Best way to make a 'flip up' monitor?

GReeToZ · 01-11-2005, 12:37 PM

Hi,

I'm reinstalling my carputer [Old Install]

i will leave the dvd and actual pc in the same place but want to change my screen. i got fed up removing it everytime so i want to make a flip up screen ala BMW (new ones... we have a BMW Z4 with one and it looks great)

as you see in the pics of my old install i have the screen on the 'clock lcd mount' i removed that mount and it leaves a 'hole' in the dash (will make some pics tomorrow so you will understand)

but my question is whats the best way to make it flip up automaticly by a button or so.. just an electric motor geared down? or any other idea's?

the other problem is that if i just make it flip up it wil be pretty far away for touch (as the axel will be at the back)

so i need ideas to do this

/G

Scouse Monkey · 01-11-2005, 12:45 PM

Use servos and do a search on 555 servo controllers - you can use a couple of these to ahve predefined up and down positions for the servos and the circuits cost pennies to make. Servos are self correcting so will keep the screen in place but i would use some rubber bump stops behind it for extra protection.

To solve the reach problem there are several ways:

1. have the screen face up when closed (not idead for dust etc) but to solve this make a cover that is hinged at the rear and gets pushed up by the screen opening and also provides a sun shade.

2. have the screen on a slide or rack system so as it rotates it slides forward (can link these two motions if you are crafty.

I am using this type of control system for my, dare i say it, motorized screen (which hopefully isn't gonna end up as vapourware)

Scouse Monkey · 01-11-2005, 12:46 PM

Old CD tray mechanisms can also be useful

GReeToZ · 01-11-2005, 12:58 PM

Quote: Originally Posted by Scouse Monkey

Use servos and do a search on 555 servo controllers - you can use a couple of these to ahve predefined up and down positions for the servos and the circuits cost pennies to make. Servos are self correcting so will keep the screen in place but i would use some rubber bump stops behind it for extra protection.

ok i have some experiance with servo's as i build lots of RC cars/boats/planes will look into that. and the rubberstops are a good idea too

Quote: Originally Posted by Scouse Monkey

To solve the reach problem there are several ways:

1. have the screen face up when closed (not idead for dust etc) but to solve this make a cover that is hinged at the rear and gets pushed up by the screen opening and also provides a sun shade.

sounds nice but think facing the screen up is not good without a cover like you say and not sure how the 'cover' you say works any explaination?

Quote: Originally Posted by Scouse Monkey

2. have the screen on a slide or rack system so as it rotates it slides forward (can link these two motions if you are crafty.

this is what i was thinking of, harder to do but i think one of the best ways.

Quote: Originally Posted by Scouse Monkey

I am using this type of control system for my, dare i say it, motorized screen (which hopefully isn't gonna end up as vapourware)

let me know if you have any updates on you're screen i'm gonna look into mine and will post any updates

..

what also mey be a possibility is not making the screen rotate all the way at the back but just off, i think that is what the BMW screen does but i'll take a look tomorrow when there is light again

Scouse Monkey · 01-11-2005, 10:55 PM

Hi again,

1. The cover idea: imagine a cover hinged at the back (like you were thinking for the screen) The screen is loacted under this cover facing upwards hinged at the front. As the screen rotated up it lifts the cover (which has to be longer than the monitor is high due to the whole pythagoras stuff) and when the screen is vertical the cover is angled up.

Hang on better idea: servos are cheap and you will only need a futaba S148 style for the cover so why not have the cover raised by a servo as well: here goes description - try and follow it:

press button or turn PC on etc: open sequence started - cover raised. Tilt switch on cover to detect when started to open then activates the screen tilt (or microswitch at full travel but this would leave a delay). Then when the screen id fully tilted it acitvates a microswitch which then sets the cover motor into the closed position.

When switch is pressed again or power off (eg relay denergises) it does the closed sequence: switches to detect screen is up but cover down so sets cover servo in open setting. Cover now up (hitting cover up switch) sets screen motor to flat position. Switch to detect screen is flat then sets cover servo to closed position.

Note: in open sequence, swtich to detect cover closed could also kill the power to the cover servo but servos don't use much.

Note2: use a decent high power servo for the screen, the servo will keep the screen in position due to the active tracking.

Now for the control bit and fancy stuff:

To control the servos all you need is a 555ic (these cost pennies), a couple of transsitors and a variable resistor per servo. You set the angle by adjusting the resistor so you can set the desired angle through experimentation and then leave the pots. All you have to do for each control step is activate a new pot setting or change control circuit (which ever is easier). I suggest a double pole switch or relay for open/closed settings activating a compeltely different system and then have the closed system turn its own power off when closed (ie when the screen and cover are down). The open circuit can then bypass this power kill when turned on.

You will also be able to manually adjust the tilt of the screen by having a little dial to help get rid of glare.

If you have any Q's about any of this just ask as it is hard to explain and i am currently designing a far more comlicated in-dash system. Threre are programmable circuits out there to do this but they cost a bit of money and do not offer the full control i want. The switching circuits are gonna be messy though.

2. the siding rack system is awkward and can lead to wobble

3. i have seent he Z4 system before but i think you need a deap dash etc to do it.

