Focalplane
Western Thunderer
Simon
I remove the Peco over centre spring but still need stronger piano wire.
Paul
I remove the Peco over centre spring but still need stronger piano wire.
Paul
7mm Birmingham Moor Street
- Thread starter Focalplane
- Start date
simond
Western Thunderer
Morning!
Interesting. Maybe the wire is less stiff than the stuff I had - or maybe I changed mine when I first used the Tortoises on the previous layout, The Greater Windowledge Railway.
Off to work, will hopefully box off the last issue with the sketch tonight, but either way, I’ll post something that at least works so you can make your steppers go, check out the limit switches etc. I’ll then sort out the finer details afterwards.
Best
Simon
Interesting. Maybe the wire is less stiff than the stuff I had - or maybe I changed mine when I first used the Tortoises on the previous layout, The Greater Windowledge Railway.
Off to work, will hopefully box off the last issue with the sketch tonight, but either way, I’ll post something that at least works so you can make your steppers go, check out the limit switches etc. I’ll then sort out the finer details afterwards.
Best
Simon
Ressaldar
Western Thunderer
Hi Simon,
why leave the Peco spring in, the Tortoise is more than capable of holding the tie bar in position and I agree with Paul that the supplied piano wire is not man enough for O Gauge tie bars - as hinted at in the Tortoise instructions, I use 0.9mm piano wire.
Having said that, I have a major problem with one Tortoise at present in that whilst the motor mechanism sounds as if it is working, the drive mechanism that the piano wire fits into is totally seized up and needless to say, it is in the most awkward position on the layout to work on
- the only good access is to tilt the layout onto its side and there is too much loose gravel etc to preclude that! I have been able to remove the piano wire and replace the Peco spring and will install a mono frog juicer to switch the polarity of the frog - I can just about reach the wires to the frog and track power - watch this space.regards
Mike
ps our next Open Day is 9th June if you are up visiting.
Ressaldar
Western Thunderer
Hi Simon,
remaining dates this year - 11th August (I'll miss that as it is SWMBO's birthday) 13th October & 15th December
Apologies to Paul for hi-jacking his thread.
regards
Mike
simond
Western Thunderer
Mike,
Thanks, I’ll see if I can tie in.
Paul,
Herewith another turbo-tedious video
It now accelerates, runs at constant speed, and then decelerates again.
Need to combine this with the actual travel and the desired speed, a job for tomorrow.
It’s actually more of a fiddle than I expected getting the accel and decel to work smoothly. Still, I’m learning!
Atb
Simon
Thanks, I’ll see if I can tie in.
Paul,
Herewith another turbo-tedious video
It now accelerates, runs at constant speed, and then decelerates again.
Need to combine this with the actual travel and the desired speed, a job for tomorrow.
It’s actually more of a fiddle than I expected getting the accel and decel to work smoothly. Still, I’m learning!
Atb
Simon
simond
Western Thunderer
If you look & listen carefully, there is a small but noticeable change in speed at the end of the first and third rotations.
This is where the loop that calculates the acceleration hands over to the loop at constant speed, and then to the loop that decelerates it again.
There is one line (very simple, integer sum) of code which different in the three phases, it’s minus in the first, missing in the constant speed phase and plus in the third, and this is enough to cause a subtle change in speed. I’m quite surprised that it’s evident at all.
This evening, I hope to pull all the bits together and get a smooth acceleration from “barely moving” to “10 (scale) feet per minute” and back to barely moving in the 17 rotations that will give 85mm travel.
Don’t hold your breath...
Best
Simon
This is where the loop that calculates the acceleration hands over to the loop at constant speed, and then to the loop that decelerates it again.
There is one line (very simple, integer sum) of code which different in the three phases, it’s minus in the first, missing in the constant speed phase and plus in the third, and this is enough to cause a subtle change in speed. I’m quite surprised that it’s evident at all.
This evening, I hope to pull all the bits together and get a smooth acceleration from “barely moving” to “10 (scale) feet per minute” and back to barely moving in the 17 rotations that will give 85mm travel.
