RC Valve Controller Development

[Rapidrory]

Following a conversation with Mario at the Champs today, and previous conversations with Will, it seems that there is a lack of cheap and simple RC switches suitable for controlling pneumatic solenoids / relays etc. I developed one as a one off for Manta a while back, so I have all the code and basic designs for one. What I'm wondering is whether it would be worth developing a proper PCB and getting them printed professionally to sell. (The reason why I'm willing to sell these rather than my FW and HW ESCs is that they are much much simpler and easier to put together in large quantities)

The kind of specs they're likely to have is as follows, based of the one I built for Will:

12A continuous max
Up to 80v input
3 channels (eg, throttle stick up for flip, center for dump, down for self right)
Gear channel to arm/ disarm
Small (likely to be quite a bit less than 5cm square, though until I've developed the layout I can't give an exact figure)
~£20 - £30 (again, not sure on exact components so price is subject to change)

What I need to know is how many channels do most people usually use (the less the better really)? Also, would people actually want the arm and disarm feature? It is mainly in there as the throttle channel does not failsafe correctly on some receivers, so the Gear channel is checked for the fail safing. However it is also used to arm and disarm the RC switch so that there's no chance of accidentally firing it by knocking the throttle channel whilst arming (I have it on Richie's lifter and I find it really quite a useful feature).

I've got exams coming up so am unlikely to get anything for sale until the end of June at the earliest, but I just want to do some market research so to speak to see how many people would be interested, and what features people would want..

[mattsdragons]

Think it would work as a simple on/off relay for weapons such as lifters too? That being if you could up the A rating a little?

[Danjr1]

When i designed a low pressure flipper based around a high pressure architecture, the issue I would have wanted to overcome using some kind of control system is the amount of time the valve is open as I would never be able to control it effectively by sight which would mean a loss of co2. Therefore, would it be difficult to add in an adjustable "open valve" settings which would reset when the control returns to its normal position?

[Max]

Just thinking out loud, the problem with having the dump in the centre for the throttle stick is that on most tx's the throttle channel doesn't spring back to centre, and if down is self right you need to be carefully not to manually pull the stick down too far as you will then just fire the self right valve. Ideally I guess you want it on a stick that does spring to centre so you can just quickly flick it up to fire and release and it will dump.
Not sure how the heavy guys get round this, I've always used the rudder channel to control flippers but it is a pain in the arse as I always forget which direction is fire.
In conclusion, I haven't really helped at all but hopefully food for thought!

[Rapidrory]

Apparently there are equivalent products available for a similar sort of price range such as these RC Relays.

All mine would be is a smaller solid state version for a similar price with maybe a few extra features, so the market for custom controllers seems to be substantially smaller than I originally thought.. They'd be useful in Beetleweighs and Featherweights which are pushed for space, but unfortunately I can't see enough need for it to be worth getting a professional print run done, unless anyone can think of a suitable application?

[maddox10]

I looked earlier at the technobots stuff.

The Battleswitch, even if I had good experiences with 1 in the past, nothing else indicates that those are useable in our machines, I didn't meet a roboteer yet that can say it's a good switch.

The Technobots switch can't take more than 30v, and that seems the cut off for most available switches.

It is perfectly possible to use a lower voltage RCswitch to switch another relay that switches the main relay. But that introduces more points of failure.

In short, every machine that uses a solenoïd to control something needs an RC switch, and as long the voltage isn't higher than 6S, commercialy available stuff will do the job. It's when you go over that 6S it gets tricky.

What Team RCC is searching for is a dependable source that delivers the goods.
For Hannibalito 3,2 it's simple. Just an on/off switch. Throttle up, 36V goes trough, valve activated. Throttle centre or down, valve closed.

Bullfrog. Stick center or down, valve 1 activated. Stick up, valve 2 activated.

Another machine needs a switch that is a bit more tricky. But the one as used in Manta can do the task. Stick neutral, nothing happening. Stick up, solenoid 1 activated, stick down, solenoids 1 and 2 activated.

[Rapidrory]

As long as it doesn't need more than 2 separate output channels, it should be fairly simple to make one that is less than 20x20x10mm. It'd likely have an output of 5 to 8A at well over 36v depending on what suitable components are available, so that should be ok to drive 2 Burkets in parallel.

Next time I get a load of stuff professionally printed I'll see if I can tack a few dual channel switch boards onto the order (they'd also be used for single channel switches; just leave some of the components off)

[blazerbotics]

I've had noting but trouble with the Battleswitches, they constantly misfire. I've used alot of the Technobots RC Relays and they've been fine.

What might be useful is a switch with a timed output, so it just pulses instead of staying on, would be good for electric axes and the FP pneumatic flippers.

[beast]

Beast2 has a techno switch relay and is no problems firing 2 burkets

[Rapidrory]

Well, I had to make a Farnell order up to £20 for the free shipping, so I ordered some parts to try out these valve controllers. Put together a little dual channel one on prototyping board, and this is what I've got:

11160108_10152785268301845_634706916_n.jpg11160085_10152785268481845_70453873_n.jpg

(Just shows top and bottom sides of the board with an antweight motor for scale; currently ~22mm square)

All seems to work fine during the limited testing I've done so far; It'll run a 550 motor at 12v under load without getting too warm, and seeing as it should be good for 8A at 100v I'm guessing it'd fire a Burket valve just fine.

If I did get enough interest to do a production version, it'd likely be ~50% smaller and wrapped in heat shrink. The firmware is also fairly crude (thrown together for testing), so that'll need various improvements before it's suitable to use.

[Rapidrory]

Upgraded the firmware to make it useable and added some heatshrink. It's currently set up so one channel is on when the stick is up, the other is on when the stick is down, and both are off in the middle. I'll be bringing it a long to Portsmouth on Sunday, so if anyone there has a Burket they can let me test it with (or better yet, a robot to stick it in!), then that'd be awesome

[terry]

Ed Wallace would have tested that at burgess hill as he needed one ! By farnell do you mean cpc farnell ? As if you do a web order it's free delivery after £10.

[terry]

Would you be able to make this controller with centre off, up will be on and the down could be a timed on switch adjustable between 0.1 seconds and 1 second ?

[Rapidrory]

... Could've sworn it was £20... Maybe I'm getting RS and Farnell mixed up. Either way, I now have a prototype valve controller and parts for 6 more :L
(EDIT: Farnell is £20 for free shipping, CPC is only £10... might have to start looking at CPC again..)

And yeah, would be a fairly small firmware change to make a timed switch, though to make it adjustable could be more of a pain :L

[terry]

It would have to be adjustable as it would open my valve just enough for a self right flip.... And I think that's around 0.25 second press of my tx button !