Make a Self Level Laser (SLL)

Hello everybody !

Today i am going to show you how I made a self level laser on a cheep!

I had this idea for quite a while but never manage to find some time until now.

If you interested on making one, I would suggest to download all files and read everything before any attempt.

For this first attempt the goal was:

To make a low cost unit.

Easy to make.

Easy to use.

Stand-alone, no micro-controller.

To be portable.

To use an internal battery instead of replacing it when dry.

Capable of long time operation.

Use of common materials as possible.

The use of cross line laser all-in-one.

To be accurate at all times.

Capable to operate when placed on non horizontal surfaces up to 20°

Laser locking position capability.

To be able (unit thus laser) to turn 360º vertically and horizontally using optional equipment.

Diagonal line projection when rotating the unit by hand.

masking
tape

Hot glue gun

Adhesive tape

Super glue

glue stick adhesive

Soldering iron

soldering

Tubular Spanner Socket Wrench tool 5mm

Utility knife

Drill – Rotary tool

Drill bits 3mm, 2.5mm, 1mm

Drill metal cutting disk

Desktop ruler

90 Degree Metal L-Square angle ruler

Engineering Compass

Phillips screwdriver

scissors

Pencil

A PCB board 8cm x 8cm x 3 pieces

A PCB board 5.5cm x 5.5cm x 1 piece

A PCB board disk shaped 6.5cm diameter x 1 piece

A PCB board triangular shaped 3.8cm x 4cm x 4cm x 1 piece (see pictures)

A PCB board small parts x 8 pieces

Washers (M3) x 7 – 12 pieces

Washer (M8) x 1 piece

A screw rod of (M3) 3mm diameter x 500mm x1 piece

Secure nuts for (M3) screws x 15 pieces

Wing nut (M8) x 1 piece

Hex Threaded Male/Female nickel-plated brass Spacer M3 Height 20.00mm internal 8.00mm external 8.00mm x4 pieces

Hex Threaded Male/Female nickel-plated brass Spacer M3 Height 10.00mm internal 10.00mm external 10.00mm x12 pieces

Hex Threaded Male/Female nickel-plated brass Spacer M3 Height 12.00mm internal 10.00mm external 10.00mm x4 pieces

http://www.contact.com.gr/catalog/index.php?cPath=35_69_321&sort=2a&page=1&osCsid=951aeb648d07b20a166a1028937752f4

Hex head (M6) bolt x 10mm long x 1 piece

Hex head (M8) bolt x 25mm long x 2 pieces

Hex head (M8) bolt x 10-15mm long x 1 piece

Phillips (M3) screws x 6mm long x 6 pieces

Phillips (M3) screws x 30mm long x 2 pieces

Square aluminum or steel bar 18mm x 55mm long x 1 piece

A piece of metal of 1-1.5mm thick x 45mm long x 12mm width which must be strong enough and won't bend by hand.

Allen driven grub screws (M4) x 10mm long x 2 pieces

Screw Spike for leathers medium size 10mm x 1 piece

Stainless still wire 0,5 – 1 mm x 50mm long x1 piece

Copper tube 4mm diameter x 20mm long x 2 pieces

Plumbing round rubber 3-5mm thick x 20mm outer dia. x 4-5mm inner dia.

Bubble level white (optional)

A cross line red laser

If you can afford purchase a 10-20mW cross-line laser at 4VDC MAX.

A 18650 3.7V battery

18650 battery case

A 18650 battery USB charger

A 3-pin SPST slide switch or a 8-pin DPDT slide switch. Read the (Slide switch) section.

USB female type A connector

SMD white LED (optional)

SMD 100 Ohm resistor (optional)

About 10cm speakers cable

I have chosen to use a PCB
board as a construction material because it's lightweight, thin, strong enough, fairly cheap, can be cut easily using a utility knife and glue the pieces between them using a soldering iron and soldering again and again if need it.

Of course you can use any kind of material suits you best. It can be wood, metal sheet, plexiglass and so on. In case you are going to use a metal like material which is conductive make sure to insulate the lower M3 spacers or make use of nylon ones because the spacers carry voltage from the battery!

What is presented in pictures is the prototype as a reference but the given dimensions and drawings are slightly different so please stick with the numbers.

For your convenience i have included more than enough pictures anyone can follow.

So, let's get started!

The idea:
Earth's gravity and a freely moving in 2 axes heavy object with a laser attached is what I had in mind.

Because not everything in life is perfect and this is a diy project where things may not be perfect there is a need of alignment. This can be done by using 2 extra weights, those will be 2 x M8 bolts

in 2 axes. One for back and forth and an other one for left and right. By screwing / unscrewing the M8 bolts now we can align the laser in vertical and horizontal position.

It's a piece of square aluminum or steel bar 18mm x 55mm long.

