I purchased an interesting electronic switch from Hansen Hobbies this weekend. The switch will handle 55 volts at 5 amps, has an adjustable turn-on point, and is reversible. It was the adjustable turn-on point and reversible feature that really interested me. I'm using Pololu boards right now to turn on my solenoids and I like them, but I cannot use two on the same channel to fire different guns. Right now I'm using a transmitter mix to mix a second channel that is reversed from the first channel to fire the second board. I do at least get both the guns on the same stick, but it takes an extra receiver channel. With these Hansen boards, you can set up a pair with one reversed from the other and fire two guns from one stick using one receiver channel. And because the turn on point is adjustable, you can set up a little bit of dead band in the middle of the stick throw so that you don't inadvertently fire your guns when using the rudder, or whatever function shares the same stick. So I soldered together the kit - yes it is a kit, but don't let that intimidate you. If you can solder motor wires on, you can do this kit - they even include the solder. I tested out the turn on point adjustment and the reversing function and they both worked as expected. Because it uses through the hole component to make it easy to solder, it is not the smallest switch out there, but that really shouldn't be a problem in cruisers and bigger ships. The cost is reasonable - 1 for $12.45, 3 for $29.95 - so I'm going to have to pick up a 3 pack. http://www.hansenhobbies.com/products/rcelkits/erskit/
So you have to buy two switches to run up/down on the gimbal? So $25 and you have to solder and use a Y harness like the Team Delta boards? What is the advatange of using this particular board? I am really intrigued by the components used on this. I wonder if I can make one of these as a project. Good find. I will add it to the board list.
Advantage is the lower cost than a Delta. Plus the trigger point is variable set, i.e. not a set percentage like the Delta boards are, but adjustable across the entire throw. My only question is how fast are they.
The switch is simple enough that you should be able to build your own. I was surprised when I was reading the documentation that not only did it have a very complete explanation of how the circuit worked, but it also included the complete circuit diagram. And if you want to avoid buying a "Y" harness, you can just solder jumpers between the boards. I'm not sure how you would measure how fast they are. According to the circuit explanation, it should update every time it gets a servo pulse which is every 50 ms. I just know that there did not appear to be any delay between the time I pushed the button on my servo controller and when I saw the meter change.
Sounds quick in the circuit. Although Treaty has a rate of fire limit, I wonder if the boards will keep up with fast gun fire rates. For instance I have a couple older RAM switches that work wonderfully for as old as the design is, but has a slow on-off cycle. If the rate of fire gets too fast, they start dropping power to the solenoid (solenoid fails to open all the way). They simply cannot keep up with the rate of fire I am capable of.
I do like that as they use flip flops instead of a micro-controller you CAN build your own and use a prototype board to make it. No programming to be done which is cool. It looks like a neat project for my class at any rate.
Mike, where has having a set percentage been a problem for you? I can see if you use a stick/gimbal that it might be preferable to have the trigger point set to shorter distance / less % but with a button I see no issues with it.
Oh, not saying that a set percentage is a problem at all. I'm just one of those people that will take full adjustability over set pioints. Such as the RAM switches ... I could tweak the pot to the very edge of triggering which IMO made sure the solenoids triggered even if I short stroked the button while machine gunning. Don't know if it helped at all (and it probably didn't) but it made me feel good.
Info for the database: Weight - 15 grams with wires Size - 1.125" x 0.75" x 0.625" Function: Momentary (I would call this on-off, but momentary is consistent with the other switches with the same function) External battery capable: Yes
I had an email conversation with Mr. Pololu (not sure if that was the real name) a while back about providing their R/C switches in both a positive and negative version so two could be used on the same channel (just like Team Delta). I explained to them that it would be a simple code adjustment to do this. He was of the opinion that there was not enough interest in this capability and that it would not be profitable. I bet if everyone on this board started hounding Pololu to provide two versions, they just may do it. Steve Tyng
My question is related to the review of the hansen switch and the pololu situation mentioned above... As there are already many switches available that do the job both in price and size.. What are these current r/c switches missing that causes folks to spend a great deal of time buying and testing new switches?
