Tag Archives: DC Electrical

A Linear Actuator *or* The Magic Door!

Being that things warmed up and I was trying to get some stuff put away in my shop, I decided to tackle the linear actuator and get it in place.

The linear actuator, extended.
The linear actuator, extended.

Now some of you may be pausing (or going to the search engine of your choice) and asking ‘what the heck IS a linear actuator?’  Well, it is a screw/worm gear drive that pushes/pulls a shaft along a straight line, into and out of the housing.  These are the things that move lots of slide-outs on modern RVs and trailers.

But, you might also ask, if you don’t have a slide-out, why would you need a linear actuator?  Well, one of the problems with our bus, when we got it, was that there was no way to lock it.  The emergency doors had handles, but they had no key-locks though, they could be locked with a padlock on the interior handle or by installing a keyed household deadbolt through the door to interfere with the existent deadbolt inside, which is what we did to the back door.   The front door locked like a dream, as it was one of the swing-lever accordion doors.

The front door, with the swing-latch in the closed and locked position.
The front door, with the swing-latch in the closed and locked position.

As you can see, this is really secure.  Even if someone broke the glass to get in, they’d have to reach up and unlatch the handle by the gear shift in order to swing the door in.  You might also note the cloth by the latch – one of the problems with the door is that the latch has worn and it rattles while you drive.

The swing arm in the open position.
The swing arm in the open position.

Anyhow, you might note the long rod that connects the swing arm in the center to the door.   When the swing arm is moved to open the door, the rod gets pulled in and pulls the door accordingly.  In looking at it in the right way, if the swing arm was a static unit, in order for the door to open, the bar would have to shrink, optimally about 13″ to open the front door fully.  It just so worked out that Firgelli Automations sold not only a linear actuator with the motor integral to the unit (rather than mounted alongside), but also a remote kit.

Firgelli 12 Inch Stroke Sleek Rod Linear Actuator – 150 lbs Force


List Price: Price Not Listed
New From: 0 Out of Stock
Used from: Out of Stock

4 Channel Remote Control Systems


List Price: $89.00 USD
New From: $91.00 USD In Stock
Used from: Out of Stock

Now, I chose the higher-powered 12″ model rather than the 14″ one, as I didn’t want to stress the door by pushing it too far, and the bar just wasn’t long enough to take the length of the fully opened 14″ one.  But the high-powered one has a push/pull strength of 150#, and a stopped strength of 300#, which seemed pretty strong as a replacement for the 5/8″ steel bar.

Threaded bar end and the hinge at the door.
Threaded bar end and the hinge at the door.

In looking to replace the bar, I needed to save the threaded end that attached to the hinge at the door, and the collar end that attached to the swing-arm.  These were easily enough cut away with the angle-grinder, and leveled (as best I could).

This is a picture of my 12" linear actuator, open, against the cut bar.
This is a picture of my 12″ linear actuator, open, against the cut bar.

I laid these out against the actuator and things looked pretty good.  But where I had planned to weld right to the actuator, it turned out that the fittings on the actuator were aluminum, so I had to create some pockets of angle-iron that would be the way to attach it.

Parts of angle iron for the connector pockets.
Parts of angle iron for the connector pockets.

These had to be cut down, welded, ground a bit more, welded again, then ended with some flat plate and drilled so that they would attach to the actuator.  As the bar-end of the actuator was not a nice, square piece but rounded as the bar was, and then rounded to allow for a swiveling action that I really didn’t want,  I had to make the pocket that would connect to the threaded rod not only a tight fit, but also longer so that it wouldn’t swivel or flex at all.

The connector cups, fitted and drilled to be attached to the actuator.
The connector cups, fitted and drilled to be attached to the actuator.

So after a little extra work, I had everithing ready to put together.  The connector pockets needed to be painted to keep down rust on the new grinds, and I decided to go with the brass paint, for the fun of it.

Here's the new linear actuator in place!
Here’s the new linear actuator in place!

The linear actuator bar wend in place great, however I discovered that if the round, extendable actuator bar with the screws on it moves and allows you to screw it into the door fitting, you’re actually unscrewing it from the motor and it’s a bad thing ™.  Luckily, the bar screwed right back into the actuator, and all I had to do was detach the other end from the swing arm and then screw the whole bar in and it worked out fine.

The remote, inside the door switch area.  The wires for the linear actuator go out through an existing hole in the bottom.
The remote, inside the door switch area. The wires for the linear actuator go out through an existing hole in the bottom.