Thereis another way to control servos using jsut switches and this involves removing the control board - very easy and then you just apply power one way for CW, reverse it for CCW and then apply power to the 3rd wire (i think) to make the servo lock. i have a link somewhere that someone else talking about servos put up but from memory this cost about $17 per servo and does not allow you fine tune the angles using electronics so i swayed away from this. I am jsut sourcing some powerful but cheap servos from China. I am lookig at using 2x8kg/cm servos on the monitor tilt alone as it is easier to use 2 servos as pivots and i will have to hack into the encoders to do this so they both turn the same way when i adjust the tilt but thats simple (actually remove 1 encoder compeltely and wire second servo to the 1st but in reverse).

Hope this helps and i a haven't confused you.

Andy

Scouse Monkey · 01-11-2005, 11:03 PM

oh another thing: for a nice fluch closed look your screen would probably have to cover up and over the dash so the cover can close fully. This would need C shaped brackets. Personally i think this would look ugly as i thinky ou shoudl hide the screen base below the dash level so you could hinge the cover so when it hits the back of the screen it folds like an L on its back. althogh the C brackets would move the screen closer to you. To be honest the whole setup could be made pretty cheap with the main expense being servos (£5-10 each) and a few switches and chips (£5-10 worth) and some scrap metal and hinges/bearings.

GReeToZ · 01-12-2005, 03:55 PM

hmm i read it about 3 times almost understand you hehe,

so the cover is seperatly driven by a servo and the screen is. so far so good. i attached an image how i imagine what you're saying. images say more than a thousand words :P it also shows aprox how much space i have. i cant really cut in the dash as the car is a loan for a year or so and there is limited space under there anyways (vent pipes).

old_lou · 01-12-2005, 04:15 PM

Will this work?

GReeToZ · 01-12-2005, 04:47 PM

no it will be exacly infront of the vents and will look ugly (atleast in my car) thanks for helping with idea's though

might work for somebody else

old_lou · 01-12-2005, 04:52 PM

Put a projector on the back seat and have a pull down screen in the centre of the window/dash

GReeToZ · 01-12-2005, 05:24 PM

Quote: Originally Posted by old_lou

Put a projector on the back seat and have a pull down screen in the centre of the window/dash

thats exactly what a friend of mine said couple of days ago :P, may be cool to do in a show car or something :P but now please ontopic

Scouse Monkey · 01-12-2005, 06:13 PM

Sorry i have been a while replying - my idea was kind of like this:

I am working in servo states i.e. door down, door up, screen down, screen up. These positions are set by the control circuit and can be easilky fine tuned using variable resistors to set the end point.

Each orange flash represents a switch to change the control state.

MASTER SWITCH OPEN STATE:
O1: Door up, screen down
O2: Door up, screen up
O3: Door down, screen open
OPEN!

MASTER SWITCH CLOSED STATE:
C1: Door up, screen up
C2: Door up, screen down
C3: Door down, screen down
CLOSED!

I hope a flowchart and animation are a thousand million words! I have never been the best at expaining things in text (something i need to sort out before writing up my PhD) as i am a true engineer and love to design stuff and hate to explain.

Scouse Monkey · 01-12-2005, 06:16 PM

thats bit quick so can make it slower if you want.

GReeToZ · 01-12-2005, 06:24 PM

Looks like a nice idea!!! but why the hinge? (thats not spelled right?) and damn i'm half English :P) ... and wont the cover hinge in the closed position?

this idea is also nice coz the cover holds the lcd keeps it a bit more solid

its a but quick but looked at it for a minute and its clear

now the other bit, the controller (the servo's are just a matter or mounting them and buying the right ones) i don't have any experience in building my own circuits...

Scouse Monkey · 01-12-2005, 06:37 PM

I put the hinge in so the cover closes flush. Yu don't have to do this, you can set it to stay at any angle but it is better for the servo it goes flat ang just against rubber bump stops as verticle loads will make the cover go up and down and damage the servo - trust me!

Without dimensions of the hole and the cover etc you don't know how mucht he cover is gonna overlap the top of the screen if at all. It would be ok if the cover came down onto the top of the screen (again use some rubber bump stops) but i wasnt sure if you would be happy with the side profile seeing the cover at an angle - thats up to you and i suggest you make a mockup screen and cover etc and see what it looks like.

As for building the circuits they are really easy and consist of only a few components each - even less if you just swtich the potentiomenter at each state change using double pole switches. Will provide some more on this later.

Servos: i have been looking for some nice ball bearing metal geared servos for my screen - much more reliable and stronger. I would normally go Futaba or JR Propo but the high power metal BB ones are £50-100 but I have found a company called GWS in china making some very cheap servos with upto 8kg/cm of torque and 60deg rotation in 0.17 to 0.25 seconds. ie your screen could potentially rise in 0.5 seconds but due to weight will probably be about 1 to 1.5 seconds which would look better. You might be better using 2 servos for the screen but modifying their inner control system (can provide more ont hsi when you are up to speed on how servos work).

Now i just need to get some servos shipped over so i can do some tests. Found a plac eon ebay shipping them over for £9 each + £2 shipping but will contact GWS and see if i can get them direct- they are cheap but should be ok. I can always run them a little over 6V to give them a boost (alwasy used to hardwire servos to the my car batteries when i raced to get faster steering).