Ok, This One Is Strange. I need A Flip-Dot Driver Circuit

Do you have a handful of individual cells that are 1 dot each with 2 wires coming out? Or do you have a module with lots of dots and a few wires coming out?

If the latter, the unit probably includes the drivers and you talk to it with RS-232 or similar.

If you have a handful of individual dots, you need to figure out how much current they take and what voltage. You can probably experiment with a battery and resistors.

If you want more than a single dot, I'd expect the simple way to go is to put them in a matrix. You have horizontal and vertical wires. Put a dot at each intersection and connect one lead from the dot to the horizontal wire and the other to the vertical wire.

Then you need 2 drivers for each wire. One pulls up. The other pulls down. If neither is on the wire floats. You can probably get that with a transistor and resistor for each driver if the current is low enough.

Do set a dot, you pull up on one wire and down on the other of the pair that intersects at the dot. To unset it, reverse up and down.

Actually these units were in a display for a toll booth. I intended to take the matrixes apart to make individual segments out of them. So the end display would be like a big LED one, only with a bank of 7 flip dots for each segment. The displays are currently in a 5x7 matrix on boards, but I can easily break up the matrix to make my segments out of.

The actual 1x7 elements are BUSE BM-70. I did have the power requirements at one time. I seem to recall I figured it out to be 5 v at at about 100 ma or so. I guess my problem is how to get the lines to reverse polarity using TTL logic.

I have a score keeper that I built using hi-brite LEDs, but they are not bright enough for sunny day use, so I figured I could put these elements in instead.

Thanks,

- Tim -

Tim wrote in news:MPG.209c7c9814af1ce989760 @allnews.nbnet.nb.ca:

TTL

one

reverse

You want an H-bridge. They are commonly used to control DC motors with logic signals. If not much current is needed, you might be able directly drive them with the right buffer IC.

Yup I remember that 4 transistor setup from before. I found a bunch of references on the net about that, so I'll do some digging for a bit..

Thanks for the info.....

- Tim -

Hi again, I think I have found a solution using your information. I came across a chip made by Maxim the MAX4424 series. I also found real world circuits using this unit to drive DC motors. I have asked for some samples to see if they will works with my application, but I have to wait for "factory approval" for them to ship. I am expecting a very high failure rate while I am getting the mix down just right.

If this works out, I will use 1 chip, 2 resistors and maybe 4 diodes per segment of my display. I will need quite a few of them, but I can buy them in small amounts until I have enough.

Thanks for your help in getting me started...

- Tim -