Radio Link 2.4GHz Tx & Rx

Hi guys,

Found this link over on the Robotwars101.org forum. It's a 4 channel transmitter and receiver kit on 2.4GHz for £25.48:

http://www.giantcod.co.uk/gianitcod-24g ... 03779.html

Peter Waller has ordered one to do some testing on and see how it fares, but after reading reviews on the website (average rating 4.91 out of 5) I have ordered myself one too. It came to just over £28 to have it delivered first class insured.

I will be testing it in both Carcinus and Drumroll to see how it performs and to see what it is like with failsafes. According to the site it sounds like it behaves in a similar manner to the Planet 5 kit in that upon loss of signal it continues giving out the last known good pulse for a second or two then cuts all signal and outputs nothing. The 6ch receiver case looks a lot more sturdy than the Planet 5 one. It's very similar to the Futaba 2.4GHz receiver, except it has one aerial instead of two. The transmitter is effectively an old Skysport 4 shape, with cheap metal coverings bearing the Radio Link logo etc. Anyone who has seen my Skysport 6 though will know what I've got in mind for mine :)

The reviews say range and reception is excellent; it has got a CE marking so doesn't exceed 100mw (although I believe the exact RF output is unknown). I ordered mine with a minimal guarantee, meaning that if it is defective on arrival I can get a replacement/refund but if I break it in use I can't. That's why they can offer it at such a low price apparently. You can pay extra (not sure how much) to have a normal guarantee period incase you do break it within the first however many months though.

It's got the usual channel reverse switches, but no dual rates. Also has V-Tail/Elevon mixing built-in, and a charging socket if you wish to use rechargeable batteries. No instruction book, no fancy packaging. Just cheap and cheerful :)
Will let you know how it performs.

Quote:

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Originally Posted by k_c_r

Anyone who has seen my Skysport 6 though will know what I've got in mind for mine :)

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I take it you found some more blue metallic paint then :proud:

Good luck with the testing though, hope it proves to be worth all the praise. 2.4ghz seems to be getting cheaper and cheaper now, if only I'd waited for this before spending £300 on a DX7 :P heh.

Quote:

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I take it you found some more blue metallic paint then :proud:

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No, not yet sadly. I was just meaning painting it in general to look a bit better than how it comes, but I've got a little bit of blue metallic left and Drumroll's fully painted so I guess it might as well be metallic blue :)

A quick eBay search pulls up several DX7s going for £200+ for transmitter only, if you wanted to sell and buy cheap. But looking at the pics on eBay at least it's a pretty sexy looking transmitter :lol:

[quoteA quick eBay search pulls up several DX7s going for £200+ for transmitter only][/quote]
yes but Joey must have brought one ages ago

and its like pc stuff comming down all the time ;)

ps you realy need a 5 chan so you can use a WEAPON (ban boxes)

you dont need 5 channel for weapon robot with this tx you could have 2 weapons

Yeah the minimum you need for a weapon is 3ch. Drumroll's drum is on Ch3, if I had a self-righting arm on it, it would be on Ch4.
Personally I find Ch5 to be a bit restrictive for some weapons as the switches tend to be On-Off, or fwd-bck with no middle ground. Obviously you could replace this with an On-Off-On switch or an adjustable dial if you wanted to but that's hassle :P
I know some spinners use the switch if the weapon is just relay-controlled, but for electric axes/lifters, I would find it much more flexible and controllable on a stick channel. What do flippers tend to use? Can you just get by with flicking the switch on to activate the valve and then rely on the elastic to retract the flipper plate?

Received the item today. As mentioned on the website, no fancy box, just packaged in a sturdy jiffy bag. May sound a bit minimal for a transmitter but there was strong foam packaging surrounding the sticks to prevent damage, the aerial was folded down and the whole thing was wrapped in an extra layer of bubble wrap.

