The future of roboting

[terry]

Re: The future of roboting

i must admit i had lots of problems with interference on 40mhz.
all of my electronics is suppressed both when i was on 40mhz and 2.4ghz,
even though i could remove all the suppressors etc as they dont affect me
i dont wont to cause problems for others, well apart from the odd oota !
I think newly designed robots built with 2.4 will not fit suppression as they will
not have any controll problems, not realising they are creating problems for
40mhz users.

[john]

Re: The future of roboting

theres no point putting a time limit to stop people using 2.4 as do u rly think were going to be doing this in 5 years time? i cant atm

as for 40mhz its been proven way 2 many times that these shouldnt be used anymore, 2.4ghz solved loads of problems - i remember when tilly wouldnt work years ago , we plugged our 2.4ghz system into it and it started working straight away fine, pete went and brought the set off sewer snake and i doubt pete has ever gone back to using 40mhz

do shops even sell 40mhz nowadays? and isnt that spektrum dx5 like £60? should be first on the list before any robot has started to be made

[m2xt]

Re: The future of roboting

John, the only reason I can think of where 2.4GHz solved the problem for Tilly was that the 40MHz system was failing due to interference. Installing 2.4Ghx didn't solve the problem, just masked it and possibly left the interference to interfer with others. Why do you think the 2.4GHz solved the Tilly problems?

Of course 40MHz systems are still for sell and I have a number of customers who will not touch 2.4GHz. However, in general the sales are on a decline.

Also, a real issue with 2.4GHz is that they are biased towards aircraft with in general just a single failsafe channel. This leaves the other channels often staying put after loss of signal etc.. You don't get this problem with 40MHz.

[leorcc]

Re: The future of roboting

Paul is correct in so far that 2.4GHz is just a frequency, nothing else. There is no specific failsafe mechanism for the 2.4GHz band, just an agreement that equipment used in Europe are required to abide to. This creates a problem with all the cheap 2.4GHz stuff coming in illegally from China without being checked by customs which will happily exceed these guidelines by a factor of 4 ore more. I've seen a $40 usd 2.4GHz transmitter that will happily pump out 800mW EIRP (the ETSI standard is 100mW max).

By the way, have the tests as proposed previously been implemented yet?

As for interference, all our robots, from raptor to heavy have all suppression methods in place both on motors and valves. That is still a precaution all robot builders should take in my opinion, if anything as a courtesy to other roboteers.

Also keep in mind that even though the receiver might not be prone to interference, your speed controller and RC switches might be so isolating them is still a good idea. Interference is not only a problem at the antenna level but behind the receiver as well.

[muchalucha]

Re: The future of roboting

in a word no , im not dropping my 40 mhz system until i absolutely have to . And even then ill stick a spektrum sticker over the hitec sticker and hope nobody notices .

[beast]

Re: The future of roboting

sorry gotto lol (with sticker)

i just like the 2.4 spec (personaly)

[knightrous]

Re: The future of roboting

AM/FM radios are just trash regardless of frequency (I've used 27/29/36/40/72mhz units), they interfere with each other on parallel channels even with failsafes! PPM or PCM is much better, I cannot think of why anyone would use anything else in a sport that is very dangerous.

I prefer the 2.4ghz spektrum radios because they solve all the issues we had in previous years as well as provide increased safety. They require such minimal setup to get them to work in any situation, you don't need godly large antenna hanging out the robot, you can mount them right beside an arcing motor and they don't have issues. I have seen a BR6000 wedged up against the fets of an IBC speed controller, which was mounted in an aluminium box, mounted inside a plough disc and still get perfect signal (Robot called Offset).

Sounds like we have a fair few witch hunters in the crowd, too scared to sell their horse & carriage and buy a automobile :wink:

EDIT: The other benefit with spektrum is that because it runs a GUUID, stray interference or channel collisions don't affect the radio.

[m2xt]

Re: The future of roboting

Trash I think not. Once again a pro 2.4 gig believes 2.4 gig is safer, as far as I am aware no hobby radio system has been certified as offering any safety functionality. Any hobby radio can malfunction with indeterminate results as can the other systems within a robot. It's about choice, use 2.4 gig if you wish, I may well do myself but so far I have heard nothing that makes me believe that 40MHz is any less safe than before. In fact I am becoming concerned that this reliance on the perceived belief that 2.4 gig is safer is going to bite someone.

[botmad]

Re: The future of roboting

I THINK THE WORD SAFER IS WRONG !!

This is where the issues are arising when people use the word safer

In my opinion ( only my honest ) the issues that the spectrum 2.4 gig solve are interfieerance and this can be construde as a safer option as to 40meg which are far more suseptable ...

So wording is an issue when discussing pro's and con's for 2.4 V 40meg

In my opinion 2.4 is a more reliable system to use as you have minimised one issue that we have all suffered from in the past



Just my 2peneth worth ..........

[knightrous]

Re: The future of roboting

Trash I think not. Once again a pro 2.4 gig believes 2.4 gig is safer, as far as I am aware no hobby radio system has been certified as offering any safety functionality.

The DSM technology is what makes them safer, the 2.4ghz frequency itself is just like Leo said, another frequency (Although the higher the frequency, the lower the chance of environmental interference). If the 40mhz radios had the DSM-like packet based protocol built in, I wouldn't be saying that the Spektrums are safer. The Spektrum's are packet radios, unless you can find some magical source of interference that can generate data packs with the corresponding GUUID, the Spektrum radios will not suffer from interference like an AM/FM radio. You can interfere with an AM/FM radio by running an unsuppressed brushed motor that's arcing a bit, you only need the arcing to interfere with the frequency modulation (or amplitude for AM) to generate a signal that will make it past a failsafe device and cause servo jitter.

The Spektrums are like a wifi network, if you blast the 2.4ghz band with mass interference, it will just stop working as the packets can't get through the noise. FM based wifi would probably make your printer start spitting out pages of garble under mass interference.

[m2xt]

Re: The future of roboting

Pete is quite right in my opinion, 2.4GHz may offer a greater reliability for reception but that does not mean it is safer. It may offer greater security against that plane flying off into the distance out of control but any reliance to safe guard personal protection by the use of 2.4GHz is dangerous. When the bot is armed, you keep clear as any hobby radio system can malfunction and cause an unexpected response. Having spent many years specifying safety related equipment for use in industry to IEC61508 and assessing equipment to safety integrity levels (SIL) to reduce the risk of injury to personnel, I can assure you that 2.4GHz hobby radios will not even meet the minimum of safety requirements.