Electric Rain
New Member
Alright, so I'm designing my own remote-controlled motorized cable cam (I'm going into videography, but that's a different story...). I need to be able to control the speed AND DIRECTION of two motors (for traveling along the cable and for panning the camera). A circuit like this should suffice, I think. I will split it at the MOSFET. So, the output of U1b would feed to my RF encoder on my "remote control", and the MOSFET would be attached to the output of the decoder on the receiving end. The pulse should actually just transfer right over via RF, (right?) then the MOSFET should amplify it, and drive the motor. I planned on using these ICs for the encoding/decoding.
I don't yet know enough to understand the full theory of this circuit, though I'm sure it's very simple for most of you. So, here's the real question. This circuit uses a variable voltage divider (VR1) to adjust the pulse rates. I basically need TWO copies of this circuit, but controlled by one potentiometer, with a middle deadzone. (I need to be able to reverse the direction of the motor, and I was going to use two separate channels on my RF encoder to specify which direction the motor was actually supposed to run in.) I need to basically "split" the potentiometer. When it's at its mid-point, I want the circuit to be off, and it needs a small deadzone in that area so it doesn't have to be at an EXACT position to be off. When it's turned one way, it should control one of the circuits, varying it from 0% to 100%. When it's turned the OTHER way, it should do the same for the other circuit with the midpoint being 0% for both circuits, and the two endpoints (full resistance and no resistance) being 100%.
So, to clarify, imagine this: The pot starts out in the middle, and the unit is off. I turn the pot clockwise, and the cable cam begins traveling down the cable one way. The more I turn the pot, the faster it travels down the cable. Once the pot is turned to its clockwise limit, the cable cam will be traveling at its max speed. When I turn the pot back counter-clockwise, the cable cam will start to decrease in speed. Once I reach the middle again (remember I need a small "deadzone here), the unit will be off. As I continue rotating counter-clockwise, the other circuit will kick in, sending the pulse to a different input of the RF encoder chip, telling the motor to run in the reverse direction. The more I turn it counter-clockwise, the faster the unit will travel in the opposite direction. At the pot's counter-clockwise limit, the unit will be traveling in the opposite direction as the first time, and at max speed, just like if worked in the other half of the pot.
I REALLY over explained that, I think. I'm sure you guys understood what I needed without that entire previous paragraph, but I just wanted to make sure I was clear. It wouldn't be the first time I tried to explain something to someone that they couldn't understand, but that was obvious in my mind. It's usually due to the way I explain things... I guess.
I'm a programmer before I am an electronic engineer, so it might seem like a simple IF THEN math operation to me at first, but I know it's more complicated with analog hardware.
So, how about it... can someone help me out?
I don't yet know enough to understand the full theory of this circuit, though I'm sure it's very simple for most of you. So, here's the real question. This circuit uses a variable voltage divider (VR1) to adjust the pulse rates. I basically need TWO copies of this circuit, but controlled by one potentiometer, with a middle deadzone. (I need to be able to reverse the direction of the motor, and I was going to use two separate channels on my RF encoder to specify which direction the motor was actually supposed to run in.) I need to basically "split" the potentiometer. When it's at its mid-point, I want the circuit to be off, and it needs a small deadzone in that area so it doesn't have to be at an EXACT position to be off. When it's turned one way, it should control one of the circuits, varying it from 0% to 100%. When it's turned the OTHER way, it should do the same for the other circuit with the midpoint being 0% for both circuits, and the two endpoints (full resistance and no resistance) being 100%.
So, to clarify, imagine this: The pot starts out in the middle, and the unit is off. I turn the pot clockwise, and the cable cam begins traveling down the cable one way. The more I turn the pot, the faster it travels down the cable. Once the pot is turned to its clockwise limit, the cable cam will be traveling at its max speed. When I turn the pot back counter-clockwise, the cable cam will start to decrease in speed. Once I reach the middle again (remember I need a small "deadzone here), the unit will be off. As I continue rotating counter-clockwise, the other circuit will kick in, sending the pulse to a different input of the RF encoder chip, telling the motor to run in the reverse direction. The more I turn it counter-clockwise, the faster the unit will travel in the opposite direction. At the pot's counter-clockwise limit, the unit will be traveling in the opposite direction as the first time, and at max speed, just like if worked in the other half of the pot.
I REALLY over explained that, I think. I'm sure you guys understood what I needed without that entire previous paragraph, but I just wanted to make sure I was clear. It wouldn't be the first time I tried to explain something to someone that they couldn't understand, but that was obvious in my mind. It's usually due to the way I explain things... I guess.
I'm a programmer before I am an electronic engineer, so it might seem like a simple IF THEN math operation to me at first, but I know it's more complicated with analog hardware.
So, how about it... can someone help me out?