OpenSprinkler Forums Hardware Questions OpenSprinkler Pi (OSPi) OpenSprinkler PI stopped working… Reply To: OpenSprinkler PI stopped working…



I was looking at the specifications for the OpenSprinkler pi (reproduced here):
Input​ ​Voltage:22V​ ​AC​ ​to​ ​30V​ ​AC.
DC​ ​Output​ ​Current:500mA​ ​@​ ​5V​ ​(to​ ​power​ ​RPi).
Number​ ​of​ ​Zones:8​ ​on​ ​the​ ​OSPi,​ ​expandable​ ​by​ ​linking​ ​zone​ ​expansion​ ​boards.
AC​ ​Output​ ​Current:800mA​ ​continues​ ​@​ ​24V​ ​AC​ ​per​ ​zone​ ​/​ ​station,​ ​8A​ ​impulse​ ​/​ ​inrush.
Over-voltage​ ​Protection:48V​ ​bi-directional​ ​TVS​ ​on​ ​each​ ​zone,​ ​AC​ ​input,​ ​and​ ​rain​ ​sensor​ ​terminal.
Over-current​ ​Protection:2A​ ​on​ ​AC​ ​input;​ ​1A​ ​on​ ​5V​ ​DC.
Size:135mm​ ​x​ ​100mm​ ​x​ ​32mm​ ​(5.3”​ ​x​ ​4”​ ​x​ ​1.26”)
Weight:150g​ ​(5.3oz)​ ​w/o​ ​RPi

I don’t see where the over-current protection comes from.
For the AC, I see one connector directly connected to GND, the other connected directly to the COM connector. The triac connects the pin of the solenoid directly to GND. I see no circuitry to limit the current.
For the 5V, I see a switching power supply configured for 2A with a 12V input This part has a current limit, but it is significantly higher than 3A. I don’t see any other current limiters on the 5V.
I do see the TVS diodes for voltage limiting, I just don’t see any circuitry for current limiting.
Can you tell me how you came up with the over current protection numbers?