If your choice is the steel then you know from the beginning how hard it is to work. It's heavier as a material and requires heavier adjustment screws (HEX M8 x 25mm) or longer ones which is not suitable in our case.

If you choose aluminum then it's easier to work with and requires (M8-M6) adjustment screws.

I had to purchase a 5 meter aluminum bar and cut only a piece of 55mm long so my next choice was the steel as a material.

To make the laser carrier (bar) i went to a machine shop because i don't have the tools needed.

The total cost was 15 euro which I believe is a fear price.

If you don't have the experience in metal working or the tools it's best to let professionals do their magic as i did because precision is a must here.

Download the files and follow the steps to make the bar.

The project is build around 4 screw rods placed on 4 corners and 4 PCB boards one on top of the other. On each PCB use a utility knife and cut the - copper only - at the corner of each side at 13mm x 13mm making 4 triangular shapes for every PCB. Those triangular traces now are going to be the power lines from the battery eliminating the use of cables.

The lower PCB is where the battery and it's case, the SPST slide switch, the female USB connector and the charger are going to be placed. For your convenience I have include a .BMP image file of the schematic. Print the image on a laser printer and use the iron method to transfer the pattern on the PCB.

Next – upper - is the laser locking mechanism PCB. It's purpose is to lock in place the square bar where the laser is attached for manual rotation and also for transferring the unit in safe.

The next board is used for stability and also this is where the last PCB is going to be placed using 4 3mm Philips screws. At the bottom of the board added a white SMD LED + resistor so everything can be seen even in dark.

Finally the last board – the top one – is the one where the Square aluminum or steel bar is going to be attached. If, for any reason there is a problem with the laser, remove the enclosure top cover and unscrew that board, lift it up and removed it from the unit for further maintenance. Also, on top added a white SMD LED + resistor in case of placing a bubble level on top of the unit. In such case, a hole must be opened at the center top of the enclosure.

Print the .BMP image on a laser printer making sure the dimensions are 8cm x 8cm. Use the iron method to make the PCB. If you are going to use an other method reverse the image.

Drill the holes and place the components. Nothing critical hare except from the polarity so pay attention. Leave 2mm space between the USB connector and the SPST slide switch. Use 2-3mm in thickness copper wire between the PCB and the switch. When you are done soldering all components test the circuit. Attach the battery and plug the USB cable. If the charger works then you are done. Take the glue gun and glue the battery case on D board (see pictures).

Ones you have cut the copper from all corners use a pencil and draw an X from corner to corner. The center of the bottom hole of the bar must be at the center of the X you have already draw. Now you know where the Screw Spike should be. Prepare the C2,C3 & C4 and make the hole for the screw spike's screw. Solder the C4 with the tube but make sure the tube is 1mm longer from each side. Assemble the C2 washer – C4 – washer C3 including the M3 screw rod and the two secure nuts. Make sure there is enough space so the C4 can be rotate freely, >1mm space in total must be enough. Mark the rod and cut it. Solder the C2 & C3 from one side making sure the screw spike sit at the center of the C board. Solder / unsolder the C2,C3 until you are satisfied.

On C board open a hole for M3 screw at 3.3cm measuring from the center of the front side.

Next make the round disk and open a hole at the center for M3 screw. Solder the Stainless still wire (see pictures).

Use your pencil and draw an X from corner to corner. Measure 4cm from each side and draw a cross. Use a utility knife and cut the copper only following the cross. Measure 2cm from each side and draw four lines. Use a drill with a cutting disk and cut where those four lines are (see pictures).

The A board is followed by an other six little pieces of PCB. With pencil draw an X from corner to corner. Measure 22mm from the center like 11cm – 0 – 11cm and draw two lines in parallel. At those two lines place the A2 & A3 and draw an other one line in parallel marking the thickness of the boards. From the set of the last lines measure about 3mm and draw an other 1 line from each side and cut the copper using a utility knife. Continue this procedure with the other four pieces of PCB. When you are done cutting the copper with the knife it's time for soldering.

Place the A2 & A3 on board A making sure they are in parallel and the holes are perfectly aligned for best results. Solder the boards one by one making sure they are 90 degrees from the board A.

Download all files attached, print using a laser printer the PCB layout of the lower (D) board.

Print all files / images, measure and using a utility knife make all PCB by cutting the PCB sheet you have purchased.

Αfter having cut all PCB pieces use sandpaper Nr.: 100 to smooth the edges.

Next measure 13mm x 13mm and using a utility knife cut the copper from all corners of all PCB.

Open M3 holes at all corners making sure the HEX treated spacers are not at the edge of the PCB. Do this procedure at ones placing all boards on top of the other and drill the holes if you believe you won't make all holes at the same place exactly.

Cut the copper tube in 2 pieces of 20mm long, cross them and solder using soldering iron.

