Build a Robotic Arm

 
The robotic arm in the picture is a lot of fun to make and use. It uses a first and third class lever, and has a fun linkage for the grabber. It can grab, pick up, and move to the side. A great first project to warm you up using levers and hydraulics. You can peg the small pieces that hold the long arm (as I have), but it takes very precise drilling, so your best bet is to glue the small cross pieces. Once the glue is set though, drilling and pegging will make this model last forever (maybe longer).

Gather the parts!
 

•  6 – 5 ml syringes
• 4 screw eyes big enough for a 3/16 dowel
• 93 cm of tubing to fit the syringes, - 6 mm outside diameter
• 166 cm of 1 x 1 cm sticks
• base –this can be any size, however, mine is 2 cm thick, 8.8 cm wide x 26 cm long ( an 11” piece of
  1” x 4” wood)
• a small disk about 7.5 cm diameter – you can cut some plywood for this, or use the precut wheels
• 30 cm of 2 cm x 2 cm wood – for the stand – any size close to this is OK though
• 50 cm of dowel - 14 cm more if you are going to peg the small crossbars for the arm

Tubing

You need two kinds of tubing:

• the tubes for the syringes are 1/8” inside, 3/16” outside dimension
• (this is 4 mm inside and 6 mm outside dimension) - and the holder tubes – to go around the dowel and the tubing and hold them in place
• this tubing is 3/16” inside and 1/4” outside dimension, (this is 6 mm inside and 8 mm outside dimension)

the holes will be exactly the same distance apart.

Important! – all 3/16” dowels are not the same! I find that if I use a 3/16” drill bit for the holes, the

dowel is so tight in the hole it will not move. So, I use a 13 /64” drill bit and the dowel is snug so the

piece doesn’t wobble, but is loose enough that it moves in the hole with some friction. You really

should test your dowel in a scrap piece to make sure the fit is correct (snug, but not too snug so it

doesn’t move).

With the 1x1 cm wood cut the following pieces:

Cut the 1 x 1 cm wood and drill the holes
The center of the holes near the ends are 6 mm away from the end.
When you drill holes in pieces the same length, lay them on top of each other and drill, that way

3 - 30 cm pieces – rounded at one end2 - 12.2 cm pieces, round off the ends

2 – 7.5 cm pieces

4 – 6 cm pieces, cut on an angle and sanded on the inside edge

4 - 3.2 cm pieces one has a small hole in the middle (use the smallest bit since it is just for a bit of wire)

1 – 2.5 cm piece – drill a 13/64 hole in the middle

3 – 1.1 cm pieces – drill a 13/64 hole in the middle

You will need