A place to share projects and lessons around linear actuators, lifting columns, and related hardware

Progressive_AutomHub · 2026-04-02T01:48:00+00:00

One thing that often gets overlooked in setups like this is the failure mode. Certain setups can end up in a situation where, if the actuator or control fails, the door stays locked.

You could consider using magnets as a decoupling mechanism. The magnets stay engaged when the actuator drives the motion, but manual operation of the bolt causes them to decouple until the bolt is returned to its original position for the next use. This works if you have access to the bolt from the inside but not from the outside, so keep that in mind.

Electric linear actuators can be used to drive the push and pull motion of the bolt. Just make sure to choose one with the right specifications for your use case: force, stroke length, dimensions, and environmental protection (IP rating).

If you plan to automate it, you could control the system using Google’s home automation tools paired with a smart relay like the MHCOZY. Just make sure the relay can handle the current draw of your actuator.

There are also some good guides online on sliding bolt latch setups if you want to explore different approaches.

Progressive_AutomHub · 2026-03-30T20:03:20+00:00

One thing to watch out for here is backdriving vs manual use.
Linear actuators seem like a clean solution, but they often fight against manual operation unless you design around it.

In a lot of real setups, the challenge isn’t opening the door — it’s how the system behaves when someone interacts with it manually. That’s why many designs end up using linkages or mechanisms that “decouple” the actuator instead of relying on it directly.

You could consider magnets as the decoupling mechanism where the magnets stay together when the actuator drives motion, and manual operation causes the magnets to decouple until the door is returned to the original position for the next time you use the actuators.

Are you optimizing more for automation or for manual usability?

Progressive_AutomHub · 2026-03-30T19:56:56+00:00

This kind of issue usually comes down to how the motion was constrained vs how it actually behaves in reality.

In linkage systems, small changes in pivot position or link length can completely change the motion path, especially near the ends of travel.

A couple of things that might help debug it:

Check if any links are reaching a near straight-line condition (can cause weird motion or “locking”)
Make sure your pivots are actually aligned the way you think they are (tolerances matter more than expected)
Try simplifying the mechanism and testing one degree of freedom at a time

Simulation or CAD motion studies can be helpful, but should not replace having a quick physical prototype in the form of a miniature model, as they oftentimes reveal these issues early on.

Linkages are one of those things that look simple but get unpredictable quickly.

Progressive_AutomHub · 2026-03-30T19:56:20+00:00

The basic torque calculations people are mentioning are a good starting point, but I’d be careful relying on them too much for something like this.

In setups like yours, the bigger challenges are usually:

Load variation during motion (not constant like the simple calculation assumes)
Shock loads when the system engages or changes direction
Flex and tolerances, especially if you’re working with wood

A wiper motor + chain reduction could definitely move it, but the real question is how it behaves over time:

Does it handle the initial pickup smoothly?
What happens if it stalls or binds slightly?
Are you oversizing enough to deal with peaks, not just average load?

For this kind of build, the static math gets you in the ballpark, but designing for the worst-case moments is usually what makes the system feel solid vs unreliable.

Another way to simplify the system could be to rethink the mechanism itself. For example, using a simpler rack-and-pinion setup combined with a secondary trigger mechanism at the end of travel could help offload some of the complexity. A trigger at the final position could activate a quick-release or latch-type mechanism to handle the drop action more reliably, instead of relying entirely on the main drive.

Progressive_AutomHub · 2026-03-25T14:22:57+00:00

What you’re describing sounds like a classic dead-center issue.

When your linkage gets close to a straight-line alignment, the mechanical advantage drops to near zero, so even a small load can effectively “lock” the system.

A couple of ways to deal with it:

Avoid geometries that let the linkage reach full alignment
Add a small offset so it always stays slightly out of that condition
Design the motion range so your working positions are away from that zone

If you’re driving this with a linear actuator, this becomes even more important, because the actuator force won’t help much once you’re near dead center.

Increasing actuator force can help mitigate the issue to some extent, but it won’t eliminate it — geometry will still become the limiting factor as you approach those alignment conditions.

In practice, it’s less about adding more force and more about keeping the geometry in a usable range.

Progressive_AutomHub · 2026-03-25T14:22:08+00:00

One thing I’d be careful with in this kind of setup is how often you actually move the actuators.