The transmitter. Metal trim isn't quite as tacky looking as I was expecting but I'm still gonna paint it I reckon :)

[attachment=2:39t7u8dq]DSCN4829.JPG[/attachment:39t7u8dq]

Mixing switch, a bit fiddly to get to but it's mixing nonetheless

[attachment=1:39t7u8dq]DSCN4833.JPG[/attachment:39t7u8dq]

The receiver, pretty sturdy case

[attachment=0:39t7u8dq]DSCN4834.JPG[/attachment:39t7u8dq]

Bind button (circled in red)

[attachment=0:ovobhvwj]DSCN4835.JPG[/attachment:ovobhvwj]

Transmitter gets turned on, receiver powered up and then this button is pressed. Should take a few seconds apparently.

I've not had the chance to try it out yet but will be home this weekend so will see how it performs. The battery bay will accept 8xAA batteries but the two leads connected to the positve and negative terminals can be cut and have a plug fitted on them so a typical rechargeable back can be fitted instead. I'm assuming the charge socket will just function as normal then but again, I will investigate this weekend.

There is also a space in the battery bay to carry a spare set of cryst......oh, wait :)

Okay, home for the night so had a chance to set up the Radio Link set. First up was mods; in this instance, all that consisted of was removing the metal springs in the battery bay for holding AAs in place so I could fit a standard rechargeable pack and then fit a Futaba plug on the transmitter battery leads so that I could plug the battery in. Job done. I also removed the trainer jack while I had the thing apart since I don't need it. Plus I pulled off a couple of the metal sticker coverings just for the hell of it :)

Right, so I fired it into Carcinus and powered up the transmitter and receiver. Green LED came on in the receiver. I pressed the bind button on the receiver until the LED started blinking then let go. Blinked for about two seconds then returned to being constantly on. Bind complete. I had control over the motors and the response was very positive. I then tested its failsafing abilities; I have two Electronize 30A controllers with built-in failsafes and a 15A controller with an external failsafe. All systems failsafed correctly. I didn't check it actually without having a failsafe plugged in but I'm assuming it gives out no signal after the transmitter has turned off. Whether that means you don't need failsafes, I don't know (I don't think it does) but I will try it out tomorrow and see.

Next up I tested the mixing, all worked fine. There only appears to be one setting though so I don't know if it's Elevon or V-Tail (when using an external mixer we're always told to buy a V-Tail one but on my old Hitec remote I had to set it to Elevon for the mixing to be correct) but whatever it is it allows both drive motors to be controlled from the one stick, so suitable for the bots.

I haven't performed a long-range test yet (will be doing so tomorrow) but from driving it around my room I am really happy with the way it performs. Glitch-free control, no signs of interference - which is nice considering I could barely control the robot in my room with the 40MHz system - all in all I think I'm becoming a bit of a 2.4GHz fan :)
I know it's just masked the sources of interference rather than removing them but for keeping things low-cost and simple, it's a really good solution.

So unless anyone has any major issues with it, I would say this unit is suitable for our use. I will give it a long-range test tomorrow and then it'll get a thorough testing at Barnsley.

Have you had a chance to test it with other 2.4GHz transmitters in the area to check for interference?

Ah good point Leo! I have not been able to test this yet, so maybe some sort of testing can be arranged at Barnsley when there are other 2.4GHz units about. Thanks for mentioning that.

Tested Carcinus yesterday with it and got excellent range on it - not sure of the exact distance in metres but definetly sufficient to cope with robot events.

I've also purchased one of these and a couple of receivers. Tried the failsafe by turning off the transmitter while it was driving a motor and it worked fine although it took a second to kick in, unlike my 40 MHz which kicks in instantly. But a one second delay is perfectly acceptable for a robot in an arena. It also takes a second or so to start up when the transmitter is switched back on.

