Salut
We are in Dakar, Sénégal, for the second PD/XXXduino workshop in west Africa where we prototype a suitcase for the pedagogy of interactive art.(( http://www.craslab.org/valise (draft, english soon)))
We try to find a solution to control the stepper motor and dc motor with PD standard firmata 2.1 with the adafruitmotorshield. Servomotors are easy to pilot from PD, but steppers and DC motor are piloted by a chip. The docs says (http://www.ladyada.net/make/mshield/faq.html):
"The DC/Stepper motors are NOT connected to the Arduino directly. They are connected to the 74HC595 latch which is spoken to by the Arduino. You CANNOT talk directly to the motors, you MUST use the motor shield library"
Does anyone in the list has found a hack to talk to this chip from PD to pilot the steppers and DC motors ? Thanks JNM, Jérôme Abel, and 17 Senegalese and Malian students
All you need to drive a DC motor is simply some kind of transistor. The Arduino cannot provide enough current, that is all. With stepper motors, it's a bit more complicated since there is a forward and a reverse pulse. Also, if you want to be able to change the direction of the DC motor, then you will need to use some sort of H-Bridge IC to switch the direction of the DC current. IIRC, the H-Bridge simply take High or Low to one pin to switch the current from positive-flowing to negative-flowing. If you only want one direction for your stepper, you could try just sending PWM via a transistor to one leg of the stepper and see what happens ;-)
I'm sure others have less Neanderthal suggestions, but these could get your started.
D.
JNM wrote:
Salut
We are in Dakar, Sénégal, for the second PD/XXXduino workshop in west Africa where we prototype a suitcase for the pedagogy of interactive art.(( http://www.craslab.org/valise (draft, english soon)))
We try to find a solution to control the stepper motor and dc motor with PD standard firmata 2.1 with the adafruitmotorshield. Servomotors are easy to pilot from PD, but steppers and DC motor are piloted by a chip. The docs says (http://www.ladyada.net/make/mshield/faq.html):
"The DC/Stepper motors are NOT connected to the Arduino directly. They are connected to the 74HC595 latch which is spoken to by the Arduino. You CANNOT talk directly to the motors, you MUST use the motor shield library"
Does anyone in the list has found a hack to talk to this chip from PD to pilot the steppers and DC motors ? Thanks JNM, Jérôme Abel, and 17 Senegalese and Malian students
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Derek Holzer -
JNM