flip flop for driving latching solenoids

[kitcat]

Hi.
I need to drive 16 latching solenoids.They all have a common feed and an individual return and by reversing the polarity I can latch or unlatch them.
I guess I have to send a positive pulse to all the ones I want to latch and then a negative pulse to all the ones I want to unlatch. I guess that one way of doing it is to have a relay switch the polarity driven by an output pin on a pic and then some sort of drive circuit for the individula lines to the solenoids. I am struggling to find an elegant solution for this. I started down the uln8203 route until I discovered they needed their polarity reversed. I want to try to avoid having to use loads of mechanical relays. can someone show me a neat solution.
Thanks

[mister_e]

Something like an H-Bridge driver... well something like the append.

If your solenoids are not too current hungry, you'll find a load of h-bridge driver in a single IC. Really handy.

BUT, there's a BUT, if you don't need to send always voltage to your Solenoids, the append(without the inverter but 2 i/o on your PIC... ) will do the Job

[kitcat]

HI. Thanks for that.
I have been investigating a bit further. I am basically trying to get an old weaving loom working. It has a controller for the "shafts" which latch with the solenoids. It has a Z80a on board controller. I examined the drive ciruitry and have drawn (probably badly but I think correctly) the schematic for the bit that controls the solenoids (and therefore the latches).
Each output to the latches comes in two parts. The first is a global pulse to all the solenoids so they are all in an unlatched state. Then immediately after that there is a pulse to all the solenoids that need latching, presumably by the transistors. (bc182). There are two relays that must reverse the polarity for both pulses.
Can anyone suggest a good way to proceed. Is there a more modern solution? I still have my uln8203s for driving the solneoids in one direction. I think it would be too difficult to try to use the existing drive card.
I think the point is that when a shaft is latched and the loom treddled, that shaft has to be unlatched for the next treddle otherwise one would be unweaving the thread. That is probably why a global unlatch is sent each time.

[AMay]

I spent some time trying to think of a neat way to control modern latching relays, and gave up.

But it is very easy to make a latching relay out of a PIC. Send the output to a 2N7000 Mosfet (no resistor required) to control an ordinary relay. It will source 200ma or more.