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jwatte
04-28-2014, 11:39 PM
The boards are back from the factory! Of course, I immediately found a firmware bug, so I now have to re-flash a hundred boards. I guess I can pay the kids a quarter per board... and pass the cost on to you all! Ha! :-)

So, before these boards become available on Amazon (which is soon,) you might want to read the manual to figure out whether you really want one of these or not. Or two. If you want to do that, I'd love to hear your feedback on all my misspellings, poor phrasing, and general authorship ineptitude, all for the betterment of those who come after.

http://onyxrobots.com/2014/04/29/onyx-fire-ii-manual/

ArduTank
04-29-2014, 05:57 AM
What you selling them for? And what's the rated amperage??

Xevel
04-29-2014, 07:16 AM
And what's the rated amperage??

Have a look at the documentation (http://onyxrobots.com/wp-content/uploads/2014/04/Onyx-Fire-II-Manual1.pdf) ;)

@jwatte: First thing I noticed on your document: there's no page numbers :/
It looks very thorough , but I'll read the thing before saying anything else.

jwatte
04-29-2014, 12:26 PM
The manual (and, soon, Amazon product listing) says 8-18V, 20A peak draw, 5A average draw. The main limiting factor is heat dissipation from the copper on the board, which is in many ways an estimation crap-shoot, so they can quite likely be pushed harder than that in many cases, if you're okay with the warranty being void in case it doesn't work :)

I've run the Double Eagle AEG on continuous action from a 3S LiPo with 50% PWM duty cycle, and I believe it can do this indefinitely.

Amazon Prime price will be $39 including the connection cable. I will sell them at "show special" prices if there's ever another MW competition (ahem...)

jwatte
04-29-2014, 12:33 PM
@jwatte: First thing I noticed on your document: there's no page numbers :/


Oh, duh!
Fixed :-)
http://onyxrobots.com/2014/04/29/onyx-fire-ii-manual/

Deimos
04-29-2014, 05:16 PM
Looks very thorough, nice job!

One thing you may wish to clarify: On page 4 (in the table) minimum input voltage is specified as 7V, but on page 6 (paragraph 1) it says:

The Onyx Fire II board can plug right into an existing Dynamixel TTL based serial bus for power and
communications, as long as the supplied power is between 8V and 18V...
Since I intend to power my gun with a 7.4 Lipo, the minimum input voltage is somewhat important.

jwatte
04-29-2014, 05:40 PM
7V is the lower end of what will work. 2S LiPo will work fine as long as they're not discharged below 7V.

The main problem I found with under-voltage when trying different levels is that the 7805 regulator I'm using has almost 2V drop-out, and when the AEG motor kicks in, it may draw enough current that it lowers the voltage provided to the board, at which point under-voltage protection on the MCU kicks in, and locks everything up. If your batteries are high-C and not depleted, it will likely work fine!

I want to post a blog post on the onyxrobots.com site with actual measurements and videos about this if I can find the time.

byi
04-29-2014, 06:10 PM
Looks great! Will the sensors be available as well?

jwatte
04-29-2014, 10:13 PM
I have a working board from OSH Park, and it conveniently fits into a groove I made in the Shapeways mounting parts. I will solder up a few myself, and make some cables for them using pre-crimped wiring, but I expect some cost-conscious hobbyists might roll their own :-)
Amazon sales/shipping overhead really hurts. It adds like $10 to anything you want to sell. On the other hand, it then takes care of all ordering/shipping/customer service, so I guess that's worth something. And those who have Prime get free second-day shipping.

byi
04-30-2014, 09:41 AM
Hmm, ok. Any switch that opens then closes again (or reverse) when fired would work?

jwatte
04-30-2014, 03:03 PM
Any switch that opens then closes again (or reverse) when fired would work?

Yup! But don't tell the Internet I said that ;-)

byi
05-01-2014, 01:27 PM
Yup! But don't tell the Internet I said that ;-) Ok great. Wait, so should it go off-on-off or on-off-on? Just need to figure out where to put the contactors.

jwatte
05-01-2014, 01:39 PM
The cycle is considered "complete" when the contact closes (pulls the sensor pin to the ground pin.) This is how opto detectors work -- when the slide is at the far front, the opto sensor activates and closes the circuit, which counts "one cycle" in the activation control. The activation control lets you specify some number of cycles, with some timeout if the cycle counter is not attached or fails.

Now, each board is supposed to come with a red two-pin header jumper, and I only had a handful left in the toolbox, so right now I'm just waiting for my order of those to arrive so I can drop them into the box before I mail them off... it's the little things :-)

byi
05-01-2014, 01:58 PM
The cycle is considered "complete" when the contact closes (pulls the sensor pin to the ground pin.) This is how opto detectors work -- when the slide is at the far front, the opto sensor activates and closes the circuit, which counts "one cycle" in the activation control. The activation control lets you specify some number of cycles, with some timeout if the cycle counter is not attached or fails.

Now, each board is supposed to come with a red two-pin header jumper, and I only had a handful left in the toolbox, so right now I'm just waiting for my order of those to arrive so I can drop them into the box before I mail them off... it's the little things :-)

Ok. Thanks for the help. sorry to take three posts t ask one question.