which servos do you use? and which gear?

[mrmaster]

Hi,

obviously servos with 360° rotation are verrry expensive and probably you can control a normal gauge in a B737-800 with a normal servo and the correct gear, but where do you buy this gear? or do you have different approaches to this problem?

All the best, Marc

[fordgt40]

Marc

Here is a link to building a brake pressure gauge using a servo

http://www.737ng.co.uk/djb/brake_pressure_gauge.pdf

The gears can be obtained here or just do a search on the web

http://www.technobotsonline.com/index.php?dispatch=categories.view&category_id=189

David

[mrmaster]

thank you very much! can you tell me how many degrees the hitec hs55 can turn? so that I can buy the adequate gears...

Marc

[737NUT]

Servocity.com they have everything you need to get full movement

[fordgt40]

Marc

From memory (not to be trusted!!) the servo moves around 180deg when used on opencockpits boards. When making the pressure gauge I think I used a 2:1 gear ratio. It is always better to have some movement to spare, especially as these servos get a bit jittery when approaching the full extent of their movement. Of course, the greater the gear ratio then the more chance of the needle appearing jittery. Try it and see

David

[mrmaster]

hi, I can't find the right gears on servocity.com could you give me a direct link?

[yoss]

Hmm 360 deg servos very expencive?

I would not say. as found today on ebay for prices 5-9 $
Even purchassed one to play arround with

regards
Joseph

[wannabeaflyer]

Hmm 360 deg servos very expencive?

I would not say. as found today on ebay for prices 5-9 $
Even purchassed one to play arround with

regards
Joseph

http://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=p5197.m570.l1313&_nkw=360%C2%B0+servo&_sacat=See-All-
just found these becuse ot your tip thanks

[yoss]

How about those?

http://www.ebay.com/itm/ws/eBayISAPI.dll?ViewItem&item=150725202702

Joseph

[737NUT]

You need 48P or better for smooth operation. Beware of cheap servo's!!! They don't center the same or go to the same spot every time. You get what you pay for, cheap servo, inaccurate gauge movement/positioning. You don't need a 360deg or 180deg for that matter.
http://servocity.com/html/48_pitch_plain_bore_gears.html
http://servocity.com/html/48_pitch_press_fit_pinion_gear.html
http://servocity.com/html/pinion_gears.html
http://servocity.com/html/servo_mount_gears.html

Rob

[wannabeaflyer]

:-) Cheers Rob , Thought there had to be a catch somewhere LOL :-) never thought about the return to center issue , good spot and good info for the future when looking to make DIY servo instuments.

[737NUT]

Also, another caveat is the opencockpits servo card is only 8bit :( Need to find a 10bit or preferably 12bit servo control. They have them for R/C stuff, just not us.

Rob

[fordgt40]

I suppose it depends on the degree of accuracy you are expecting on your gauge movement. 8 bits is fine for the gauges on my overhead.

David