12VDC Brushed DC Motor

[Drools]

What is the easiest simplest method to control the speed of this type of motor with PWM. I'm thinking of using 1/2 of an H-Bridge?
I want my uC to control the speed using PWM but not sure if I should use transistors or a chip. A circuit diagram would be nice.
Thanks

[Al_The_Man]

Any of the Semi manuf will have circuits in their AP notes, Freescale, IR, Allegro, etc.
Also the PicMicro site has a few Motor Control Design Center
Al.

[RomanLini]

Well you did say "the simplest easiest way" so I think for a PWM controller that would be one of the "DC motor speed controller" kits available from all the hobby electronics outlets.

You could also check out "battery powered scooter speed controller" those are often available cheap too.

[Drools]

You are right and I was thinking about this one.
Motor Driver 1A Dual TB6612FNG - SparkFun Electronics
It is dual motor controller but I will just use a single output. In the end I want something that someone can make on their own with little soldering experience. My little project will be open source. It would be nice if I can keep the PCB size to within Eagle's demo limitations. So far I have Sparkfun's EasyDriver and now this controller and 5 x 7-segment displays and 1 Atmega48. I guess I could seperate the displays on their own PCB.
Thanks

[Al_The_Man]

Have you checked out the Jameco kits?
e.g.
K8004: VELLEMAN INC.: Education & Hobby
Al.

[Drools]

Thanks for the link Al. The specs on that kit is a little more than I need.
I'm basically using a 12VDC motor to wind wire on a guitar pickup, at 3 speeds.
Lo. Med. hi. The current draw will not be much. It will be geared too.

[Al_The_Man]

I thought is was a rather simple design for uni-directional control?
Are you syncing the wire feed to the DC motor? or just manual control?
Al.

[Drools]

I posted this general description on another forum.
I may need 2 uC.

I'm looking at controlling a small NEMA17 stepper, a 12VDC motor and 5 x 7-segment LED display modules with one Atmega48.
I'm making my own pickup winder as a project and I want make sure I can build it the way I see it.
In program mode I want the m48 to read the number I put into the displays. Most likely in the range of 6k to 10k.
In run mode the m48 will control the stepper with step signal via a Sparkfun EasyDriver as well it will set the speed of the 12VDC motor turning the bobbin.
I would like the LED display to count down as the bobbin motor turns. I will make a simple optical encoder on the motor shaft with just one window.
The stepper will control the wind pattern on the bobbin.
I would like to have 3 speeds, low, med, hi. Pressing a momentary button would cycle the speeds.
There would be one momentary button for program and run mode.
Each 7-segment LED would require one button to increment the value, it would just go to 0 after 9.
I do not have a keypad matrix but I do have a bin full of momentary push button switches.
I may have to add some debounce circuitry/code to the switches.
I was thinking of clocking the m48 at 16 or 20 MHz.
The DC motor I have has an optical wheel mounted to one end which could be used as feedback to the uC or I could just use a set PWM output levels so I achieve the, lo, med and hi speeds.
The steppers speed will need to be synced up to the bobbin speed so the fill pattern on the bobbin is uniform.
I already have the general mechanical outline made, the electronics are next.

[Al_The_Man]

What about setting up a gearing arrangement, if you had a low res encoder on the final shaft, the step pulses could be geared off of this either directly or via the the µprocessor, for various wire diameters etc, so the stepper would automatically follow the set rate of the DC motor.
This is similar to the method used by closed loop CNC controls for geared threading.
A key pad could input the various gear ratio or rate depending on wire gauge.
It should simplify the whole scenario, no?
Al.

[Drools]

Thanks for the reply Al. I’m definitely open to suggestions. I will have to look for an example and see if I can do it this way. The gearing table might be stored in the uC's memory and be selectable with a button.

[RomanLini]

I would just use 2 stepper motors, and you can control the coil winding by exactly controlling the speed of each motor. It also would have a lot more "cool" factor compared to a little DC motor with noisy gearbox.

As an added refinement you could automatically control the coil roating speed and wire position based on what angle the coil is at, since pickup coils are long rectangular shapes that would be very handy.

What system of controlling wire tension are you using?

[Drools]

Oops my mistake, I'm not using a gear-head motor but rather belt/pulley arrangement on the DC motor. I want to slow the DC motor down so I will use a small pulley on the motor and a larger pulley on the bobbin shaft. This all salvaged hardware that did not cost me anything. The only parts I wanted to buy were some of the electronic parts. I might use this device half a dozen times a year, noise is not a factor. I have seen a 2 stepper (NEMA23) version of what I'm doing but it is much more complex design and I figure a DC motor would be simpler.
For the tension, I'm going to thread the wire through a series of V-groove wheels 3 or 4 of them depending on the tension provided, like an over/under arrangement.
In case you are not aware, the gage of wire is AWG42/43 like a thin human hair. The number of turns on the 4.5" bobbin would be 6k to 10k+ depending on the resistance you want.
I could buy one of these machines for 350.00 to 650.00 but I like the challenge of DIY.