Note to Self - Remember the resistor!

In between other duties I managed to put together the circuit described in the MERG journal but it didn't quite work correctly. As I did it on a breadboard instead of the stripboard as I wanted a temporary setup, possibly there was an incorrect wiring. Any way while I was mucking around with this I thought about checking the semaphore lamp after I had painted it black (as per quite a few prototype photos I found on the Net) to reduce the 'through plastic' brightness. I quickly wired up the 9V battery and the lamp glowed pretty brightly. A bit TOO brightly before dimming rapidly. What just happened I thought? Then it dawned on me, the RESISTOR! I forgot the resistor hence the extreme lighting. Damn! However it didn't completely stuff up the LED and there was a dim glow once I put a low resistor (68ohms) on the +ve wire. Not to worry as this was the experimental kit. I can always position the semaphore so that the lamp isn't seen.

Today I decided to connect the servo up to the MERG CBUS servo controller to see if it would work. Yep it did. With a bit of fine tuning with the help of the control software I think it works very well. I also connected up the lamp (with a resistor this time!) to video the movement with illumination. Below is the video.

This week not sure what I will do. Maybe get back to the Raspberry Pi as it has been nearly 3 months since I last mucked around with it (just before Christmas last year in fact!)

Semaphore done..Now to automate

This week I was only able to finalise the semaphore. This entailed mostly painting in the wires. Today I bodgied up a jig from some ply offcuts for putting the semaphore in as well as holding the servo to automate the arm.

Below are the photos promised in the last post as well as what has been done this week.

This week I will probably only be doing the automation. Instead of the MERG module to automate, I might bung up on the breadboard a servo controller articulated in the latest MERG newsletter to see how it goes. If it doesn't the MERG module will be Plan B!



LED wires superglued along the post



Wires leaving the post and into the base hole



View of the wires in the base hole.
I could have used a smaller diameter drill in hindsight.



Close up view of the 'orange' LED from the front



View from the front. Note the red ball at top



View from the rear, wires just visible

View from read side.
Sorry the original is portrait but no idea why this
isn't!

 

Semaphore in temporary jig

Straight on view of servo in jig

Elevated view of servo in jig

 

 

 

 

 

 

 

Semaphore kitbashing begun

This week in between other commitments I made a start on adding a working lamp to the Ratio semaphore. In hindsight and on future conversions I will do the following actions BEFORE assembling it! Retrofitting is a tad problematic.

I started by drilling out the lamp 'lens' straight through to the back end. Then taking the knife I started opening up the round drill hole into a rectangle to accept the SMD LED I had purchased from LedBaron. I was working with the magnifying glasses headband but after a while of being EXTREMELY careful with the razor sharp knife I was getting crosseyed trying to see what I was doing. There had to be another way? The next day I thought of using a rotary burr in my rotary tool. That night I checked what I had but the smallest burr I had was too big. I needed something 1mm or smaller in diameter to fit into the drilled out hole with sufficient room to carve out more material. The following day a bit of research on the Dremel page (my rotary tool isn't a Dremel but I was hoping for maybe a 'standard' amongst these tools?) and I found too bits that fitted the bill. Both were 0.8mm in diameter. One was a round burr and the other a straight sided cutter. The latter one was sounding really promising. I picked these up from Bunnings that night after one of my commitments. By the time I got home it was too late to do any modelling. The following night I was going to give it a whirl. When I got to it and went to insert the straight sided bit into the collet, the shaft was smaller than what the collet would accept. I rummaged amongst the bits tray but nothing smaller. I needed a 3/32" collet. Back to the Dremel site and they had such a beasty. I was able to pick up said collet from a hardware in the city on Friday. A quick check Friday night and the collet fitted the shaft and the bit went in perfectly. I'd had a few reds Friday evening so wasn't going to tempt fate on something so small, so I would have to wait until Saturday night. 

Saturday night came and so did a reasonably sober Greg ;-) With magnifying headband on, and the tool spinning away like a mad thing, it was time to make a start. Ever so carefully I sliced away plastic a fraction at a time and tried the LED fit bit by bit. I finally got to a point where the LED fitted into the space. A dabs of superglue and the LED was installed. I forgot to mention that earlier in the week I had applied some Tamiya Clear Orange onto the LED lens to imitate a incandescent lamp.

Tonight I temporarily wired up a 9V battery and resistor to the lamp and it worked. A bit too bright in my opinion so will need to tinker around with the resistor to really crank the brightness down to something more prototypical. I'm pretty sure that semaphore lamps were fairly dull in brightness rather than spotlight bright!

I had taken some photos to put up but just found that they were out of focus ever so slightly. I will retake this with another camera through the week and upload. Maybe I will complete the kitbash by gluing down the wires along the post, paint white and black where required, and glue the other fixtures (ladder, hoop, etc) to the post. Then it should be ready to connect to a servo and test this feature.

So that might be what the upcoming week will be about. Still no progress with the Pi and JMRI. Having too much fun with the modelling at the moment, which is the purpose of the hobby is it not?

Not much this week

This week has been busy getting over the events of last weekend, otherwise known as The Big Blow ;-)

I did purchase some tins of Humbrol paint, epoxy filler (just in case of poor fitting), and some paint brushes ready for when I glue up the Dapol kits purchased awhile back.

I posted an earlier update to my written articles page, and that was about it.

Hopefully a better week this week re modelling or getting back to the Pi.

'Articles that I have written' page updated

I have been a bit tardy re this page and only just realised that I hadn't updated with respect to the article I wrote for Continental Modeller back in 2011 on installing a Loksound Select into a Trainorama NSWGR 44 Class!

I have updated it with a copy of the article, which looks so much better than my submitted notes to the magazine!