I read up that the planet 5 system uses new cheap internals, could someone break there's open and take pics , id be really interested to see if the innards are the same.:)

Crack open a Planet 5 or crack open one of these Radio Link ones? I've got a picture or two of the internals of the Radio Link system that I could upload in the morning but it's very simple. One circuit board fitted down the bottom of the transmitter casing; the sticks, LED and battery connections just plug in to it, there is a PIC chip or two, and a small circuit board that seems to be the 2.4GHz 'module' stacked on top of it (similar thing is fitted in the receiver)

So yeah it's pretty simple. Been a while since I took my Skysport 6 apart but I remember there being L shaped circuit boards fitted round the sticks and everything on that one, but for the price you pay for a Radio Link unit the level of simplicity is no surprise.

is the 2.4 ghz board a sort of small triangle with platish edges?

Just a couple of things to add.
I have found that if there is another 2.4Ghz tranmitter operating within about 300 mm of the receiver when the system is switched on the receiver never seem to lock on to the transmitter. This is in normal operation not binding. If the other transmitter is switched off or moved further away control is established and then placing the transmitter back in close proximity to the receiver has no effect. Not a major problem but I was doing some tests with other transmitters to check the operation and thought the system had stopped working.
The other thing is the failsafe as stated above all four channels stop outputting pulses when the signal is lost so you are reliant on the speed controllers for failsafe. On the throttle channel when the signal first connects or reconnects the receiver outputs the minimum 1ms pulses until the throttle stick is placed in that postion then the pulses follow the stick. Strangely that is stick full forward as standard so you need to reverse the throttle channel.
All round I am most impressed for a £15 Transmitter and a £10 receiver.
Receiver size and weight are a little high for ants but as the receiver is 12.5gms and its case accounts for 6gms there are ways to reduce it.
The RF part of the receiver is on a tiny daughter board 23 x 15mm see picture:
http://i109.photobucket.com/albums/n66/ ... MG0922.jpg
I am looking at the possiblity of building a dual controller board that sits on the servo connector pins and fits within the existing size of the receiver.
I will need to replace those two large capacitors.

I now have a working antweight controller running.
Here is the receiver insides as it comes.
http://i109.photobucket.com/albums/n66/ ... MG0922.jpg
I have managed to replace the two large capacitors with small surface mount devices and removed all but 5 of the pins and turn the arial and it still works.
http://i109.photobucket.com/albums/n66/ ... MG0937.jpg
The built up board looks like this:
http://i109.photobucket.com/albums/n66/ ... MG0939.jpg
Fully finished it looks like this with a standard receiver next to it:
http://i109.photobucket.com/albums/n66/ ... MG0942.jpg
Original Receiver....... 44 x 30 x 17mm and 12.7 gms
Controller Module...... 42 x 27 x 11mm and 11.5 gms

Nice job. Very impressive.

I asked the chap at Giantcod if he could confirm that the RadioLink gear has CE approval and if he could publish the documantation and got the following reply.

Yes I can confirm it.
I will put all the cerficates on the site later.
Regards,
Rob.
www.giantcod.co.uk

Used the Radio Link Tx/Rx combo in Carcinus for a fair few fights at Barnsley at the weekend.

In general, in performed very well. The robot failsafed without any problems both on the bench and in the arena. Signal wise, there were no problems in the arena, full control was retained for the duration of all its fights.

However, the issue Peter describes above of the transmitter and reciever not conecting when turned on in close proximity to other 2.4GHz sets occured during arming-up in one battle. We tried turning it off and back on again several times but signal couldn't be established. We removed the robot from the arena and tried again when it was on the pit bench (away from all the other active 2.4GHz sets) and it connected fine.

There are two or three ways I can think of to get round this:

1) Use a seperate Rx battery supply (i.e. not a BEC) and turn on the transmitter/receiver when you first take your robot into the arena (before everyone else turns their transmitter on). This way your tx/rx can connect without interference yet there is no risk of your robot's drive or weapon moving due to the fact that the link still needs to be plugged in. We did this for the fight after we had the connection problem and it worked fine.
2) Wait till everyone else has turned on their transmitters (and keep a bit of distance between your robot and others) and then turn on your transmitter.
3) Possibly a bit of a hassle, but mount your receiver/design your robot in such a way that you have a small access hole through which you can stick a thin screwdriver to press the bind button on the receiver and renew/re-establish the connection if needed.

