longer says Dell.
I drilled the starter hole through the name plate.

Re: Add LED work lights and automatic charge monitors to too

Posted: Thu Jan 23, 2014 11:12 am
by burger2227
I decided to put the Dell emblem back on the fan as a guard to keep toes out of the fan:
To make the fan guard, I just used the clear plastic packaging and cut out a cross. Taped it to the front panel
with the mask removed and sandwiched the guard with the mask. You can barely see it!
I cut out the cross with the bends on each side to stiffen the guard and cutoff the excess. Push in and it pushes back.

The Antec fan comes with an adapter so it can be plugged into the motherboard 3 pin jack or just the temperature wire:
The power adapter can be plugged into a power supply male or female plug. That's what I used as I kept all other fans.
Although the fan power wires are red and black, the connector connects the red fan wire to the yellow power wire.

The Antec fan also has a 3 speed switch to adjust the fan speed wired to a short lead.

For whatever reason, Dell chose to block most of the air flow with a vertical hard drive mount:
I laid it down to get better air flow and light up the interior better. The hard drive case was blocking most of those holes.

Re: Add LED work lights and automatic charge monitors to too

Posted: Sun Jan 26, 2014 12:23 pm
by burger2227
Moving the hard drive must have created problems with the PC's sound. It became scratchy and intermittent!

I had the same problem a while back and had to fix the DMA settings. Do the following:
1) Go to Control Panel\Performance and Maintenance\System\Hardware tab to Device Manager button.
2) Find IDE ATA/ATAPI controllers and click it to drop down the Primary and Secondary IDE channels
3) Right click the Primary Channel and select Properties from the menu. In advanced settings tab it should have DMA if available
selected with the current DMA status below. Do NOT select PIO only!

If the hard drive status says PIO, the only thing you can do to reset it is Uninstall it! Right click the
Primary Channel again and select Uninstall. It will ask to reboot immediately so allow that too.

This may sound harsh, but the computer will reboot and re-install the drive hopefully with DMA access.
After it re-installs the drive, it may want to reboot again so let it reboot and check the Primary Channel status again.

The same procedure can be done with the Secondary Channels that hold the CD and DVD drives.

Re: Add LED work lights and automatic charge monitors to too

Posted: Sat Feb 01, 2014 12:57 pm
by burger2227
Bought a Scotch Thermal Laminator 902 so that I might not have to iron PC boards when transferring circuit traces to copper:
Printed circuit boards can go right through! After 5 or ten passes, the board was up to 120 degrees.

Here is the laminator with the cover removed. The circuit board plug has to be removed on the left
The entire roller and heater assembly lifts out if something gets jammed. The roller motor on the right is 120 volt and only turns CCW.
The rollers start turning as soon as the unit is turned on. Same with the heater, but you have to wait until the blue LED says Ready.

The control circuit board looks pretty simple. Just a pair of 600 volt triacs, a heatsink and a 250 volt capacitor:
The capacitor says 225K which converts to 2.2 uf or 2,200,000 pf. Another cap power supply for what? What's the silver crystal resonator for?

A lot of stuff on the back apparently! The capacitor voltage is rectified and set to 5 volts with U2, a 78L05 voltage regulator.
It doesn't use a lot as the 78L05 is only rated for 100 ma current.

The release lever on the right side can disengage the motor from the rollers when something gets jammed, but it
can also be used to stop a circuit board until it gets hotter perhaps. Pulling things out of the unit was not very easy!

Re: Add LED work lights and automatic charge monitors to too

Posted: Wed Feb 12, 2014 7:40 pm
by burger2227
Bought a Dremel Work Station for drilling PC boards with my rotary tool:
I figure it might also come in handy as a third hand as the holder can also hold it sideways for grinding.

While putting it together I noticed a lot of play in the mounting cup area where you stick the tool nose:
The large bolt was loose so I tightened it up with a 13 mm socket on a ratchet. Now the tool only moves down
when I push on the lever. Those cavities next to the bolt look great for LED work lights too! Hmmm...

My B&D MTX3S rotary tool screws right on to the mounting nut in the cup, but I had to turn it sideways for the cord boot:
The grey shaft lock can be flipped up in the cup opening and the orange power switch can be slid up and down
with a little effort. The tool also uses a Dremel keyless chuck that allows use of drill bits and different size accessories.

