Fez Hydra, ESc and LiPo batteries


Given a battery such as this one http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=8852, some ESCs like these http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=2163 and a Power Distribution Board like this one http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=23140, I want to start making a quadcopter.

I have the Hydra and all the other required bits. the motors are these http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=5689 but it’s irrelevant.

My question:

  1. Hardware - How do I setup the battery so it supplies both the power distribution board and the USB Client DP Module (on the power jack, of course)?
  2. Software - How do I control the motors? Which driver should I use, codewise?

I looked for the answers and the only rhing I found is this Software & Sawdust: Controlling a Brushless Motor with NETMF, which has some questions still unanswered.


IanLee74’s blog post that you linked to points towards driver code, here: http://www.tinyclr.com/codeshare/entry/36 and TimC has some notes on the required boot sequence for getting the Hobby King ESC working here: http://www.tinyclr.com/forum/topic?id=5644

I can’t help noticing though that the Hydra board only looks to have 3 PWM pins, aren’t you going to need at least one per rotor? Spider’s got 6 PWM pins, Cerberus I think will have 9 though it’s still in development - much smaller, lighter and cheaper too, so when finished should make a much better UAV pilot.

Add IO60P16 module and you will have 16 PWM pins, add two and you will have 32 PWM pins. Need more? Add more modules :slight_smile:

RorschachUK, Gus - Thanks a miliion.

The driver is from 2010… Is this good enough? Seems real simple. Then again, simple is beautiful.

Thansk for the inputs. Will look in the Fez forums moreover.

Concerning the additional PWM - indeed. Already ordered one. Is there any way to extend other modules? like I, X, P and U? IS here any way to add some type of extender that adds other connection types, that are not currently on the Hydra?


The driver may be from 2010, but it’s essentially just encapsulating PWM at heart. No matter what ‘nice’ libraries these various components get wrapped in, they mostly all boil down to a handful of basics - ‘bitbanging’ digital IO, PWM, analogue voltage readings, serial UART etc - and when you’re dealing with any hardware that isn’t explicitly packaged as a Gadgeteer module, such as your speed controller, it’s always going to come down to which of those basic methods to use (PWM in this case), plus maybe some essential operational parameters. Here for instance it looks like the ESC is picky about the range of speed values it likes, so the driver encapsulates some protections to prevent you from accidentally exceeding them. I don’t know what happens if you do exceed the safe values, but I imagine it’s somewhere on the sliding scale between burning out your motor, through losing an eye, all the way up to tearing a hole in space/time, and I wouldn’t be keen to have to discover where along that line the truth lies. The ‘proper’ gadgeteer module drivers are open source, if you look inside them they’re all just adding a layer of event-driven, object-oriented, design-surface-friendly convenience over essentially the same small subset of basics over and over, so a 2010 NETMF driver should still work even if it doesn’t give you a nice pictured ‘brushless motor’ component to drag and drop onto the Gadgeteer design window - doesn’t matter, you could still program each and every one of the ‘proper’ Gadgeteer modules by declaring them to be an Extender module on the design surface and handling the hardware communication at a lower level, just as you’ll be doing when setting rotor speeds for your quadcopter. I think Gadgeteer is a great idea - I’d rather be writing C# with intellisense than just C/C++, and I’d rather be just plugging stuff together without having to worry about circuit design, breadboards, or soldering - but it’s still worth a peep over the walls of the beautiful garden Gadgeteer gives us, to see that the world beyond isn’t so scary really and the horizons are a lot broader than the gadgeteer module catalogues might suggest.

RorschachUK - what a great answer. What a great insight. FTW.

I hope you take it in the most a-sexual way possible - I think I am in love with you.

…and that’s why you should NEVER inhale the fumes from solder flux!