I decided to use the space inside the door switch area of the swing arm to mount the remote, which worked well, as it already had a power line and ground screw in place.  The best thing about this placement is that the wires from the actuator don’t hang up on the swing arm when I use that.  With the actuator fully extended, the door operates normally.  With the swing arm locked, it works like this:

True it doesn’t open quite all the way, but it’s enough to get into and out of the bus, and the full extension of the linear actuator closes the door up snug enough that the door handle doesn’t chatter because it’s loose and worn anymore.

Now, all I need to do is get a DPDT swtich to run the door from inside, and it will be perfect.  But for right now, I have a keychain remote door lock for the bus!

Testing out the Backup Camera(s) (Part II, The Testing)

(Continued from Part I)

So with the cameras and the screen, I was ready to test them out. The screen was easy, as it had its own AC adapter.  I was able to just plug it in and it came right on, gave a nice blue screen indicating that it was set for the VGA input, and after 10-15 seconds of finding no signal, it went to sleep.

I could wake it easily by either selecting a new input (VGA->Cam 1->Cam-2->VGA cycle), or by just hitting the power button, but with no input, it just went back to sleep again.

The screen with a real image!
The screen with a real image!

I have a mini-HDMI->VGA adapter for my tablet, but that didn’t work to give a testable signal, so I had to go hook it up to an old XP box.  The booklet manual said that the optimal resolution was 800×400, but the computer’s resolution wouldn’t go down that low.  At the lowest setting though, it was pretty easy to see.

Tiny little icons at higher resolution on the graphics card.
Tiny little icons at higher resolution on the graphics card.

Putting it back up to some 1100×800 dpi (the computer’s regular output setting), the image was still pretty clear, but the text and icons got really small.  I’ll have to play with the setting once I get the bus’ computer up and running.

But with proof positive that the screen was in good shape, I went to checking out the cameras.  The little, cheap camera just had the red and black wires for power, so rigged a plug using a female four-pin power connector from an old computer fan, and hooking it up to an adapter that was meant to power a hard drive. With the VGA connected to the screen, and a button push to cycle camera 1’s input I got … a black screen.

A little clarification.
A little clarification.

At first I checked all my connections, then realized that if I cycled the input again to camera 2, I got a picture. One Sharpie later, I had that system all worked out, and went about trying to get a nice image I could photograph easily, but found that it wasn’t easy to get what I wanted because the picture was, indeed, mirrored (just like I knew it would be but my hands still wanted to turn it the other way).

The little, cheap camera`s eye view.
The little, cheap camera`s eye view.

One of the other issues that people complained about was the guidance lines.  In looking at the view, I don’t see them being very intrusive.  I can, however, see how they form a great fixed reference point for backing up.  For this picture, the camera was at couch height, and the distance to the far wall is ~21 feet.

I hooked the other camera up to the same power source, and put it in a similar placement (just next to the first camera).

The bigger back-up camera's view.
The bigger back-up camera’s view.

The lines are more pronounced on this camera, but they are more colorful.  The back wall here looks closer, but you can see less of the walls, even though the two cameras were at the same distance.

In recognizing this, the cheaper camera has a much greater field of view, but with much more distortion.  At the time, I just noted it, but in thinking about it since then, it seems that this difference will actually help me with placing the cameras on the bus.

But there was another thing to test with the more expensive camera, and that was the IR LEDs.  For that, it was an easy thing, as the photosensor that turns the LEDs on doesn’t need complete darkness – even a good shadow would do it.  So for that, I just held the camera up off the couch (looking at the couch), and lowered it until the LEDs kicked on.

No IR LEDs on ...
No IR LEDs on …
... and with the IR LEDs on.
… and with the IR LEDs on.

The ‘night vision’ works fine, though the bright ‘light’ of the LEDs washes out the colors.  But really, when I’m backing up at night, I think the color of the object I’m getting too close to is less important than if I can see it clearly.

So my plan is now to mount the small, cheap camera up high on the bus (there’s a bevel right above the back dome window and below the clearance lamps that should put it at a great angle), and use it as a regular rear view mirror, displayed on the screen during normal driving operation.  I’ll get a nice view of what traffic is right behind the bus, and a nice wide angle on the sides.  The other camera looks like it will need to be pretty close to the ground for the LEDs to have a good effect, so I’m going to play around with mounting it under or just above the back bumper.  Since I can change between the two views with just a click of the cycling button on the screen, I should be able to get both a ‘big picture’ and then a more detailed view when backing in somewhere.

