Schematics – Question About Roland 606 Schematic

1. Schematic needs part numbers or a BOM attached. eg what type of cap?
2. Card interface needs protection for ESD sensitive devices on interface pins such as MOSFET gates. or a warning label.
3. Relay contacts may need ferrite filters to reduce ingress of signals from sprinkler wires (antennae) and internal electronics. CM ferrite choke recommended.
4. Also contacts can create peak AC transients to be radiated from interface cables to nearby electronics connected to this card.
5. Since these are not zero crossing switched solenoids, it is hard to say if there will be any EMC surge ingress issues at a system level but filtering or shielding may be necessary and use twisted pair wires. Otherwise, contacts may be heard on AM radio which you can use off channel as a quick test. concur with other suggestions.
6. An LED indicator & resistor on board and each driver may be useful. 3mA or so should be adequate with any low cost AlGaAs indicator rated for 20mA.
7. Schematic needs legible notes for interfacing requirements, test points
8. Galavanized nails are highly unreliable for reliable plant moisture sensors but for crude watering, it may be acceptable. Capacitance mode is more reliable than resistive mode for linear thresholds due to drift in soil shrinkage around sensor, galvanic soil offset, AC hum, RF noise etc.. I hope you have done some research.

It is hard to read, but possible.

No, you are not right. AC5 is a pin of the chip. You have to place a 27 Ohms resistor near to that pin and connect the actual external circuitry to that resistor (on the diagram, this is called the AC5-Load).

AC5 and AC5-Load are different things: AC5 is the pin, AC5-Load is the circuitry that should be connected to that pin (apart from the resistor, which is for Synchronous 245 mode).