Indash Retractable Keyboard - in progress

**shotgunefx** · 04-19-2005, 09:49 PM

Some of you might know that I've been working on putting a pc in my car with a digital dash. Being short on excess cash (and time), I've had to put the LCD project on hold for a week or two. But I've got so many things half done, I need to get something solid to satisfy my car modding cravings.

Some I start thinking about getting around to the keyboard. This is what I want.

There's so little room there, so I'm thinking about what I can use that will fit.

My first thought is linear actuators. They're easy to use, and sturdy. I could mount the keyboard to it, mount the actuator inside and I'd almost be done.

Few problems. There usually over $100 (again bad week for this) and they're too strong. I don't need 200+ pounds of force trying to launch my keyboard through my dash if it get's hung up.

I start rummaging through old CD-ROMs. Found one mechanism that would have worked perfectly except for size. I cut and trimmed and cut and trimmed and it almost worked. Due to the 3/4 inch height I have to work with, it would have to be almost behind the hvac controls. So know I need about 11-12 inches of straight back. So that's out.

So I decide to make my own actuator from cheap parts. I get some 3/16 rod, some 10-24 threaded rod, nuts, some spacers and some lego parts I had around (I got a ton of the axles and what not for playing with electronics. I think I'm the only person who got their first lego set after the age 30.) The motor was a cheap one I got at Radioshack some time ago.

Here's a pic of most of it. The middle threaded rod (which moves the keyboard) doesn't have the coupling in this pic. It looks like crap because I used hot glue for the test runs. But it works, even when barely glue together

The two lego axle holders (or whatever they're called) have two pieces of 3/16 rod epoxed to them. These have #10 spacers on them. These slide back and forth and keep the keyboard level.

There's two other screws holding the lego parts together. The middle rod is 10-24 threaded. I took another spacer and threaded it. This is what the keyboard get's attached to and what actually moves it.

Takes about 2 seconds to extend or retract the keyboard.

So know I'll start threaded the connectors and what not to make the connections permanent. Need to make a motor mount. Then I just have to wire up the brain, trim my radio brackets and hinge the center console and call it a day. I'll probably use a PIC for the controller. Kind of overkill, I know. Not decided on if I'm going to use switches or current detecting to determine end of travel.

I'll post more pics and some vids of it in action when I get more done.

**wizawuza** · 04-19-2005, 09:59 PM

Originally Posted by shotgunefx

Few problems. There usually over $100 (again bad week for this) and they're too strong. I don't need 200+ pounds of force trying to launch my keyboard through my dash if it get's hung up.

I know what you mean

Originally Posted by shotgunefx

I think I'm the only person who got their first lego set after the age 30.

yup

Originally Posted by shotgunefx

I'll post more pics and some vids of it in action when I get more done.

Please do.

So how is the motor connected to the threaded rod exactly?

**shotgunefx** · 04-19-2005, 10:06 PM

Originally Posted by wizawuza

...
So how is the motor connected to the threaded rod exactly?

It's going to be with a set screw, I'm going to get a smaller piece of tubing to reduce the spacer to the motor spindle. But for the tests, I just used hot glue which made me feel pretty damn good about the setup seeing it held. I need to expoy a spacer on the other end of the threaded rod as well to silence it a bit as well. The threads hitting the lego make a bit of noise.

**scott_fx** · 04-19-2005, 10:48 PM

this is awesome! keep us posted

**RS3RS** · 04-20-2005, 02:13 AM

Wow! That's awesome... Keep us updated, when it's done you should try to take a video of it in action if possible... Even if it's just a low-quality webcam or something.

**shotgunefx** · 04-20-2005, 03:44 AM

Originally Posted by RS3RS

Wow! That's awesome... Keep us updated, when it's done you should try to take a video of it in action if possible... Even if it's just a low-quality webcam or something.

Thanks. As far as vids, You can count on it. If I can find my damn taps, I'll probably have it all put together today (minus the brains). So I should have a vid of it running (out of the car) in the next day or two.

**Saab9-5** · 04-20-2005, 04:03 AM

Nice work! An 8-pin PIC would work well with the limit switches. It would be small enough to attach to the side of the motor. Like RS3RS, would love to see a video of it in action.

**shotgunefx** · 04-20-2005, 04:23 AM

Originally Posted by Saab9-5

Nice work! An 8-pin PIC would work well with the limit switches. It would be small enough to attach to the side of the motor. Like RS3RS, would love to see a video of it in action.

Thanks. I'd probably use a 16fxxx just because I have twenty or so of them.

What I'm going to do for the moment is wire it to a 3 pos switch and use some normally closed pushbutton switches for the limits. My main concern right now is to just make sure everything works. Play with fitment, etc. When I get around to actually installing it, I'll figure out how I want to drive it. I'll probably use a L293D as I have some on hand.

**shotgunefx** · 04-20-2005, 04:33 PM

Well I started thinking about how to mount it when I realized something convenient. The mounting holes on the motor are perfectly aligned with Lego axel holder.

As soon as I can find my taps, I'll disassemble the motor and thread the holes with 10-24 threads. Use 2 #10 spacers to fill the gap and use 2 bolts to hold the motor to the mount.

As far as mounting the drive shaft to the threaded rod, I decided to dig around the hardware store next door and quickly found these nylon tapits. (Not sure of their proper name.)

It fit the shaft perfectly so I cut it down and pushed it into the #10 spacer. Nice snug fit so I'll probably go this way instead of trying to make a bushing to reduce it. I may revisit it later if it doesn't hold up in practice. So know I just need to find my tap set and tap and thread some holes and the mechanical will be just about done.

BTW, I believe this is the motor. I bought it quite some time ago and discarded the packaging.
Motor @ Radioshack