Speed of Optos on BoBs

[boldford]

This is the BoB I've been referring to. (I said it was a simple design).

The plan now is to either obtain some 150R 1206 SMT resistors to mount on top of the existing 1K ones or simply replace them with 120R. With this mod applied tests indicate the O/P voltage swing will now only be approximately 3.5V. This suggests the next step will require a veroboard hack to introduce 74LS14s on all channels ensuring the I/P and O/P isolation isn't compromised.