ericrw Posted March 27, 2018 Share Posted March 27, 2018 I`m having difficulty in sourcing a JR/Spectrum on/off switch with a signal wire ! The on/off switch that I have, does not have a signal wire, resulting in no power for the throttle. I have searched on ebay but to no avail !! Can you help ?? Quote Link to comment Share on other sites More sharing options...
MattyB Posted March 27, 2018 Share Posted March 27, 2018 Not sure I understand... Are you trying to put a stich in series between your battery and ESC? Definitely NOT a good idea... Quote Link to comment Share on other sites More sharing options...
Cuban8 Posted March 27, 2018 Share Posted March 27, 2018 Eric - RX switches don't need the third signal wire, so I fear that your search will be fruitless. As Matty says, are you thinking of using a switch in an unusual way? More details please. Quote Link to comment Share on other sites More sharing options...
Denis Watkins Posted March 27, 2018 Share Posted March 27, 2018 I thought all JR switches had a signal wire Quote Link to comment Share on other sites More sharing options...
Neil Byrne Posted March 27, 2018 Share Posted March 27, 2018 Hi The third core is usually so you can bind the rx using the binding plug in the charging socket on the switchRegardsNeil Quote Link to comment Share on other sites More sharing options...
John Lee Posted March 27, 2018 Share Posted March 27, 2018 The signal wire on the JR switch is there for the DSC connection - you can operate the model with a flylead from JR transmitters without the Tx radiating a signal. It was useful in 35Mhz days so you could set up your model without needing the peg. They are still available from Inwoods amongst others, be prepared to gulp at the price though! Edited By John Lee on 27/03/2018 15:27:32 Quote Link to comment Share on other sites More sharing options...
Peter Christy Posted March 27, 2018 Share Posted March 27, 2018 Yes, that's the heavy duty JR switch harness. It may be pricey, but it is the best that money can buy. I've used them for years on helicopters - a pretty harsh environment for switches. It will outlast cheaper switches many times over! -- Pete Quote Link to comment Share on other sites More sharing options...
Cuban8 Posted March 27, 2018 Share Posted March 27, 2018 Never used DSC or similar, so one learns something every day. Quote Link to comment Share on other sites More sharing options...
ericrw Posted March 27, 2018 Author Share Posted March 27, 2018 Thanks to all. I have found what I am looking for on Ebay. "Blacksmith 8104". Without the signal wire ; Ail, Elev and Rud will work but the Throttle will not. I am using a Apprentice Safe RX. Quote Link to comment Share on other sites More sharing options...
John Lee Posted March 27, 2018 Share Posted March 27, 2018 Each to their own but personally I would not purchase a single-point-of-failure flight critical component from an unknown Ebay source. I want to know the provenance of such items. Quote Link to comment Share on other sites More sharing options...
CARPERFECT Posted March 27, 2018 Share Posted March 27, 2018 Provenance is China Quote Link to comment Share on other sites More sharing options...
Geoff S Posted March 27, 2018 Share Posted March 27, 2018 I'm still unsure as to where you're fitting this switch to what I assume is an electrically powered model. If you really need the signal wire connected you could easily by-pass the switch itself and just leave it connected all the time. Nothing will happen if there is no power ... bit it still seems a bit odd to me. Geoff Quote Link to comment Share on other sites More sharing options...
ericrw Posted March 28, 2018 Author Share Posted March 28, 2018 This particular RX needs to be switch on, whilst holding it steady on the runway, to allow the ele, rud and elev to do a "dance", then she is read for flight !!! Quote Link to comment Share on other sites More sharing options...
MattyB Posted March 28, 2018 Share Posted March 28, 2018 Sorry, I still don't get it. Why don't you just have everything power up off the UBEC when you plug in the lipo? You can still configure a throttle cut on your TX if you are worried about the prop. Or are you using an auxililiary receiver pack to power the RX? Posting a circuit diagram may enable us to provide more useful help. EDIT - Found this in the Apprentice instructions. Looks to me like HH inserted an arming switch in the ESC itself in that model for safety; I can't think of any reason why the SAFE functionality wouldn't work without though, with safety addressed using a throttle cut at the TX. Edited By MattyB on 28/03/2018 10:50:43 Quote Link to comment Share on other sites More sharing options...
Former Member Posted March 28, 2018 Share Posted March 28, 2018 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Dickw Posted March 28, 2018 Share Posted March 28, 2018 An ESC “arming switch” can be just that and not control the ESC BEC power to the Rx. For some competitions I got two models ready to fly “just in case” and had to plug in the Lipo before putting the wings on, then perhaps wait 10 minutes or so before flying. In these circumstances a switch is essential so I have made up switch harnesses between ESC and Rx for BEC powered Rx. Some stabilised receivers may need the plane to be held level and steady at Rx switch on so plugging in upside down may be a problem. A switch between ESC and Rx again solves that problem. It’s a workable solution whatever the reason you might want to use it. Dick Quote Link to comment Share on other sites More sharing options...
