safety issues

**widow_twanky** · 4th November 2009, 18:17

Originally Posted by muchalucha

Apparentyl there hasent been any problems yet but they dont use encritptionas good as those with spektrums or futaba systems.

That's not quite the case if you understand the technology a bit (which I have had explained to me but can't really claim to understand it fully).

The 2.4ghz protocol works on the basis of 'packets of information' which are sent between bound receivers. If a channel gets busy then it can get back up the information delivery (IE: your wi-fi which could be 2.4ghz can do the same if a lot of people are on line).

The encryption is the same, it all works on the same protocol.

What Fatuba and Spektrum have done is use the protocol to develop a top end system which operates well using channel hopping etc to make sure the flow of information is quick and reliable.

On the Planet 5 this was originally marketed as 'FHSS' which is the Fatuba protocol. If you get a set now this will be covered up with a sticker. I'm not sure of the reasoning behind this but I assume it is because of trademarks etc. The fact that this was on there seems to indicate it uses some form of channel hopping, whether it is as good as the Fatuba remains to be seen but it's not difficult programming to achieve it.

These transmitters are still relatively untested. From what I've seen I'd be quite comfortable to use them in an antweight or a feather but I don't really think they've proved themselves enoughtfor me personally to use them in one of the heavies. I'd just rather make sure there aren't any issues with speed of response or signal congestion or things running away before getting Pete to chase it round the arena when it's out of control!

Andy

**leorcc** · 4th November 2009, 18:47

Frequency-hopping spread spectrum (FHSS) is a standard method of transmitting radio signals by rapidly switching a carrier among many frequency channels. It is not something from Futaba. You are confusing it with FASST which is a Futaba trademark. FASST uses FHSS in its protocol, while Spektrum uses DSSS (direct-sequence spread spectrum) in its DSM and DSM2 protocol.

**widow_twanky** · 4th November 2009, 19:05

Originally Posted by leorcc

Frequency-hopping spread spectrum (FHSS) is a standard method of transmitting radio signals by rapidly switching a carrier among many frequency channels. It is not something from Futaba. You are confusing it with FASST which is a Futaba trademark. FASST uses FHSS in its protocol, while Spektrum uses DSSS (direct-sequence spread spectrum) in its DSM and DSM2 protocol.

Told you I couldn't claim to understand it fully!

**muchalucha** · 5th November 2009, 09:34

i did wonder what the FHSS hiding under the sticker was about

**peterw** · 5th November 2009, 13:07

I just got a coupler of new receivers and the label has been updated the FHSS has been removed.
The actual receiver board is very low profile except for the connector and the large aluminium electrolytic capacitor.
With a smaller tantalum capacitor and the connector modified I have managed to get a receiver + antweight speed controller smaller than the original receiver.
Module 9x25.5x42 mm and 10.2gms including 120 mm leads where as the oringinal receiver is 11.5x20x50 and 6.6 gms
http://i109.photobucket.com/albums/n66/ ... MG0852.jpg
http://i109.photobucket.com/albums/n66/ ... MG0855.jpg
The servo connector has been changed in the final cased version as it takes up less room and the fourth pin enables the use of full battery voltage on weapon controllers or servo.

**muchalucha** · 5th November 2009, 14:03

mr waller those are awesome !! Are those for sale ? , and if so could we buy just the receiver bit without the tx ?

**peterw** · 5th November 2009, 19:24

This is a safety discussion and I shouldn't really have gone off on a tangent so I will just say keep an eye on the robotwars101 site for more info.
On the subject of failsafes the receiver appears to continue outputing the current position on all channels for one to two seconds after the transmitter is turned off. The throttle channel then outputs the failsafe position for about 1/2 a second before stopping all output while all other channels just stop all output.

**muchalucha** · 6th November 2009, 13:29

dont the spektrum systems do that to though.

Has anybody else with a planet 5 set noticed how , if the set it is turned of with the reciver on , after it has taken its 2-3 seconds to failsafe it lightly reverses all channels for about half a second before failsafing completely , i dont think this is interference as it does it every time , anybody else's do that or is it just mine ?

edit : yay , 200 th post