I am in the process of designing a project that will allow a Raspberry Pi to "print" to an old (60s) electric typewriter. I have decided to have a push-solenoid for each key (24V), for 48 total keys. I have chosen a set of decoders (74VHC138M) to take a six-bit output from the RasPi GPIO pins to select the solenoids (one at a time).
I am trying to figure out how to drive the solenoids, and I think an optocoupler might be a good idea (something like this: LTV-847).
My question: can I drive the solenoid straight through the LTV-847 simply by triggering the optocoupler with the decoder? I was looking at this post and I'm wondering if will be necessary to build a Darlington (one for each of the 48 keys...). I'm hoping I don't have to do that, but if it necessary, I want to do it correctly.