MattyB Posted March 28, 2018 Share Posted March 28, 2018 OK, I think I get it now. It sounds like Eric is installing this RX in model without the original ESC with the switch; instead he is placing a switch between the ESC BEC output and the receiver so the battery can be installed and connected in any orientation, then the RX switched on once it is back on it's wheels and level. Disadvantage of the above (assuming it's correct)... Eric is going to be applying power to the ESC and motor without a signal from the TX. That means he is relying solely on the safety features of the ESC to prevent the motor powering up whilst the switch between BEC and RX is off and the ESC is not receiving a signal from the TX. You could argue that is no different to what HH are doing with their own ESC, but for me the difference is that their ESC is designed to be able to power an RX without providing power to the powertrain. Based on my experience I am yet to see a modern ESC that will apply power to a powertrain without an input from a TX, but would I want to rely on that functionality as the sole way of disabling the prop on power up? Personally I wouldn't be comfortable. Instead I'd look to use an ESC like HH's original that is specifically designed for this task, or simply carry a separate RX battery and disable the BEC completely. Edited By MattyB on 28/03/2018 13:53:40 Quote Link to comment Share on other sites More sharing options...
PatMc Posted March 28, 2018 Share Posted March 28, 2018 It seems to work for Dick & presumably many other fliers he competes with. Quote Link to comment Share on other sites More sharing options...
MattyB Posted March 28, 2018 Share Posted March 28, 2018 I didn't say it wouldn't work, just that I personally would not have confidence in using that method. I have seen a few electric models go banzai across the pits due to an unexpected startup (though admittedly not for quite a few years); it is never a good thing and the damage to property and flesh stays with you! Edited By MattyB on 28/03/2018 15:22:44 Quote Link to comment Share on other sites More sharing options...
Dickw Posted March 28, 2018 Share Posted March 28, 2018 How is disabling the BEC and using a separate (switched?) Rx battery any different to disabling the BEC with a switch in the ESC>Rx red wire and not using a separate battery? Both rely on the ESC remaining stable without a signal from the Rx. Many of my models have the main battery connected to the ESC before I switch on the Rx – either from the BEC or a separate battery – not had a problem yet in around 30 years operating like that. Golden rule – keep clear of the prop once the battery is connected however you chose to do it. Dick Quote Link to comment Share on other sites More sharing options...
MattyB Posted March 28, 2018 Share Posted March 28, 2018 Posted by Dickw on 28/03/2018 15:25:00: How is disabling the BEC and using a separate (switched?) Rx battery any different to disabling the BEC with a switch in the ESC>Rx red wire and not using a separate battery? Both rely on the ESC remaining stable without a signal from the Rx. If there is a separate power supply for the RX there is no need for the ESC to be powered up but unable to see a signal from the TX - just turn on the TX first, check it is at minimum throttle with any throttle cut enabled, then turn on the RX power supply followed by the main battery. At the end of the flight simply reverse the process. As was drilled into me from the FM days, "The TX must always be on longer than the model" - that means the TX is always switched on first and off last ensuring the RX can alway see a signal whilst the motor and servos are live. You could make a case that this is moot in the days of 2.4 where systems consistently "play dead" when not given a signal, but because I still have a couple of models on 35MHz I like to operate consistently so I don't make an absent minded mistake. YMMV. Edited By MattyB on 28/03/2018 15:55:14 Quote Link to comment Share on other sites More sharing options...
Dickw Posted March 28, 2018 Share Posted March 28, 2018 I always turn on the Tx before the Rx and off after the Rx, but I am happy to connect the ESC main battery before the Rx is on (from way back in the 35Mhz days). If you think about it, when powering the Rx from a BEC as you describe the Rx is dead at the point of connecting the battery and won’t send a signal to the ESC until after it has powered up and acquired a signal from the Tx. This delay is very short by human standards (could be up to a second?), but for a microprocessor? The ESC deals with this by not arming until it sees a valid signal from the Rx. If you connect up an ESC and switch on the Rx sometime later the ESC arming tones will come at Rx switch on not at ESC connection – its just a bit longer delay as far as the ESC is concerned. In my experience the biggest risks always come at a “change of state” – connection, switch on, etc. - not while the model is just sitting there in whatever state it is left. I use both methods depending on model and practicality, so am happy either way. Dick Quote Link to comment Share on other sites More sharing options...
MattyB Posted March 28, 2018 Share Posted March 28, 2018 Posted by Dickw on 28/03/2018 16:15:00: I always turn on the Tx before the Rx and off after the Rx, but I am happy to connect the ESC main battery before the Rx is on (from way back in the 35Mhz days). If you think about it, when powering the Rx from a BEC as you describe the Rx is dead at the point of connecting the battery and won’t send a signal to the ESC until after it has powered up and acquired a signal from the Tx. This delay is very short by human standards (could be up to a second?), but for a microprocessor? The ESC deals with this by not arming until it sees a valid signal from the Rx. If you connect up an ESC and switch on the Rx sometime later the ESC arming tones will come at Rx switch on not at ESC connection – its just a bit longer delay as far as the ESC is concerned. In my experience the biggest risks always come at a “change of state” – connection, switch on, etc. - not while the model is just sitting there in whatever state it is left. Fair point re: the case where an ESC BEC is being used without a switch anywhere in the system - the RX must be dead for fractions of a second (I use FrSky which boots up near instantaneously unlike some of the early 2.4 implemntations) with the main battery is first connected. Based on that I suppose you must be correct that powering an ESC without a signal to it is safe, though I can definitely remember some ESCs in the early days of electrics (NiCads and brushed motors etc) that were very much "live" the moment a battery was plugged in, and could be very dangerous as a result (especially given the frequency control challenges of 35MHz)! Edited By MattyB on 28/03/2018 16:25:35 Quote Link to comment Share on other sites More sharing options...
ericrw Posted March 28, 2018 Author Share Posted March 28, 2018 The new switch works OK... Do not worry Lads, I will be careful !!! Quote Link to comment Share on other sites More sharing options...
Former Member Posted March 28, 2018 Share Posted March 28, 2018 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
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