Tiny servos and compatibility to receivers

[Stuart Marsden]

Just looking to build a Dep-Stik Sept15 freeplan. Inspired to make own designs using light equipment. I have discovered that some of the smallest servo plugs are wired differently to JST plugs. Please advise of compliant wiring for say 2 to 3 grams. Servos to use Futaba or Spretrum radio. I have a 4 channel Spectrum receiver as a beginning but am prepared to invest in balanced gear. Please advise use.Potty Flyer

[Denis Watkins]

Yes Stuart, use them, there are conversion leads on eBay and other suppliers, like extension leads, but with jxt and regular receiver plug at other end

[Simon Chaddock]

Stuart

I suppose it depends on just how light you want to be.

using a conversion lead is likely to add virtually as much weight as using a slightly larger servo (say 3.7g) which does have a normal JST connector..

Those very tiny servos with the miniature connectors are intended to be used with super light weight receivers like this.

[Stuart Marsden]

Thanks for this. I suppose I am looking at Parkfly that will fly in large indoors 75 to 100 gram models. Anymore advice gratefully received. Potty Flyer

[Stephen Jones]

Hi Stuart,

Have a look here Indoor Flying i make a lot of indoor flyers you may like the £1.99 Rubber Band plane i converted to Rc using tiny servos and receiver .

i use Frsky

But i have a hack module in my radio ,

But you could use a Futaba compatible receiver ,

Indoor models need to be as light as possible or they will be too fast to keep under control and will break as soon as they hit something .

They also need to be as cheep as possible and quick to build and repair as they will get damaged if not by you're own actions , it will by others crashing into you .

Steve

[Martin Harris - Moderator]

Posted by Stephen Jones on 10/05/2016 23:15:55:

Indoor models need to be as light as possible or they will be too fast to keep under control and will break as soon as they hit something .

Steve

 

Some rather porky receivers above - this 7 channel receiver can be half their weight with the optional heat shrink removed! I would imagine that much of the saving is in the absence of connector blocks - keep the solder light though - no big blobs!

I doubt that many people would move systems to take advantage of this 1g receiver (even including its telemetry capability!) but I wonder if the examples above could benefit from a little surgery to remove the connector housings and pins and take direct connections from the servo leads to the PCBs? Perhaps consider providing a power bus from one or two outputs and just run individual signal leads for even more weight saving...

 

Edited By Martin Harris on 11/05/2016 00:12:01

[Frank Skilbeck]

Stuart have you seen the light weight spectrum Rx's from Micron

[Stuart Marsden]

Thanks will have a look

[onetenor]

Try Microlite DSM2 6 channel "1 1/2 x "1/2 Gear Best or Bang Good

[Stephen Jones]

Hi ,

I think the one Simon has already suggested is a good option ,

As it has the correct sockets for those tiny servos,

Or the Frsky Futaba compatible .

And i don`t know how good you're eyes are but i could not solder wires on that tiny nano receiver .

Steve.

[Stuart Marsden]

Thanks for this, my eyes definitely won,t be tackling the soldering. I will look at these options.Where do you generally find the best place or site to purchase from?

[Former Member]

[This posting has been removed]

[Denis Watkins]

Hobbyking has the orange, and microelectronics has other alternatives

[Denis Watkins]

Sorry, Micron electronics UK

[Stuart Marsden]

Many thanks

[John C]

Posted by Frank Skilbeck on 11/05/2016 08:21:42:

Stuart have you seen the light weight spectrum Rx's from Micron

This is a DT Rx31 (from Micron Radio Control) - a 6 channel rx which weighs 0.21g. The wires are 0.2mm diameter enamelled copper from **LINK** You get 2m lengths of red, black and self coloured wire which is helpful for identification. A magnifying glass on a stand and a temperature controlled iron with a fine bit were used.

The servo wires were cut back to within 15mm of the servos and the soldered joints insulated with Plasti Dip. I now use Electrolube Flexible Silicone Coating to insulate these joints and also to coat the bare PCB of the RX and the ESC (because I fly this model outside as well as indoors and the grass is sometimes wet).

All the wires and covering were removed from the ESC. I have soldered the motor wires direct to the ESC and also the cut down cable for the lipo socket. This all saved weight. The lipo is in a cutout centred at the COG.

I am pleased that I have managed to build this Twisted Hobby's 24" Edge 540 with an AUW ex lipo of 69g. It flies very well and is delightfully floaty.

[ernie carter]

new to this game having read some of the above, I assume a 4g servo weighs 4 grams and 9g nine. Am I correct and does the higher weight mean more power to the moving surface?

[john stones 1 - Moderator]

Yep that's the weight..all servos have the specs listed to tell you the torque + speed there's a wide range to choose from in the various sizes Ernie.

[Simon Chaddock]

ernie

Like most manufacturers specifications they do need a bit of care.

On a very light servo the weight of the cable and plug can be significant. The quoted weight is usually just the bare body with no cable, plug, servo arm or retaining screws.

For example a 3.7 g servo actually weighs 5.4 g when you include everything. That's an additional 45%!

Obviously with bigger heavier servos the proportion of the 'extra' is much smaller.

[Phil Green]

Also check the servo working voltage - conventionally servos are 4.8v - 6v, micro servos can also be 4.8-6 or can be 3.7v (ie designed to run off a single lipo cell) and which type you choose depends on your rx and flight pack, single cell (3.7v) or pack (5v via BEC). Most 4.8-6 servos will work on a single cell but are noticeably slower.