You gain skill proficiency with smith's tools and tinker's tools. 

Your armor class increases by one and you have resistance to slashing damage. This bonus applies even if you are wearing other armor. 

The default mode powers the sun gear and you have a base 30 feet speed and no changes to your strength. 

By powering the smaller planetary gears you are slower but can apply more torque. Your speed decreases to 20 but your strength increases by 2. 

By powering the larger ring gear you move faster but have less leverage. Your speed increases to 40 but your strength decreases by two. You can't use this mode if it would reduce your strength to a point lower than your current armor requires. 

It takes a long rest to switch between each mode. 

Your unarmed attack damage is 1d4 + your strength modifier.

You are proficient with your unarmed strikes. Your attack roll is d20 + proficiency modifier + strength modifier. 

You can heal during rests to heal like a normal character by physically bending physical parts to their original shape and the magic that animates you restoring your internal components. 

Proficiency checks with smith's tools and tinkerer's tools can also restore hit points. However, this is a slow solution as it takes an hour for every 5 hit points repaired. The number of hit points repaired is 2 x the skill check results. Missing limbs and/or your head can be reattached in this way. 

A mending spell will stabilize you. 

Fabricate will heal 4d8 + the spell caster's ability modifier. 

Other spells work or don't work for healing as based off the spell description. For example, cure wounds doesn't affect constructs but aura of vitality doesn't have that limitation. 

You are immune to poison and disease damage and the diseased, petrified, poisoned, and sleep conditions.

Constructs do not age, drink, eat, sleep, or breathe. However you do need to be inactive for 4 hours of a long rest to replenish the magical energies that power your body. You remain alert during this period. 

There is a small area in your jaw and throat area so you can fake eating and drinking. But this is just a container that must be later emptied. This will hold 20 cubic inches of solids or 12 ounces of liquid. 

Your lower torso has a 12" high x 12" wide x 6" area storage compartment that can be accessed from the front via a hinge in your sides. It is large enough for a book or some of the artisan tool kits. 

Each thigh has a 12" high x 4" wide x 3" deep area suitable for concealing a dagger or wand size objects. 

Gnomish and common would have been overheard and learned during the impressionable period of your creation. 

You can't discern colors while using your 60' Darkvision. 

"Born" with an innate logic your are more intelligent than most (+1 Intelligence). However , it takes a lot of thought to coordinate all your mechanical components to calculate the various inputs to power your movements (-2 Dexterity).