picciux wrote: ATM 4 GPIO left unused. If GPS reset is not used and 3Dfix led can be sacrificed, we could have 6 gpios to let the unit control focuser stepper motors using already available Radeck Astroberry Focuser indi driver. On the power shield side, only a JST like connector to link one of those mini stepper controller modules is needed.
Yes, I am thinking about how to implement it, I do not really want to have the housing bigger, and currently, the front and back plates are full of connectors, based on my testing during the last week, it seems that I have to remove the onboard BME280, because the RPi temperature is influencing it quite much, so if I do so I would have space for another connector.
Do you think a JST 2,54mm pitch connector would be okay for that? I think an RJ11/12 is more common, or?
MCP3202 can be replaced with 3208 and populating 1 INA328 and OP-AMP per channel we'll have amps readings per-device instead of total. Maybe it's an overkill, don't know.
When I have started that design I have also thought about single-channel current measurement, and I am open to modifying it, with a smart MOSFET so I can also remove the fuses because the smart MOSFETs are overcurrent protected. This could help the place a stepper driver on the board.
the OneWire pin can be used to chain one or two DS18B20 temperature sensors to monitor stuff that has to be kept dew-free: since ambient temperature and relative humidity are already available, we can calculate dew point temperature and automatically regulate heaters at minimum power needed to keep dew away. Obviously lacking (or not working) the sensor, the channel works in manual power mode. I've already done it with Arduino, code is simple and I can contribute it.[/quote]
As I mentioned previously the onboard BME280 cannot be isolated 100% from the RPi, so I am planning to remove it, and maybe add two 3,5mm jack connectors, one for I2C sensors, like BME280, and one for one-wire sensors. Let's see how all these fits on the board.