In D&D 3.5, is there a mechanism to resemble the use of a remote-controlled car?

Question

Playing a 6th level halfling rogue in 3.5, and I'd like to replicate a door lock mechanism from a copypasta. The setting is sort of prone to Magic Mart syndrome, so access to 1-4th level spells wouldn't be too difficult; alternatively, I could make something with the profession skill or craft skill or ask the party wizard for assistance.

Here's the copypasta excerpt.

It had a lock, but it was nonfunctional and only accessible from the inside. So in order to secure the door while I was away, I got a remote controlled car, attached it to a string which was secured by a fisheye screw at the top of the door, and tied to a security bar which would drop into the tread of the sliding door, preventing it from being opened.

So when I came home, I would whip out my little remote control, make the RC car run off and lift the bar, then gain access to the apartment. To prevent this system from being discovered, I papered the inside of the sliding door with butcher paper, and I ran a wire outside of the door in an obvious manner, so that the roomie would think that this wire somehow, if tugged correctly, would undo the lock. To my knowledge, all of his attempts to get inside my apartment were by messing with this wire, which was attached to the handle of an antique coffee grinder and a paint can. If you tugged it, you'd get a weird uneven resistance as the handle crank turned and the paint can danced, which added to the illusion that this wire was some secret way of ingress.

I'd like to use this as one of multiple security measures to protect all of "procured" loot that my character keeps in his hut while he's out adventuring. How do I get the effect of issuing commands to make something move without line of sight? Doing something clever with a familiar almost works, but I'm a rogue, and don't have easy access to a familiar. A scroll/wand of floating disk almost seems like an option, but, this line from the SRD, is troublesome.

The disk winks out of existence when the spell duration expires. The disk also winks out if you move beyond range or try to take the disk more than 3 feet away from the surface beneath it. When the disk winks out, whatever it was supporting falls to the surface beneath it.

Almost all of the 3.5 books are available to the players, save for the DMGs and Book of Vile Darkness.

So how do I go about constructing a similar effect using mundane mechanical implementations and low level spells?

Answer 1

Assuming that you cannot afford to (or are morally barred from) renaimating a squirrel and then causing it to possess your door with Haunt Shift (ghostwalk), this can be done with a pair of custom magical items.

Assuming a sufficiently paranoid wall-building setup, we'll ignore an adventurer with an adamantine pickaxe, (as strengthening a door only goes so far with weak walls). To restate the objective, this setup should provide no lock to pick and no door to knock. We'll ignore teleport, dimension door, wind form, etc... We will however presume that there exists no line of sight between the two areas, and that adequate protections have been taken against adventurers with drills. (Remember: have drill -- will travel.)

The door itself should be a nice slab of rock (or better), held shut both by gravity and appropriate latching mechanisms. It's important that it not be a door, barred or otherwise, or all your protections are trivialised by knock. The opening mechanism will be some sort of lockable crank, such that spinning the crank raises or lowers the door. (Feel free to embellish on this part to protect against common threats in your campaign. Make it a threaded rod that must be spun if there are commonly hyper-strong people, etc.

Now, impacting the mechanism itself is trivial. We'll presume the spell "mage hand, greater" (spell compendium) is available for enchanting into a higher-priced hand of the mage. (Nominally 1800 gold, going by hand of the mage's 900 gold cost being part of the spell guidelines for 0th level costs.)

The trick will be originating this spooky action at a distance at a distance. ... Which I haven't figured out how to do at low levels without PrCs or spells that are overwhelmingly expensive. Therefore, some sort of complicated mirror setup will be necessary with a peephole or other equivalent means of gaining line of effect to the mechanism.

Ask your DM about if Phantasmal Thief's "An invisible force, not unlike the product of an unseen servant spell (PH 297), comes into being where you wish." means that it can be cast on the other side of a wall (not having line of effect). If it can, then it's absolutely worthwhile to invest in as a custom magical item.

If you were a psion, Remote Viewing combined with Far Hand would accomplish this, but pricing a magic item that can do that is a discussion that you and your DM have to have. (It's certainly better all around to simply have an item-based unseen servant in your HQ instead.)

Unfortunately, this sort of common technological (and cute and insecure) solution found in fiction translates poorly into a magic rich 3.5 world where most adventurers have means of ignoring a door, however cleverly trapped.

Answer 2

Acquire a homunculus...