Solder all (A) board parts together.

Find a piece of copper or other metallic sheet of 1-1.5mm thick which must be strong enough and won't bend by hand.

You are going to make a U shaped piece. Cut a piece of 1-1.5mm thick x 45mm long x 12mm width. Make a M6 hole at the center, measure 11mm – center – 11mm and bend the ends. From the bended point measure 8mm and open a M3 hole at the bended piece (see pictures).

Place the cross tube you have already make on board (A), pass through the Phillips M3 x 30mm long screws and cut them where needed including the space for the M3 secure nut.

Use M3 bolts in between the tubes and the PCB that way so the tubes can be moved freely with the less space in between them. That’s important!

Pass the plumbing round rubber through the M6 screw, then pass the U shaped piece of metal and screw on top of the square aluminum or steel bar.

All boards are connected with spacers starting from the lower level using M3 secure nuts – enclosure - 10mm spacers – board D – 20mm spacers – board C - 10mm spacers + screw rod + 10mm spacers – board B - 12mm spacers – enclosure's top cover - M3 secure nuts.

One of the best solutions connecting the laser with the (A) board is the use of thin ultra flexible multi strand wire, one like that:

In some very good quality headphones manufacturers make use of that wire because of there characteristics in flexibility / strength and frequency response. In our case the flexibility is what we are looking for.

An other solution is the use of one or two wires from a good quality multi strand speaker cable.

The disadvantage using the last method is that the wires might got cut in time. Also, same Ohm resistance is present because they are very thin wires but on my measurements with the laser as it came with it's own cables show that draws 14.7mA at 4VDC instead of 14mA at 4VDC using the hair wire from the speaker cable. So 0.7mA are not critical for the laser's operation.

Remove the protective cover from the laser and unsolder the wires. Make sure to remember the polarity. Take a speaker cable and remove the insulator. Take two pieces of thin wire from the cable at about 10cm and solder them to the positive and negative laser poles. Use adhesive tape to cover the laser PCB and the wires about 4cm long making sure they are not contact each other.

Where the adhesive tape ends measure 4cm and cut the rest of the wires. Insert the laser to the square aluminum or steel bar so the optics are outside the bar and tighten the M4 screws to secure the laser. Solder the ends to the (A) board making sure the positive from the laser go to the positive from the battery and they are at the same side. Continue soldering the negative poles.

I am using two SMD white LED with two SMD 100ohm resistors.

I purchase the LED from a local store but there where no specifications so I made my own measurements. Each LED + resistor draws 40mA connected with the hair wires. In total both LED draw 80mA.

One set is for the cabinet so it can be visible at low light.

The other set is for brighten a bubble level at the top of the enclosure again to be visible at low light .

Instead of using a normal AA batteries I have chosen the 18650 Li-Ion protected one. These batteries have some great characteristics. No need for replacement as there are rechargeable, protection agents over-charge / over-discharge / over-load, there are capable of holding their energy for a long time, nominal output voltage of 3.7V+, large capacity and today there are cheep enough for a diy project.

The charger is a cheep and good solution well made and small enough ideal for the project.

The input voltage is between 4-8VDC which means it can operate from a USB computer port or from any 5VDC device like a phone charger.

The output capacity is rated at 1000mA/h or 1A/h MAX.

As you have seen I have chosen the A type female USB 4-pin connector as an input instead of using the connector from the charger itself. There are thee reasons for that. First of, the status LED of the charger must be visible facing the plexiglass faceplate. Second, because the A type USB connector is larger from the micro USB connector therefor it is easier to open the pin holes on the PCB and solder them. And last, as the A type is larger than the micro one, provides more stability when solder the ground pins to PCB.

A simple 3-pin slide SPST ON/OFF switch used here to turn on / off the laser and the two LED.

There is also a second PCB circuit for a DPTD 3 position 8-pin slide switch which can turn only the laser on or the laser and the two LED all together. The positions are: laser & all LED - ON / middle - OFF / laser – ON. Use small pieces of cable to connect the PCB traces with the switch pins one by one. Use 2-2.5mm thick copper wire where the (sw) symbol is on the PCB to lift the switch above the USB connector by soldering the other end of wires to the switch chassis.

Gather all parts and assemble the frame. Test if all parts and boards fits and make any adjustments.

Is made from five one side copper PCB, one piece of 3mm plexiglass, and one HEX M8 screw.

The bolt with the wing nut at the back of the enclosure can be in use with a (L) wall bracket where the lower part can be mounted on a camera tripod.

If the enclosure have the required distance from the lower part of the bracket then it can rotate 360 degrees always with the laser bar in lock position. This way drawing diagonal lines is easy.

The M8 HEX screw of the enclosure must be level with the center point off the laser.

The enclosure is 2mm wider from left, right & back as a protection in case of sort circuit with the laser boards.

