Hi help with simple dc 12 volt toy motor control

mikediv

Hi guys I love this forum lots of smart people , I am brand new to the prop and was wondering I have a few toy 12 volt dc motors
I wanted to interface one to the prop ed board and be able to control it speed it up or slow it down but the hard part is I want to display the RPM or voltage as it speeds up or slows down is there anyone that has somehting like this I can look at for idea software/hardware, I did it with a basic stamp but this is a whole new ball game thanks I also have the hydra board if that would be easier to use
Oh and maybe one quick question I bought the add ons for the prop educational board I have the prop project parts kit #130-32000
there is a round part in the bag and it has a sticker on it its round the size of a dime and the sticker says wash before removing does anyone know what the heck it is?
·

Andrew E Mileski

The motor's commutator causes a pulse whenever it breaks contact. These pulses can be monitored on the power leads, though one needs to know how many poles the motor has to use as a divisor for a full revolution.

For example, this is used in the Microchip TC670 Fan Alert Monitor, as well as brushless motor controllers (though they also have to figure out motor direction).

Something to Google on or start with at least

GeorgeCollins

I have had good luck with hobby motor controllers such as:

http://www.servocity.com/html/c-7_speed_control.html

(although this one might not be able to handle as much power as you want, you can find a huge range available)

The prop proto board-- and many other boards have a plug set up for a servo. As long as you have a 5v supply, you can control hobby speed controllers just like a servo, by varying the pulse width.

mikediv

Thanks guys I orderd the prop proto board I only have the hydra and the educational kit propstick I have a few parallax servos just want to try and control the cheapy dc motor I have quite a few og them walmart was selling this hand fans fora dollar they came with 2 batteries energizers and cheap plastic fan a a little dc motor I couldnt buy 2 AA batteries for a dollar so I bought like 20 of the things the motors are really small and work down to 1 volt I can turn it on and off with the prop just seeting the I/O and sending an output 1 to say P0 but that all I can do turn it on and off like an LED I took at look at the lines with my scope to be honest there is not much noise looks pretty clean how would I read pulses from it they do have brushes and the armeture has 2 poles ??? thanks for any help guys

evans

Hi Mike,

I too was confused by the part that begged to be thrown in the washing machine.· When I pulled off the sticker and saw the hole, I realized I was looking at a piezo-electric speaker.· (I HAD to pull off the sticker, kinda like mattress tags, you know?)

mikediv

evans LMAO I got brave and pulled the sticker and figured it was the pizzo lol why does it want to be washed though?
·

evans

I think the folks at Parallax got a good deal on something printed for an entirely different use, but Parallax realized they would fit perfectly over the hole to keep trash out during shipping. It's a small detail, but that type of "outside the box" thinking is why they have done so well with the propeller.

I'm thinking the person who came up with this also has a sense of humor almost as warped as mine...