This issue may sound rather troublesome but hopefully this shouldn't happen every time you arm up. It only happened during one battle out of six over the weekend for us; I guess it just all depends on the circumstances at the time.

That aside, for £25 it performed rather well and is a nice option for those just starting out building a robot in need of a transmitter/receiver.

Just to add too for anyone who's not had a look round the site, GiantCod also have a 6ch version for £52:

http://www.giantcod.co.uk/giantcod-24gh ... 03852.html

It is computer programmable and looks very similar to the Field Force 6 in terms of its buttons etc.

Also, for those who use Deans connectors, they sell ten pairs for £4. They're not actual Deans but an equivalent make and according to reviews, they work very well on their own or used with proper Deans conenctors. A nice money-saver:

http://www.giantcod.co.uk/deans-style-u ... p-208.html

Forgot to add, I ran Drumroll in a busy whiteboard at the weekend on 40MHz. The robot has no suppression components fitted. I think every other robot in the fight was on 2.4GHz and I wasn't aware of suffering intereference at any point throughout that fight.

The rules change in 2011 for featherweights so it probably doesn't matter too much but based on this (and I know it's only one case, so not very conclusive) the 2.4GHz units aren't drowning out the 40MHz users.

Copied from the antweight forum, a copy of the CE certificates. There was some doubt cast over the legitimacy of the CE marking on the transmitter:

http://www.giantcod.co.uk/forum/downloa ... &mode=view

Not sure why the CE marking on the actual transmitter is different from the way it's supposed to look, but it seems correct on the certificates.

Sorry to dredge up an old thread but just got a point to mention and a question to ask:

The effects described above about the tx/rx not connecting when switched on while other 2.4GHz units are being powered up in close proximity occurred again at Edinburgh. It was the first fight and I had forgotten to turn on the tx and rx switches before everyone started powering their Spektrum units up. For all the following fights I took this approach and there was no problem.

After the end of the last fight though, I powered the robot up just to check everything was still running and once again I had the problem of the tx/rx not detecting each other. This time there were no other 2.4GHz units in use, and even once I was home and tried it again, the same thing happened. I've tried re-binding it and using different receiver battery packs etc but still no luck. I haven't had time to thoroughly try and diagnose the problem, but I'm beginning to think that this is a problem that I don't want happening during something like an important UK champs fight, so I'm looking to get a different 2.4GHz unit as part of the new Drumroll build.

My question is, for those of you using the Planet 5 systems, has this sort of problem ever occurred during the arming up phase in a battle? Or am I better off just spending a bit more on, say, a DX5e and getting a reliable connection?

Thanks

Quote:

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Originally Posted by k_c_r

Sorry to dredge up an old thread but just got a point to mention and a question to ask:

The effects described above about the tx/rx not connecting when switched on while other 2.4GHz units are being powered up in close proximity occurred again at Edinburgh. It was the first fight and I had forgotten to turn on the tx and rx switches before everyone started powering their Spektrum units up. For all the following fights I took this approach and there was no problem.

After the end of the last fight though, I powered the robot up just to check everything was still running and once again I had the problem of the tx/rx not detecting each other. This time there were no other 2.4GHz units in use, and even once I was home and tried it again, the same thing happened. I've tried re-binding it and using different receiver battery packs etc but still no luck. I haven't had time to thoroughly try and diagnose the problem, but I'm beginning to think that this is a problem that I don't want happening during something like an important UK champs fight, so I'm looking to get a different 2.4GHz unit as part of the new Drumroll build.

My question is, for those of you using the Planet 5 systems, has this sort of problem ever occurred during the arming up phase in a battle? Or am I better off just spending a bit more on, say, a DX5e and getting a reliable connection?

