Arduino-servo Useless Machine V2

I have designed a bunch of useless machine this last couple of years and I came up with this one that I believe is very fast and simple to build for whose has: 

• -access to a laser cut machin
• -some knolege on soldering and basic circuits
• -litlle knolege on arduino

Be safe and have fun!

For this box you will need:

• 3mm (1/8in) MDF board cut
• 1 arduino ( I used nano for fitting in the box)
• 1 micro servo (9g or similar) and its screws
• 1 battery pack
• 1 switch (2 positions)
• 6 small self tap screws (2.2x6.5mm)
• 1 3/16x1/2 bolt, 1 washer and 2 nuts
• some wire
• 1 power switch
• something to hold arduino, like a proto-board or in my case a vector board
• some jumpers

Cut a pice of 3mm (1/8') MDF using the file below. The blue lines are used as reference and support for assembling

assemble the box folowing the sequence like the pictures above. Be carreful not gluing the lid at the "hinge connetion"

glue the pices above using the little triangle as reference:

• B + C
• E + D using the line as guide
• A + E

Cut one side of the longest servo horn

use 2.2x6.5mm self tap screws to link the "hod" to arm and servo

I found out that this combination using the fruthest hole at servo horn works best for this mechanism

attach the switch as shown, no matter if the conection is inverted for now, it can be delt at coding part

insert the 3/16x1/2 bolt trough piece B, the washer and piece E

tight up one 3/16 nut in the piece D cavitie - at this point, piece B should be able to spin trough the 3/16 bolt

tight up the the second 3/16 nut in the bolt

You shold test the mechanism for moviment, but do not overload the servo

conect the servo, arduino and others like the chematics above

load the arduino code

I like to disconnect the servo arm from the servo while first run on arduino so I can put the servo at neutral position (90 deg.) This way I garantee the servo arm will be centred

for starting using the arduino, I first set the maxLimitServo and minLimitServo to value 90

#define maxLimitServo 90 //change this value 10 ->170 to adjust travel down
#define minLimitServo 90 //change this value 10 ->170 to adjust travel up

then, I put the servo arm in a way the useless finger will be at the midle position and tight up its screw

after that, I change those limits to 70 110 (min and max) and test the witch berravior.

if the berravior is inverted I change the line:

if (state==HIGH)

to

if (state==LOW)

Then I increese the range until the lid can be fully closed and the switch fully pressed.

tight up the top screws, fix the arduino and the battery pack. That is it, this box should be working

Be safe and have fun

:)