The NEW Build Your Own Arcade Controls
Main => Main Forum => Topic started by: doctormord on November 17, 2011, 05:16:05 pm
-
Hi everyone,
at first let me introduce myself. My name's Chris from Germany, i'm a teammember of modcontrol.com-staff since several years. Actually i'm studiing microsystemelectronics..
To make it short, i'd read a thread here in this forum which belonged (surprisingly) to an arcadecab-conversation with an xbox360 and the wireless racing wheel. As far as i know, there actually is no force-feedback-hack for this wheel.
I thought about doing this some month ago, using an 18v-power-driller-motor in the wheel. Beside the mechanical problem with the pinion there was also a big problem to spin the motor.
Hooked up the scope showed some nice pwm-stuff for the build-in controller. (45kHz 0-50% duty)
So what we have in there?
Signals:
Direction (L1): Low/High
Enable: PWM Low/High
What we need for a "standard" motor-controller?
Direction (L1/L2): Low/High x2
Enable: PWM Low/High
The (other) main-problem is the pulse-length for the motor to spin. The power-driller-motor needs longer pulses to spin up and produce torque. So stretching the Enable-PWM is needed.
All in all i actually ended up with an L6203 Full-Bridge-Motor-Driver, 5 Inverters and some capacitors/resistors to make things work.
Hooked up the whole thing to the new motor resulting in ~8amp stall-current at 18V, where ~39watts are "heated away" in the bridge (2x RDSon = 0.6ohms) and ~100watts puts power to the wheel. :D
Controller needs to be cooled, as well as the motor.
All in all, the L6203 solution is not the best, because of the high MOSFET-RDSon losses (IČR) and there's also no currentlimit at the moment...
But alot of fun!!
See some pictures attached, the first four shows circuit/wires, the next three shows simulation results for the pulse-stretcher.
-
Continued here:
Attached are some scope-probes from the real circuit showing the pulse-stretch-signals. (Yellow original, Blue modified)
Settings:
Analog Ch State Scale Position Coupling BW Limit Invert
CH1 On 1.00V/ 0.00uV DC Off Off
CH2 On 2.00V/ -6.00V DC Off Off
Analog Ch Impedance Probe
CH1 1M Ohm 1X
CH2 1M Ohm 1X
Time Time Ref Main Scale Delay
Main Center 5.000us/ 298.6000us
Trigger Source Slope Mode Coupling Level Holdoff
Edge CH1 Rising Auto DC 2.16V 500ns
Acquisition Sampling Memory Depth Sample Rate
Normal Realtime Normal 50.00MSa
All in all it is possible to hock up any motor-driver to this circuit, which is using the "standard 4-quadrant-mode".
Hopefully this is somewhat helpful (and please excuse my english). I'll post some shematics when final circuit is avail.
For now, 2 videos showing the thing in action. One-hand-driving is not recommend.. :lol
http://youtu.be/A8oqMpy8wuo (http://youtu.be/A8oqMpy8wuo)
http://youtu.be/4tE75vDZlA4 (http://youtu.be/4tE75vDZlA4)
Cheers doc
-
Hi all,
next step is the interface pcb with current-limit-chopper.
Cheers, doc.
-
Hi doctormod.
I joined this forum after finding this thread. Excellent work!
I'm looking at doing something simmilar and have a thread of my own on xbox-scene.com:
http://forums.xbox-scene.com/index.php?showtopic=743154&st=30 (http://forums.xbox-scene.com/index.php?showtopic=743154&st=30)
I'm interested to find out more about the way you did it. Also I would appreciate it if you could have a look at what I have worked out so far and let me know what you think.
:)