The closest thing to an RC car is probably a homunculus (MM 154), with which the creator can communicate telepathically. However, abandoning a homunculus in your lair while you adventure more than 1,500 ft. from it makes it a little nuts:

A homunculus never travels beyond [1,500 ft. from its master] willingly, though it can be removed forcibly. If this occurs, the creature does everything in its power to regain contact with its master.¹

However, while the homunculi from the Eberron Campaign Setting (284-7) and Magic of Eberron (121-5) still possess the telepathic rapport and the dislike for traveling beyond 1,500 ft., their descriptions omit the pregnant warning about them doing "everything in [their] power" to regain contact with the master. Thus judicious use of the skill Use Magic Device, a friend or custom magic item providing the feat Craft Construct (MM 303) (the latter costing about 10,000 to 20,000 gp according to the guidelines in the Arms and Equipment Guide and the former priceless), a 500-gp homunculus creation workshop, 1,250 to over 2,500 gp, and precious, precious time will get you what you want.²

Though that's a lot of effort for a glorified lock.

...Or just train an animal

Instead, then, take a few weeks off for animal training. The dog (MM 271-2) is typical and the cat (MM 270) is extremely dangerous but neither has a price.³ The chicken, goat, pig, and sheep have prices but no statistics. The donkey (MM 272) and mule (MM 276) have prices and statistics, however, but either creature's size may be an issue (the mule is Large, the donkey Medium). See what the DM will allow. Take 2 weeks to use the skill Handle Animal to teach the animal the tricks stay and work. Before you leave, give the animal the stay command, which says that

The animal stays in place, waiting for you to return.

Provide enough supplies to keep the animal alive while you're away, pray it doesn't dehydrate, starve, or eat itself to death, and when you return command it—perhaps by simply yelling through the door or maybe by some special signal—to work, pulling the heavy load that will open the door for you.

Unless the DM reads the stay trick as literally as you and I just did, such a system is probably vulnerable to others' Handle Animal skill checks and a thousand other things that can go wrong, but it has the advantage of possibly costing nothing but time and a cat to engineer.⁴

---

Notes
¹ A highly technical reading of this allows the master to travel more than 1,500 ft. from the homunculus, yet not vice versa. Good luck getting the DM to read the text that the way, though.
² An extremely generous DM may allow, from the Pathfinder supplement Pathfinder Player Companion: Alchemy Manual, the loyalty transfusion (625 gp; 0 lbs.), an alchemical concoction that transfers mastery of a homunculus from one creature to another.
³ A generous DM may allow locating free feral or stray cats, dogs, rats, toads, and other animals with a Gather Information, Knowledge (geography), Knowledge (nature), or Survival skill check.
⁴ If this system involves a mule, kiss goodbye your lair's security deposit.

Answer 3

An amusing, though not fool-proof, method is as follows:

We start with a standard rope trick and a standard unseen servant.

We use the rules from Stronghold Builder's Guidebook regarding enchanting architecture.

We build a solid hut, or a "room" in said hut which is actually nothing but solid material. We will need a fake door (simply carved on the wall realistically, maybe have a little crack with a pocket containing nothing but an itty bitty air elemental tasked with the cold draft effect), and a fake lock mechanism that makes funny noises and feels real to people attempting to pick it - again, carved into the fake door. These carved parts are essential so that knock doesn't work on any part of this. Carve additional interactive doodads onto the surface, maybe add a magic mouth or two so that you can give a password, ring a bell, pull a rope, twist some knobs, and otherwise fiddle with things in a certain order, etc..

Said fake door is architecturally enchanted with the rope trick - this allows the plane of the rope trick to be oriented with the door instead of the ceiling.

The inside of the rope trick is then enchanted using the same architecture rules with a permanent unseen servant that is given the instructions, "when i perform action 'x', put the rope out just enough to open the rope trick." Then fiddle with the lock with your fake key and play with the other doodads while solemnly reciting mystical nonsense and performing amusing dance jigs while surreptitiously performing action 'x' whenever you need to open the "door".

If you want a real 'opening door' effect, and can afford it, use Magnificent Mansion instead.

Also, place a Nystul's effect upon the rope trick or mansion effect specifically, or do it before enchanting the rest so as to disguise the actual door from most magical inspection as well.

And don't forget to put skill points in Bluff.

Finally, use some magical method of recording to capture your roommate's efforts to break in, and sell it for a profit to the Wizards Weekly for world-wide distribution.

Answer 4

You can summon an earth elemental with summon nature's ally ii. You can give it orders if you speak its language (Terran). Your earth elemental can phase through stone to get into your room, and then it can do whatever is necessary to let you in. This solution does not require line-of-sight or line-of-effect to the interior of your room.

Your question asks specifically about how to generate a "remote-controlled car" effect and not about how to have a room that is secure against breakins, so I'll defer that discussion to a separate question. :)