Thanks

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Jamie,

Planet 5 has always worked fine for me with absolutely no issues with respect to binding and the like. What I do dislike about it is the way it is bound. You press the button and turn the tx on with no other action needed. This means if you get a scenario where you press your button and someone else turns their tx on, your robot is under their control. A lot less likely when you have to pull a bind switch.

Also I read that the throttle channel fails safe to the position your turn it on at. I've not tried this but something to consider when using the throttle for the spinner.

Anyway, have found the planet 5 to be a fantastic little set but hopefully someone will have looked at the issues I've raised. Personally though I would want digital trims for anything which is as nasty as drumroll because everything then turns on how i want it to without any chance of me making a mistake.

Andy

Thanks for the info Andy. The binding issue you described can happen in a similar way with the Radio Link sets. You power up the tx then press a bind button, so if any other Radio Link tx is on in the vicinity there is a chance that the receiver will bind to another unit. I guess it's just a potential risk associated with cheap 2.4GHz units.

Had a bit of trims discussion at Edinburgh actually. Liam's robot was always moving when the link was plugged in and it took a while to realise that the trims were miles out; it couldn't be seen because they were digital. I said then that I prefer mechanical trims because you can see where they are positioned, but I hadn't considered the benefit of digital trims that you have mentioned.
Common sense would dictate that you check all your stick positions and trims before powering things up but we all know most of us never do. I tend to just assume that they will be set in the position I left them in, which is a habit I should probably try to break. I always try to position my robot in such a way that the wheels are off the ground during arming up, just in case of offset trims and the locking pins help out in the event of weapon trim offsets. I guess seeing the mechanical trims having been knocked out of place is fine, the only problem I find after that is trying to remember what position they should be in! :roll:

the support on giantcod is terrible, my reciever is broke and after creating a support ticket i have had no reply in 48 hours.
going to phone them later.

I am suprised at that when I thought I had a problem with a receiver they were very quick to respond something I didn't really expect on such a low cost item.
Mind you 48hours from your post means you complained Saturday lunch time so they probably didn't pick it up until this morning.

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Originally Posted by peterw

I am suprised at that when I thought I had a problem with a receiver they were very quick to respond something I didn't really expect on such a low cost item.
Mind you 48hours from your post means you complained Saturday lunch time so they probably didn't pick it up until this morning.

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your probably right, i think il wait another day.
EDIT: just got a email, have to send the receiver and trasmitter back for testing.

Before you do that have you checked that you have bound the transmitter and receiver together correctly.
See procedure cut from their site.

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The bind procedure is the easiest, quickest, no fuss seen to date, this is done by powering up the transmitter and receiver, then a tiny button positioned at the end of the receiver case is pressed once. A green LED flashes for a second or so then stops, that€™s it, job done!

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Quote:

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Originally Posted by peterw

Before you do that have you checked that you have bound the transmitter and receiver together correctly.
See procedure cut from their site.

Quote:

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The bind procedure is the easiest, quickest, no fuss seen to date, this is done by powering up the transmitter and receiver, then a tiny button positioned at the end of the receiver case is pressed once. A green LED flashes for a second or so then stops, that€™s it, job done!

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tried that, i did have it working fine before. not sure why it broke.

There's a new GWS 2.4GHz 4-channel transmitter available on the Robot Marketplace. Its $32 (£21) and you can add a 4ch receiver for $10 (£7). Roughly the same price as the Radio Link tx/rx combo if you ignore shipping and import taxes etc.
I just brought it up because it's designed more like a video game controller, which I thought was quite cool and I'm tempted to give one a try the next time I order from RMP, mainly for the novelty factor of having a funky controller :P

There are a couple of reviews on the page though that state that it only failsafes on one channel, but you can get round that by connecting a complete robot kill switch to that channel.

I've still to have a read of the instructions to see if there are any other issues etc but just thought I'd flag this up for anyone interested :)