Re: Add LED work lights and automatic charge monitors to too

Posted: Thu Feb 13, 2014 6:52 pm
by burger2227
I added two 3 mm white LED's today. Here is what the work area looks like now in normal room light:
So far I have just wired up the 2 LED's without a battery holder, switch or driver circuit. The cup nut tightening wrench
is holding the assembly down for the picture. My LED tester is driving the circuit for the time being while I wait on a battery holder.

Here are the two LED's mounted in the rear of the cup aiming as far forward as possible:
I used clear speaker wire to run to the battery and driver circuit to be mounted up above
Now I have to get a AAA battery box with a switch that will fit up above.

Here is the work station rotated to work as a grinder. Note how the LED work lights light up the small stone:
It is a lot easier to grind things with the object in your hands than holding the tool in one and the work in the other!
The LED battery pack rotates with the tool holder assembly too. Now I won't have to hold that rotary tool when it
gets hot either. I used to have to put it down when it got too warm. I think I'll leave it there.

Re: Add LED work lights and automatic charge monitors to too

Posted: Mon Feb 24, 2014 1:57 pm
by burger2227
I ran into a small problem with the rotation adjustment lever when I loosened it too far and the nut came off:
I took this picture after I dabbed silicone calking all around the square nut to hold it in place. It is tilted to the left
because it is tightened fully. The main press shaft blocks access to it also when assembled.

Here is a look inside where the rotation lock nut is on the upper left and the up and down lock nut is on the right:
I added silicone to both sides of the square nut in the slot on the right to keep the nut in place instead of falling out.
Testing both by removing the bolts completely had mixed results. The rotation lock nut was still hard to re-thread.

I am also preparing a switched AAA battery holder for the LED work lights. It will be held to the unit with Velcro.

Re: Add LED work lights and automatic charge monitors to too

Posted: Tue Feb 25, 2014 1:45 pm
by burger2227
Finally finished up the Dremel Workstation wiring with the AAA battery box up top(left) held with Velcro:
I was able to fish the clear wire through the back plate and solder the wires, tape them and hide them inside the back.
I had to drill a hole in the side of the battery holder to reroute the wires so they were not in the way of the switch on that side.

A 5252F LED driver chip with a 33 uH coil is supplying 30 ma from one AAA battery to the parallel LED's. Each uses 15 milliamps:

The LED's light up the work piece all the way down when using the press. It is nice to not have to push a drill and try to
stop it after it goes through the work. Inertia causes a lot of drilling errors and injuries!

On another note, I found some new bipolar red/green LED's that are brighter red than the old one I was using on the right:
The fact that all three are lit also tells me that they all use similar voltages. Otherwise the lowest voltage one would light.
The LED on the left is clear and bright while the center one is diffused like the old one on the right. Green looks good on all three.
The sellers from Hong Kong say that they are flashing LED's, but the polarity must be reversed to get them to alternate colors.
The long leg on positive side produces red and positive voltage on short leg produces green while the other leg is common.

I plan to try the middle one on my drill charging status circuit because the red is barely visible across the room.
Hopefully the LED voltage required will not affect the charger monitor circuit's Op Amp performance.

Re: Add LED work lights and automatic charge monitors to too

Posted: Sat Mar 22, 2014 9:34 am
by burger2227
Since I received two Rockwell Sonicrafter tools with all of the accessories, I have 2 vacuum sander attachments:
I decided that I could use one of them to suck up dust from my rotary tool when using the grinder or sanders.

The vacuum tool end needed some metal to hold the tool on the work station at any angle with magnets:
It took a few attempts to create a metal ring out of the ends of tin cans. To drill out the center hole first, I used a
pointed one inch hole saw drill bit and drilled down into the end of the can very slowly. Drilling too fast would destroy
the can end or cause serious injury! After the center opening was done, I put the can into a can opener and used
scissors to cut out the outer circle. I had to cut the outer edge very carefully to get a tight fit in the vacuum tool.

Next I arranged 4 magnets around the work station holder cup bottom using super glue to hold them in place:
The magnet center holes help hold them in place.

Here is the final assembly with the attachment hooked to a vacuum hose. The magnets hold it on pretty well:
Note the Dremel Work Station "crow's nest" that holds all of the rotary tool attachments too.