I would have to agree that having a separate board for the negative version would not be profitable. However, Hansen hobbies allows you to reverse their Micro Electronic Switch (MERS) 2 by bridging two pins on the micro processor. When I look at the Pololu boards, it looks like two pins on the micro processor are free, so they should be able to use the same method. But what I really think we should be asking for is both switches on the same board. Instead of requiring two boards to switch two functions, you would only need one. And Pololu would only have to add some code and a second FET, which is cheaper. Pololu could sell it as a two function switch which should be useful in the robotics world too.
We are all looking for the ideal switch, which doesn't seem to be available yet. An ideal switch is: tiny, cheap, reliable, easy to hook up, switches a boat load of current, handles up to household voltages, has programable set points and and switches two or more functions using one channel. All of this is available, but not together. Most of the available switches are very expensive for what you get. The cheap, small ones, like from Hansen and Pololu, only have single functions. So we keep looking for a slightly better setup. With electronics getting cheaper and smaller, it is only a matter of time. Or perhaps, as an engineer, I just like to keep trying out the latest high-tech toys...
I have some Strike Models firing boards on order. I like giving everyone a fair shake. I ordered the "quad" version so as to have all my guns on one board for my QE. Im trying to function in terms of optimum equipment. I will gladly offer my 2 cents when they arrive and are tested. Das Bütts
One thing I have learned from working on switches and school ( I am taking electronics now.. I love punishment) is that switching a boat load of current and TINY will never go hand in hand, never. I am working on a switch now that will be small and switch a large amount of current BUT it will require major heat-sinking and thus no longer tiny. I dont really see a good reason to run a 10a or 20a switch for a solenoid, you get no benefit from it (that I am aware of). My Kip solenoids use 7 watts each so thats only 1.06amps with my 6.6v lifepo4 packs. I could run a triple turret with Kips off a 6 amp switch @6.6v (2.2 amp load on a switch that can handle 4amp sustain, 6amp p> Variable voltage input would be nice but costs more. As far as the adjustable end points, I have never had them and never needed them once I found the right resistors for my push buttons. I would be interested to see what benefits I could get from having adjustable end points. With that said adjustable on a scale would mean a potentiometer which you cant really waterproof. You could use jumpers but then the size goes up and it would be in increments not a fully adjustable scale. I have no idea how much the firing boards cost from Strike as I didnt see them on the web site. I didnt think 20 bucks was bad for a dual switch, its cheaper than the pololu (2 board) setup at the same/near amperage and cheaper than two hansen boards. To me cheap is relative to the market, there comes a point where the cost just cant drop anymore, so you have some that are less expensive than others. I wish you luck in the search and look forward to hearing about all the different switches you guys are trying out. I still plan to make a hansen switch from scratch .. when I get time. J
To chip in ... Personally, I do not like the idea of putting multiple switches on a single board. If the board goes out, then everything is out. At least if I have a switch die it only takes out one cannon instead of all of them (or the pump if it is included). To date, the Turnigy switch meets my criteria: A small, robust (10amps), very low cost (less than $7 each) switch. Admittedly, the Turnigy switch cannot be ganged on a single channel for independent cannon control. But that is not a problem for me due to using an extra channel and transmitter mixing to get the same effect. The very low cost more than outweighs any quirks the Turnigy has.
That makes a lot of sense. I wanted a dual switch to eliminate clutter, y harness, and dip switches. I also like very small and the turnigy would probably be an ideal switch to control my pump relay as all I need is a single switch to trigger the 1 amp relay. I have found that with the dual boards I have that a single switch can burn out and the other still works.. but of course if the microcontroller goes out then the board is dead. Same for any board really. As for 10 amps I don't have anything in my ship that requires 10 amps.. its either 1 amp per solenoid or 30 amps for the pump .. but I use a relay for the pump so the amperage of the switch is irrelevant now. Now if I ran 4 solenoids.. then we would need 10 amps.. but I dont think I have to worry about that. Hahaha J