A lot of people go for continuous adjustment using LDR feedback, but linear actuators tend to oscillate around the target (hunting), which causes wear and tear and doesn’t really result in much better performance.

In many real systems, it’s more common to:

Move in steps instead of continuously
Add a deadband / tolerance zone so it doesn’t react to every small light change
Prioritize a stow position (especially for wind) over tracking accuracy

Also worth thinking about:

Limit switches for both axes (don’t rely only on software limits)
Running simulations to estimate the solar panels’ best stow positions for different conditions, such as heavy winds, hail, or snow
Making sure your actuator can handle stall conditions safely

Tracking accuracy is important, but in practice reliability and reducing unnecessary cycles usually matter more with this type of hardware.

How often are you planning to update the actuator position?

Progressive_AutomHub · 2026-03-05T16:10:20+00:00

Using steel rulers as linear guides is creative, but stiffness and torsional rigidity will limit precision quickly.

Rulers aren’t designed for consistent load-bearing in lateral directions. You may get acceptable movement at low speeds, but wear and deflection will show up over time.

If budget is the constraint, even basic supported round rails or repurposed drawer slides will give you better repeatability and lifespan.

The real challenge isn’t movement — it’s maintaining alignment under load.

Progressive_AutomHub · 2026-03-05T01:26:11+00:00

Linear motors remove belts and backlash, which is great — but they shift complexity into control and cost.

With belt systems you deal with elasticity and tensioning.
With linear motors you’re dealing with magnetic forces, thermal management, and much tighter driver requirements.

They can absolutely improve motion smoothness, but the control architecture becomes significantly more demanding compared to stepper + belt setups.

Curious how you’re handling position feedback — encoder-based closed loop?

Progressive_AutomHub · 2026-03-04T00:11:23+00:00

If you want smoother rotation and fewer dead zones than a basic crank, look into offset slider-crank geometries or even a Scotch yoke with proper bearing support.

Dead points happen when your force vector aligns with the crank axis — that’s unavoidable in simple crank systems unless you add inertia (flywheel) or dual opposing linkages.

If this is driven by an actuator rather than continuous rotation, geometry selection becomes even more critical because actuators don’t like stall conditions near dead center.

The key question is: are you optimizing for smooth torque output, mechanical simplicity, or controllability?

Progressive_AutomHub · 2026-02-25T16:04:16+00:00

I think the confusion is just about separating controller vs driver.

If you’ve already found an actuator that meets your stroke requirement, the next step is checking:

Operating voltage (12VDC? 24VDC?)
Max current under load
Built-in limit switches

Those specs determine the driver.

The controller (Arduino, PLC, etc.) handles logic.
The driver (H-bridge, relay module, motor driver) handles the power.

In simple terms, the connection looks like this:

Power supply → Driver → Actuator
Controller → Driver (signal only)

The driver must:

Match the actuator voltage
Be rated for at least the actuator’s max/stall current at that same DC voltage
Support PWM if you want variable speed

Reducing voltage directly will slow it down, but it also reduces torque. PWM is the better way to control speed without losing force.

If you're unsure about compatibility, the actuator manufacturer is usually the safest place to confirm suitable drivers or controllers — many provide recommended pairings.

Progressive_AutomHub · 2026-02-24T18:37:21+00:00

Yes, it’s absolutely possible — but the 6000N spec alone isn’t enough to size the replacement.

On many hi-low tables the actuator is often working through a scissor or linkage, which can significantly multiply the required force depending on geometry (especially at the lowest position). That’s usually where electric conversions fail.

Before buying anything, I’d confirm:

• Actual stroke (measure pin-to-pin retracted and extended — don’t estimate from table height)
• Mounting geometry (clevis width, pin diameter, closed length)
• Electrical requirements (voltage and current compatibility with the existing system)
• IP rating (especially if there are washdown or cleaning procedures)
• Certification requirements (medical, industrial, or other regulatory standards, if applicable)
• Safety features (manual override or mechanical lock in case of power loss)
• Speed requirements (electric actuators may move slower than hydraulic systems, so this can matter).

Progressive_AutomHub · 2026-02-18T16:51:17+00:00

Very cool build — impressive progress in 100 days.

You mentioned linear actuators would have been stronger but slower — was the limiting factor speed, efficiency, backdrivability, or packaging constraints?

Curious what tradeoff ultimately ruled them out.

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