I’ll post again for on-the bus placement testing and installation …

 

Testing out the Backup Camera(s) (Part I, The Parts)

So, with all the cold weather and lack of being able to work on the bus, I pulled out the backup cameras and screen, to test them out.  I had had these for a while, but they were still in the boxes, and I wasn’t sure how and where I’d be installing things.  I ordered all these from Amazon last winter and just never got around to them.

 

So, here are the parts, all expanded out of their boxes:

NEEWER Waterproof CMOS/CCD Reverse Backup Car Rear View Camera
NEEWER Waterproof CMOS/CCD Reverse Backup Car Rear View Camera

NEEWER Waterproof CMOS/CCD Reverse Backup Car Rear View Camera (Electronics)


List Price: Price Not Listed
New From: 0 Out of Stock
Used from: Out of Stock

Here is a relatively cheap back-up camera that had decent reviews, and I thought I’d give it a try, or keep it as a spare if the other camera ended up not working or burning out too soon.  It attaches by way of a hollow, threaded post through which the wiring goes.  It has a small plug/socket set to connect the camera to the DC power/return and the 25′ long RCA cable (which will be a little short for the bus).

The attachment for the cheaper camera.
The attachment for the cheaper camera.

There had been some complaints about it not being really waterproof, but it looks good to me, given that the lens and body are all nicely molded together, and the back (with the post) is screwed into it with four small screws, meaning that the only place for water to get in is at the back, which you should be sealing up anyhow.

The molded body of the cheaper camera.
The molded body of the cheaper camera.

They included a little pieces of what seems to be a 1/16″~2mm foam tape (which somehow escaped my picture) to put on it, but I’ll use a thin bead of butyl rubber when I go to attach it.


Night Vision Parking Car Rear View Wide Angle LED Reversing CMOS Camera

Night Vision Parking Car Rear View Wide Angle LED Reversing CMOS Camera

BW 3.6mm Wide Angle Car Rear View Reversing Backup Camera with Night Vision (Electronics)


List Price: $10.59 USD
New From: $8.00 USD In Stock
Used from: Out of Stock

This was the ‘fancy’ back-up camera that I opted for.  It’s ‘fancy’ because it has the IR LEDS that kick on when it gets dark enough.  I had figured that this would be the main back-up camera for the bus.

IR augmented camera. 7 IR LEDs and one photocell sensor.
IR augmented camera. 7 IR LEDs and one photocell sensor.

It attaches to the vehicle by the side-flanges, and the wires come off the back.  It has separate plugs for a rather standard ‘+ in’ 12 VDC plug (the red one in the picture) and a female RCA jack for the video.  The camera came with 25′ of RCA cable, but I have a run of 50′ that I’ll use instead.

Like the cheaper camera, the body and lens are all together in one nicely molded piece, with a ‘hatch’ that’s screwed down on the top.  Again, I’m figuring on using some butyl rubber sealant around the seam there to try and keep out water, which I expect to be a bigger deal with this camera, since the opening is up and there’s a bigger hatch.


One of the major complaints in the Amazon reviews about both of these cameras is that the image is backward, and you can’t change it, or that it’s been built wrong.  However, these are really back-up cameras, designed to be installed in a particular way so to give an image that’s going to give the driver a familiar view of a rear-view mirror. And they do that just fine, so I think a lot of the issues in those comments is that people didn’t understand what they were buying.


Lilliput Eby701-np/c/t

Lilliput Eby701-np/c/t

The Lilliput screen is a 7″ touchscreen with a VGA input as well as two RCA inputs and a reverse-sensor that automatically changes the input to a camera’s input when the transmission is shifted into reverse. It had some good reviews as being a reliable and visible screen for vehicle use, able to interface with a vehicle-based computer (which I’m planning on installing).  It runs on 12 VDC, but also came with an AC adapter (which made testing a whole lot easier).

Lilliput screen connections.
Lilliput screen connections.

It also turned out to have TWO RCA inputs (Video 2 is the one activated by the reverse sensor), so I’m likely to install both back-up cameras and have them each on separate channels (more on this in Part II). The cables that came were actually in two parts, perhaps in case one didn’t have an on-board computer.  The first connects to the screen and includes the power jack (black), RCA jacks (yellow), reverse sensor (green wire), an audio input (white), and the screw-on secured connector for the other wire which connects to the VGA jack and a USB connector for the touchscreen.

Armed with these bits (and a 12 VDC power source from a USB IDE hard drive connector), I got into actually testing the system.

(Continued in Part II …)

 

 

 

 

 

Lilliput Eby701-np/c/t (Electronics)


List Price: $119.00 USD
New From: $119.00 USD In Stock
Used from: $99.00 USD In Stock