ge_rik wrote: ↑Mon Nov 14, 2022 12:26 pm
I'd love to see/hear more about the system overall. Do you use a compressor or manually pump up a pressure vessel (eg an old inner tube) at the start of a session? What do the operating switches look like? Etc.
Rik
I'm using a small compressor from a air brush set as its pretty quiet, i was previously using a 24Ltr one such as this
https://www.screwfix.com/p/stanley-b6cc ... 230v/48089 but when it kicked it all of a sudden it gave you quite a shock!
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The Controls i use are 12-24V solenoid valves as its all computer controlled, the same reason i use a compressor instead of having to manually pump pressure up.
The solenoids sit in a 4 way manifold to attach the tubing to and are simply open when power on and closed when power off. I run 16 of them directly from a 16 way accessory controller and have no issues with power or overloading the controller (Digikeijs DR4018). The pink plastic bit is just a 3D printed holder for them to sit in, holder screwed down to shelving.
The alternative is manual control using some switches the same size as the minature toggle switches used on many OO gauge control panels.
https://www.sunsetvalleyrailroad.com/pneumatics.html
I have a couple of these manual switches, one is open to the world to vent the whole system down at end of a session or when needed and the other controls a trailing line on the workbench for testing / prototyping etc without having to have the PC control side powered up a running.
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Air distribution from the compressor is via simple manifold.
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I also have a standard point actuator / point motor fasted inside the control box operating a micro switch which the computer can sense, this is a safety system so if air pressure drops it stops everything on the DCC and wireless DCC. (Wired fail safe so the switch has to be held "on")
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The actuators themselves are fitted with an internal spring return so they push out when they get air pressure then when the solenoids release (and vent the air from that line out through their open top into the world) the spring shifts the points back.
Even on a relatively low pressure they are a force to be reckoned with, easily crushes twigs in point blades and pushed stones or ballast out of the way.
A problem i have wanted to solve for quite a while is active feedback from each set of points, I'm currently planning on making a device which fits opposite side of the point to the actuator and uses an electronic switch (probably a sealed reed switch with a magnet) to confirm the blades have actually moved.