Sunday, July 5, 2015

Working on Some Electronics

This week I was spending some time trying to get some electronics working.  A couple of weeks ago I came up with a plan to implement a level crossing flasher across the Bruxner Highway, just on the southern side of Cassino (and I suppose another at Hotham Street on northern side of Cassino and a third on West Street on the Eastern side of Cassino).  The plan involves the level crossing flasher circuit being triggered by track detectors (photoresistors in the track), that can detect either an Up or Down train separately.  The circuit will detect a train in the distance and initiate a flash of the crossing lights, but it will turn off the lights as soon as the last carriage is clear of the crossing.  That way the impatient car driving locals on my layout will be able to resume their travels across the track as soon as the train has gone.  But I need to ensure that the opposite direction circuit does not get triggered by the train as it leaves the level crossing. 
Most commercial circuits are good for dual track, where you can place the circuit detection just where you want it on each track.  But on single track, I am not aware of any commercial products that works like a real level crossing.  Some people have the circuit detect equidistant on either sides of the crossing.  That is not good enough for me. Well I am making one that works prototypically!  I will submit the final description here on my blog along with circuit plans when it is successfully installed on the layout and also send an article off to AMRM for their consideration for publication if they are interested. 
So back to my solution.  Well I thought I had this concept figured out, just how everything was going to work.  Taking this from that circuit, and that from another circuit.  I’ve also enlisted the help of some guru mates to check my logic.  However, I made a small mock-up of one of the circuits components with a relay powered from a 9V battery.  However, it would not work.  I asked my guru mates and they said it should work.  So today I threw the 9V battery away and got out my trusty DC train controller that I test all my DCC decoder installs with, set it to about 12V and hooked that up with my relay circuit.  Success!  The relay now works when I have a capacitor across its terminals.  I get a 3 second delay in this part of the circuit.  I then added a second capacitor and now I get 6 seconds.  It is working as designed.
Now while I was scratching my head about getting this circuit to work during the week, I was searching good old ebay.  I found some circuit boards that do what my cheap and nasty circuit does and does it for a variable length of time and at a cheaper price.  Wouldn’t you know it!  So I ordered two of those.  Anyway, I have the first building block of my circuit working.  I just needed to get my components working.  I will cover the alternatives in my future write up.  It will probably take about 3 weeks for the parts to get here from OS.
On Friday night this week, a few of us hit the highway and travelled to Grover’s place for a snag sizzle and a modelling night.  I did not do much while there, but I did solder up eight (8) track snubbers for my DCC buses.  However, I still need a few more to be made.  I also need to install those snubbers.  I also revisited the lighting circuits for my Auscision 73 class loco.  One wire has come adrift from one of the light boards, and I was trying to work out where it has to go back on.  So I think I have identified where it needs to go, and I will try to reattach next weekend and cram everything back under the shell. 
Yesterday was spent at the Club.  I did plan on working on my troublesome container train but I did not get around to it.  I took it to the Club and just brought it home again.  It is now sitting on the track at Acacia Ridge and will get some more time spent on it next weekend.  My initial plan of adding some more weight in the centre sills of the wagons is not possible as the centre sill is enclosed.
Of Friday night, Geoff mentioned about a new Hobby Shop that has opened up down at Browns Plains, 3/45 Grand Plaza Drive.  Its been there about 3 weeks.  It is called Simon Says and covers Hobbies and Games.  I went down to check it out today.  It looks promising.  It is open 9-5 Monday, Tuesday, Friday and Saturday, 9-9 Thursday and 10-4 on Sunday.  It is closed on Wednesdays.  Over time they will increase their range of items for sale. 
Go Queensland!

No comments:

Post a Comment