induction wrote
The simplest thing to do would be to feed the output of one circuit to the input of the other, just as if they were in two separate boxes, except the connection between them is hardwired. It should be very easy to do, but let me know if you need more detailed instructions.
That's just what I did, one board with a short brick and one with a long brick in the same enclosure.
Originally had the opamp IC in backwards and started cooking components but then my nine year old diagnosed and fixed the problem.
Sounds great! Thanks much for the circuit, induction!