Here are some pictures of my computer/manual switch throw. I was looking for a device that I could use to throw a switch both with a manual lever and also have a servo drive it for computer control. This is what I came up with. After a bit of testing, it seems like it will do just what I want. It uses a cheap waterproof servo, three magnets and a styrene throw. There are two magnets on the servo wheel and one on the throw. There is no connection between the servo wheel and the actuator other than the magnetic ‘clutch’. The ‘spring’ wire is a paper clip bent to fit. With the servo off or centered, you can throw the switch manually and it ‘clicks’ to one of the two magnets on the wheel. Under computer control, the servo can rotate to ‘pick up’ the magnet on the arm to throw the switch. Works quite well on the bench so I’ll be installing it soon to test out in Gilbert.
Man, my o-flute-upcut carbide bit does some clean work on .125 inch styrene! This is the design from a few posts down, cut out with the CNC. A waterproof R/C servo provides the automation. The arm has one super magnet, the wheel on the servo has two. The idea here is that you can throw the lever manually to control a turnout but that it also remains at all times under control of the computer.
That’s the plan anyhow. The magnets are those little really powerful ones. They act like a ‘clutch’ in this situation. So far it works on the bench but the real world is another story, I’m not quite there yet. I need to install them on my three turnouts and stick them out in the cold rain for some testing.
My (revised) idea for a switch machine. I want to be able to manually throw the switch or have the servo (computer) take over and set it. One wheel is bound to the servo, the other connects to the turnout throw. Magnets provide the ‘clutch’ effect. You can move the lever by hand to throw the switch or rotate the servo to ‘catch’ the magnet on the free servo wheel. I have a 2D design roughed out as well. I’ll attempt to cut that out with my 3D router but I need to get some 1/32 inch bits first.
Finally got my control system tested out in the woods. Very happy with the range. The Xbee will do 300ft and I can’t even see the RS3 if I go that far away. This is my controlwidgets.com design. All the wireless communications are handled by the Xbee. I can send any sort of data to or from anything with this system in real time. Those are 16 byte data packets that are controlling the throttle and coupler servos.
The RS3 has the throttle, front and rear couplers and single channel sound all hooked up and working. All of it is powered by a 5000mah hour LiPoly battery driving a Pololu 18v7 motor controller. The control widget drives the servos directly. There is also an RFID reader under the fuel tank which works quite well too.
3D Printed Foreman looks over the latest oven fresh widget, complete with 1634R-SU and the Xbee Series 1 with wire antenna. Programmed and tested. The figure is 2.4 inches tall for perspective.
I realized I didn’t have this posted up- this is the single channel mp3 sound card from mdfly.com combined with a simple audio amp. The amp is quite loud and can be built with parts from Radio Shack. This is what I’m using on my RS3 in the pictures below. I’m using the Attiny 1634 s/w UART to drive this from the client widget. It works quite well, you just send a single byte to the card to set the volume or play one of the sounds. However, you get what you pay for, $10 only gets you one sound at a time.
Here are a couple of shots of my control system going into my Aristocraft RS3. The power is all in the back end, I have a 5000mah 14.8v lipo pack driving this beast with a Pololu 18v7 motor controller powering the trucks. A very potent drive train. Anyhow, these pics show the brains- the Atmel 1634 board, the Xbee Series 1 and the MDFly mp3 sound card. Not seen is the RFID reader on the fuel tank- I’ll post that up later. Phew, some work and lots of engineering spits and fails but it’s now pretty clean and works well. I did downsize the controls a bit, I’m only driving the motor, the two coupler servos and the sound card. I left the lights on a manual switch and there is a current sensor in there but I’m not looking at it right now. As mentioned, the RFID is also connected and works so I do have the basics of a computer controlled system. The main control boards are also reasonably accessable by taking off just the short hood of the locomotive so tweaking the firmware, sounds and the pololu motor controller won’t require the entire locomotive to be taken apart (which is a BITCH to say the least!)
Finally have all of the connections wired and (more or less) tested. I’ve added LEDs to the running lights and servos (not shown) to control the couplers. Just need to add about 11oz or so to the fuel tank and put it all back together for final testing. I’ve attached a programming cable to the microcontroller board so I can download new builds or tweak the s/w if required. Phew. This has been quite a bit of development. The control widget itself went through many interations (see controlwidgets.com) as did the power board. I’ve settled on the Pololu 18v7 programmed to only give forward motion with a relay switching between forward and backward. Anyhow, soon we will be doing some real world testing.
Here is my latest stand-alone hand-held-throttle design. It’s based on my control widget thing and I (finally) have it all working.
All the circuits and keyboard are mounted on a 3D printed faceplate with a 3D printed back enclosure. It still needs some structural work, screws to hold the face plate on and I need to mount the power switch too, not sure where that should go.
There is some hard-coded stuff in the handheld software but it does work quite well. I also have a slight design gotcha on my USB interface into this thing but I’ll get that solved soon.