Electrics
Entry posted by Richard Mawer
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OK, it may be crude and rather Heath Robinson, but at least I've made it myself and it works. Subtlety and tidiness will come with practice. This is the diode matrix to control the pointwork leading into the hidden storage loops. The con strip for the outgoing pointwork is in place at the bottom.
The route selection buttons are 4 meters away from the CDU and point motors, so to reduce loss to a minimum I have used a heavy duty CDU and mains cable. I now just hope the small push buttons on the panel will be man enough and that if a selection only results in one motor firing, that it won't burn out. It has two chances!
Once these are all in place and working I can move on to the next challenge - operating the two double junctions on the circuit. One leads to the storage loops and other to the incline (more of which another time).
For all points and signals apart from the storage loops, I have decided to use servos. These are inexpensive and can operate in slow motion. You can even add a bounce to the signal arms! I have bought my first batch and also become a member of MERG.
MERG sell all manner of handy electronic kits including one that operates 4 servos. I need 8 servos to operate the 4 points and 4 signal arms in the vicinity of the twin double junctions. The whole area will be operated from just 4 dpdt switches-one for each point and the signals will automatically show the routes. This part of the layout is going to be operated as an extra task for one of the main operators, so simplicity rules.
I duly made up my first kit as seen below. Sorry for photo quality.
It looks complicated, but the instructions are second to none and I found it very easy. It took about 2 hours all in and I was being very careful! You then download the software from the MERG site, connect the board to your laptop via a serial cable and programme which servo you want to move from position 1 to position 2 at what speed etc and the board remembers it. What could be more easy??? Well unfortunately, it would have been far easier if I had read the final instruction and put the correct voltage to the board! I put in 16v ac instead of 9v ac. End result?? - a new capacitor required - but its not the end of the world. We live and learn.
So once these teething problems are overcome - and I've learned to read - I will be able to programme the servos for the points. I have yet to make the bracket signals.
The next challenge will be to mount the servos under the baseboard - I'm thinking of very strong sticky pads (servo tape?) any better ideas that don't cost a fortune (I have about 90 to do!) - and then thin piano wire or guitar string wire to connect the servo arm to the tie bar. The over-centre springs have already been removed from the points. There needs to be a bit of "give" or spring in the wire to apply a small force to the switch blade when against the side rail, but not too much : more trial and error!
At my current rate of progress, that will be January, but I hope not.
Thanks for reading.
Rich
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