Four HEX spacers are screwed at the bottom piece of the enclosure holding the entire laser construction safe and tide and an other two HEX spacers are screwed at the top cover of the enclosure.

The top cover have two nuts at the sides one on the left and an other one on the right. By using force / screwing the M3 Phillips screws from the left & fight panel of the enclosure the plexiglass faceplate will be tighten in place.

The faceplate is from plexiglass. Use the .cdr file to cut the plexiglass on a laser cutter machine.

There are three drawings giving you the dimensions and also showing you how to assemble the enclosure. Although, took all the effort to draw the parts as accurate as possible, please rely on your own measurements when cutting the PCB boards.

If for any reason the pieces of PCB are larger from the specific dimensions when been cut use a drill with a cutting disk and cut the excess PCB. After that use a sandpaper Nr.: 100 to smooth the edges.

Download and print all files.

Of course it will work as it is but a plain PCB box is not the best view, don't you think?

So after you have completed the tests and everything, disassemble the parts and start painting. Cover the corners of board C1, cover C4 and C5 boards and the rod of the enclosure with masking tape. For me two acrylic enamel spay cans, one yellow mat and one black mat gave me the result I was looking for.

Apply at least 3 thin layers of paint from 30cm distance giving the time needed to dry the paint.

Print the labels on a color laser printer or on a photo copier, cut where needed and apply glue using a glue stick. Place the labels on the box using glue stick and spay paint an other 3 thin layers of mat clear varnish to protect the colors & the labels.

Behind the plexiglass you can place a painted sheet of paper as the frontage marking the SPST slide switch functions etc.

Use the one I made if you wish. Download the file, print it and cut where needed.

That's it!

Now that you have apply the paint it's time for the final frame assemble. Here is how it's done step by step.

Searching the web i have found how construction builders building walls and how they make vertical and horizontal lines.

vertical (plumb)

For vertical lines is the Plumb Bob and line.

Plumb Bob is a pointed weight attached to a length of line used to determine a vertical line.

horizontal (level)

For horizontal lines is the Water Level Tube.

Run water into a tube until it is nearly full. Fasten one end in place so that the water level is at the required height, and take the other end to where you need to mark a guide line at the same level. The water levels at each end of the tube will always be at exactly the same height.

In order to align the laser purchase 6 meters or more of clear tube of 1cm or more inner diameter and a lime with Plumb Bob or make your own one.

Take an old pen and add a few drops of ink in a bucket of water then fill the tube.

Place the tube on wall so the ends are vertical for about a meter or more and follow the above procedure.

First of, we need to know if the projected center of the cross-line is horizontal in relation to laser.

Place one end of the tube at the center of the wall so the tube will be 1-1.5 meters high.

Move the other end of the tube as far as it can go and lift the end at the same level with the end placed on the wall. Place the unit on a stable surface and bring the one end of the tube in front of the SLL so part of the laser beam hits where the water level is. Make sure part of the laser beam hits the water level of the wall tube.

Make sure both ends and the SLL are absolutely stable.

Now, adjust the front M8 HEX rod so the laser beam is level with both water ends. That's it.

Second, take the tube and place it on the wall so both ends are as far as they can go and vertical. Level the ends, measure the center of the tube and place the string line with the plumb bob attached on the wall. The string line will give you the absolute vertical (plumb).

Place the unit at the other end of the room and center it with the string line.

Adjust the parallel HEX M8 rod of the bar by screwing / unscrewing until the laser cross line beam is absolutely vertical and horizontal. When done with the alignment add a drop of instant glue at the HEX M8 rods. That's it!

I have made four drawings of that procedure, download all files and see how easy it is.

On laser (lens)

As you try to align the laser by adjusting the M8 bolts be sure also to adjust the cross-line lens at the front of the laser diode.

The project requires patience and precision both on making and aligning it but worth the try. The alignment is perfect and now that I have my own self leveling laser (SLL) I can do lots of diy things at home like hanging kitchen cabinets.

The 5mW cross-line laser diode is quite visible at indoors light but don't expect miracles when the sunlight hits the wall. A 10-20mW laser would be better for that project and I intend to try one. Also the entire unit including the wing nut & washer weighs no more than 500 kg which might seem a lot but remember, this is the first attempt and because it works I want to share it with you all.

The total consumption is no more than 100mA including the laser and the two LED.

If you choose not to include the two LED then the total draw will drop down to 17mA for the laser operation. If you purchase a Li-Ion 18650 battery/2500mA capacity then even with the 100mA of total draw the unit will be capable to operate for many hours.

All necessary images and drawings are in .bmp and .cdr format. Download the (diy self level laser for instructables.zip) compressed file.

So, that was it. Feel free to comment and suggest what ever you think will improve the project.

If you like that project, please vote!