The vacuum tool end was completely open, limiting the vacuum's suction power so I added a cardboard center ring to it too:
The cover helps increase the suction at the outside edges and keeps dust off of the tool and work area.

I don't know how I endured not having the rotary tool work station so long! It makes projects so much easier!

Re: Add LED work lights and automatic charge monitors to too

Posted: Mon Jun 23, 2014 11:31 am
by burger2227
I had been looking for this screwdriver on sale as it was listed at $50. Found it on Ebay for a lot less:
It even has an LED light and turns screws the direction in which it is turned.

A day later the price had increased exponentially:
The screwdriver turns the direction it is leaned to. Left is CCW loosening and right is CW tightening.

The instructions say that the battery can be removed by simply tearing the cover apart and removing the connector wires:
The battery is a tabbed 18650 3.7 volt lithium ion similar to the one shown on the right. B & D says to remove it when you throw the driver away.
I have a funny feeling that I'm gonna replace that battery some day. Hopefully not for another 10 years!

The large white button on the left activates the driver when pressed. The more the unit is turned to the right or left, the faster it turns.

Note: The cover has a label on the bottom that may void the warranty if not peeled off carefully.

The LED never shines on the bit and the trigger button must be pressed to light it up at all! No way to see anything in the dark:
No matter how gently I pressed the trigger button, the bit would turn when I tried to just turn on the LED to spot the job.

The wall charging unit uses a special 3 pronged plug in the bottom of the gyro driver handle. There is no power or charging indicator.
The unit is supposed to flash the LED when the battery gets low or flash twice when the gyro is reset. Pressing the trigger button quickly
while the unit is laying on a solid surface resets the gyro direction settings if it gets too far out of whack.

Re: Add tool LED work lights and automatic charge monitors

Posted: Sun Dec 14, 2014 12:47 pm
by burger2227
I bought an ice scraper online that was heated. I assumed it would also have a light. Oh how wrong I was!
I found 2 screws in the bottom and 2 more after I slid the handle grip off. It was a simple matter to add a 10 mm LED.

The math for current is simple 14 volts - 3 volts = 11 volt drop / .020 = 550 ohms

At 20 ma current I needed 560 ohms resistance with a 3 volt LED on 14(alternator) volts:" target="_blank
I drilled 2 small holes with a rotary tool for the LED legs and soldered a 470 ohm resistor to the positive anode and 100 ohm one to the cathode side.

The 10 mm LED should give plenty of light now for using it at night or in the early morning and it can also sub as a work light:
The hollow handle has plenty of room for a single battery 5252 chip circuit to run the LED after the heater coil wears out too!

Here is the new blue LED light:

Here is the blue light on a window. Later I put clear silicons calking on the LED legs to block water from getting inside of the handle circuitry.

The heater coil gets quite hot! Hot enough to burn you and it takes a while to cool down after it is turned off! Could burn seat fabrics too!

Re: Add tool LED work lights and automatic charge monitors

Posted: Mon Dec 15, 2014 11:14 am
by burger2227
While I was at it, I found my old ice scraper could use some light too. This time behind the clear tough Plexiglas blade:
As you can see it has been well used over the years. I was surprised I could even pull out the blade.

Removing the blade allowed me to drill 2, 1/4" holes for flat top LED's behind it. The holes came out behind the rubber squeegee on the bottom side:

The circuit uses a tilt switch (similar to a small electrolytic capacitor) that turns on the LED's when the 2 leads are facing down.
Each small tilt switch canister holds a metal conducting powder that completes a circuit when oriented correctly.

I drilled a 1/4" hole through the handle to hold the canister. The two bottom gold leads are shown below the battery holder:
One lead goes to the LED positive anodes and the other goes to the positive 3 volt CR2032 battery. The black wire goes to both LED cathodes from the negative battery.

Once everything was wired correctly, I hot glued the battery holder in place and covered up most of the wiring with clear silicone caulking:
Time will tell how the battery holds up! I just have to remember to keep it laying upside down...

Or with this kind of battery holder, a simple slotted square of cardboard or clear waterproof packaging can be used to cut off power:
There are also CR2032 holders that are completely enclosed and have a small on/off switch available on Ebay.

Just slide it forward when light is needed. The positive battery clip keeps the power cover from turning and falling off:
I painted the clear packaging with permanent red magic marker to make it stand out. It could also eliminate the need for the tilt switch.