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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

01-11-2005, 10:55 PM	#5
Scouse Monkey MySQL Error Join Date: Mar 2004 Location: Bristol Posts: 13,521	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 __________________ If you want more answers on anything I have posted you can find me at digital-car.co.uk or skiing or diving or doing somthing else fun!