A stepper motor controller usually use a microcontroller to make a complicated task. Some controller use stepper motor ic to simplify the circuit design. For simple task like just rotating with constant speed a simple controller circuit can be built using discrete components.
Here is the schematic diagram of the circuit:. And so if the pot is adjusted to increase the resistance in the branch the frequency of clock decreases. Now the decade binary counter counts the number of pulses fed at the clock and lets the corresponding pin output go high. For example if the event count is 2 then Q1 pin of counter will be high and if 6 is count the pin Q5 will be high.
This is similar to binary counter however the counting will be in decimal ie. These outputs are fed to transistor to drive the stepper motor in orderly way. In figure we are seeing a four stage stepper motor driver circuit very similar to the two stage one.
In this circuit, it can be observed that the RESET connected to Q2 before is now moved to Q4 and the opened Q2 and Q3 pins are connected to another two transistors to get a four pulse driving set to run the four stage stepper motor. So it is clear that we can drive up to ten stage stepper motor. The diodes placed here are to protect the transistors from inductive spiking of the stepper motor winding. If these are not placed one might risk blowing the transistors.
Greater the frequency of pulses,greater the chance of blow up without diodes. For better understanding of step rotation of stepper motor we are considering a four stage stepper motor as shown in figure. Now consider, for an example, all coils are magnetized at a time. The rotor experiences forces of equal magnitude from all around it and so it does not move. Because all are of equal magnitude and are expressing opposite direction. So the rotor moves to complete a step.
After that it stops for the next coil to energize to complete next step. This goes on until the four steps are complete. For the rotor to rotate this cycle of pulsing must be going on. As explained before, the preset is set to a value for a certain frequency of pulses. This clock is fed to the decade counter to get regular outputs from it. The outputs from decade counter are given to transistors to drive the high power coils of stepper motor in sequential order.
No reading schematic to translate what is written on board to what pin it actually goes to. Reading the datasheet and looking over any available examples often prevents the 'venting of the magic smoke' Thank you Mike Reading the datasheet really does not help me much. Found a plain talk common sense article on 'L Connecting a different micro to DC motor'.
Has nice explanation of H bridge. After all these years of seeing 'H bridge'. All set! I will look up Parallax H bridge. I think they had some leftover motor driver boards or parts that were around for awhile. The real deal is a simple one or two motor H bridge board. Will see if there was one. I never liked that one that looked like a little cube. Didn't look right to me. Here's a Parallax board that looks okay. The Wikipedia is a great source for 'common sense' explanations of many things including H-bridges.
That is absolutely essential information not only for any IC but also any driver module that you want to use. Reading datasheets and supplied documentation are part of building circuits. You will make 'magic smoke' from time to time. That's also part of building circuits. Check your connections with a meter before you apply power.
Larry If the grass is greener on the other side The 1st uses the same diagram from StampWorks and the 2nd shows the connections directly to the chip. The LD is such a common chip that a decent electronic supplier will have it in stock. Oh, and while looking for your diagrams, I saw that someone in an Arduino forum noted that the LD will drop as much as 2 Volts so you need to add 2V to what the motors need.
To get a position control that are low cost, accurate and simple we can use stepper motor. To drive it we can use a circuit mounted close to the motor, and to control it we can use remote control circuit via long cable. The power for both motor and the driver circuit is carried over two wires the same wires that carry the control signal.
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