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CP44
Trainee




PostPosted: Tue Sep 28, 2010 10:52 pm View user's profile Reply with quote Send private message

I've hung around #Descent3 on GameSurge hoping to find Grendel or another (un)lucky hardware engineer to ask about this... =)

I have next to me a Teensy 2 board and a box full of nerd trinkets & tools. I've noticed the 3DP-Vert project and some other attempts to use the Teensy as an HID class game device, and I have wanted something that can handle digital and analog signals as gaming device inputs like the Beta Innovations Plasma cards used to.

Since I'm currently unemployed and living in a confined area, I've got a laptop running, no D3-worthy flight controls, a small amount of money to experiment with, and some time (since places I apply to aren't quick to call me back). I want to get into raw/custom interface devices as a way to get some hardware experience and have some fun.

I also have a 50K pot (potentiometer), a 100K pot, a desire for linear pots, and a theory on how to make foot controls easier to implement without heavy pedal sets. Wink

I am wondering if Grendel, Koolbear, Sickone, or any of the others have tips for getting into this from scratch...
where to get parts, what to do, what not to do, etc.
(like the obvious "do not insert 115V AC into the VCC path")

Specifically to start:
1. One of my ideas will likely require decision logic at the device level... What's the easiest way to program the Teensy to be an HID gaming device while allowing full access to the internal ADC, pull-up resistors, and report format?
2. I noticed Grendel saying something about Windows being tricky with polling rates - anything I should know?
3. I've seen something hinting at 10K for Teensy boards. Is there a certain potentiometer resistance I should use if given the choice?
4. I found out about Celesco potentiometers, and we used them for a full ultralight simulator; but I fear they’re industrial-quality expensive (prices not shown online, waiting on email). Any recommended provider(s) of such things as "cheap potentiometers", linear and/or rotary?

5. A possibly intrusive notion: I am not familiar with the Microsoft pinouts or methods nor the true functionality of 3DP-Vert, but if not all of the Teensy pins are used by the gameport project, have the remaining pins been marked as generic to make them generic buttons/axes by just wiring to them? If not, I would be highly interested in a fully generic firmware set that would benefit the flightsim community (for sure) as well as maybe Descent pilots, racers, and others who have extra controls or button panels. (...even if I have to set it up myself, which is why I'm here... to do it right, hehe.)

All responses and ideas welcome, and if anyone finds my experiments/findings/results educational (or humorous) I can keep this up and post pictures. (On the other side, sorry & let me know if this is waaaay oddball.)

--John/CP44
(an ancient NuB and a hardware n00b)
Grendel
Ninja Admin




PostPosted: Tue Sep 28, 2010 11:43 pm View user's profile Reply with quote Send private message

CP44 wrote:
I've hung around #Descent3 on GameSurge hoping to find Grendel or another (un)lucky hardware engineer to ask about this... =)

Heh, I don't go there very often anymore...

Some answers:

CP44 wrote:
I am wondering if Grendel, Koolbear, Sickone, or any of the others have tips for getting into this from scratch...
where to get parts, what to do, what not to do, etc.
(like the obvious "do not insert 115V AC into the VCC path")

Not really unfortunately. It took me writing two fully featured USB device implementations for real world applications to fully understand Chapter 9, HID, CDC, and Vendor classes :/

Step one would be to get the USB 2.0 and HID specs:

http://www.usb.org/developers/docs/usb_20_081810.zip
http://www.usb.org/developers/hidpage/

Step two is probably to find implementations, the 3DP-Vert code is here, Atmel has some more complete implementations but caveat -- they are examples and thus bug ridden and not fully tested :/

CP44 wrote:
1. One of my ideas will likely require decision logic at the device level... What's the easiest way to program the Teensy to be an HID gaming device while allowing full access to the internal ADC, pull-up resistors, and report format?

The 3DP-Vert code could be used for that.

CP44 wrote:
2. I noticed Grendel saying something about Windows being tricky with polling rates - anything I should know?

Windows will not change the poll rate if the SET/GET IDLE requests aren't implemented.

CP44 wrote:
3. I've seen something hinting at 10K for Teensy boards. Is there a certain potentiometer resistance I should use if given the choice?

10k to 100k linear will do just fine.

CP44 wrote:
5. A possibly intrusive notion: I am not familiar with the Microsoft pinouts or methods nor the true functionality of 3DP-Vert, but if not all of the Teensy pins are used by the gameport project, have the remaining pins been marked as generic to make them generic buttons/axes by just wiring to them?

All unused pins are configured tri-stated IIRC and you can do whatever you want w/ them Smile

_________________
Borders? I have never seen one. But I have heard they exist in the minds of some people. -- Thor Heyerdahl
Durch einen Stich bereits geschafft, erschlafft und ohne Saft und Kraft! -- Donald, examining a Deflator Dextrospirillus
Grendel
Ninja Admin




PostPosted: Wed Sep 29, 2010 2:04 pm View user's profile Reply with quote Send private message

Forgot USB in a nutshell. Read that 1st for an overview about how USB works.

_________________
Borders? I have never seen one. But I have heard they exist in the minds of some people. -- Thor Heyerdahl
Durch einen Stich bereits geschafft, erschlafft und ohne Saft und Kraft! -- Donald, examining a Deflator Dextrospirillus
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