Don’t hold your breath...
Best
Simon
Focalplane
Western Thunderer
I am holding my breath with excitement! The mechanical side is slowly coming together, I bought the necessary metric bolts yesterday afternoon. The Tufnol may arrive tomorrow.
Merci beaucoup! Paul
Merci beaucoup! Paul
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Chris Klein
Active Member
This reminds me of an apocryphal story of a very elderly lady who sailed on the Titanic as an infant. She was asked by a journalist what the secret to her long life was; her answer, "Getting off the Titanic."
Jordan
Mid-Western Thunderer
Yes Moor St was/is compact. It was postulated as a 'Basis for a Layout' by Chris Ellis in the old Airfix Model Trains magazine, way back about 1980/81, coinciding as I recall with the release of Lima's 4mm DMUs.
simond
Western Thunderer
Ok, it works 
Approximately 17 turns and just over 50 seconds each way. There’s some leeway to adjust the speed, faster is easy enough, but getting it to go slower, smoothly, has been a bit tedious.
It’s scruffy so I’m going to tidy it up, and will have to post from the other computer. I’ll comment it so it’s intelligible. But not tonight!
Atb
Simon
Approximately 17 turns and just over 50 seconds each way. There’s some leeway to adjust the speed, faster is easy enough, but getting it to go slower, smoothly, has been a bit tedious.
It’s scruffy so I’m going to tidy it up, and will have to post from the other computer. I’ll comment it so it’s intelligible. But not tonight!
Atb
Simon
Focalplane
Western Thunderer
Simon
That looks fit for purpose! Thank you. The Tufnol wasn't delivered today and has been rescheduled for Friday afternoon. I may be able to start assembling the electronics by then (we are out all day tomorrow) and can then set up a test rig to run the sketch using the linear motor. By then I am sure I will have a load more questions!
I do have a piece of Tufnol suitable for the wagon hoist platform but no linear motor to raise and lower the hoist - it will need a longer travel than 10 cms if it is to work properly with a subterranean track holding several vans to be shuffled by hand.
It has occurred to me that additional arduinos might used to drive the capstan winches which were used instead of horses to move the wagons within the hoist roads. Well, that might be more trouble than it's worth!
Cheers, Paul
That looks fit for purpose! Thank you. The Tufnol wasn't delivered today and has been rescheduled for Friday afternoon. I may be able to start assembling the electronics by then (we are out all day tomorrow) and can then set up a test rig to run the sketch using the linear motor. By then I am sure I will have a load more questions!
I do have a piece of Tufnol suitable for the wagon hoist platform but no linear motor to raise and lower the hoist - it will need a longer travel than 10 cms if it is to work properly with a subterranean track holding several vans to be shuffled by hand.
It has occurred to me that additional arduinos might used to drive the capstan winches which were used instead of horses to move the wagons within the hoist roads. Well, that might be more trouble than it's worth!
Cheers, Paul
Focalplane
Western Thunderer
OK, this morning I shall start on the Arduino electronics. Don't expect miracles but I will try to cover everything I do, step by step.
Simond has been a great help, actually that's an understatement, I would not have known where to start or what to do.
The first step was to calibrate the Droking 5 volt regulator, using a 12v DC 1 amp power supply unit I had in my spares box, originally for street lighting, etc. The 5 volt regulator has + and - inputs and + and - outputs and a little blue box with a flathead screw which is used to adjust the output voltage down to 5 volts. I found this out from reading comments on line as there is no apparent instruction sheet available with the regulator.
I attached the power supply to the inputs and stuck the multimeter probes into the correct outputs and adjusted the screw until it read just under 5 volts. I detached everything, wired up again and checked that the voltage stayed the same. It did.
I am hoping this power supply will be sufficient for all three Arduinos but if not, I will simply buy a heavier one.
Next will be to start assembling the printed circuit board, following a diagram from simond.
Simond has been a great help, actually that's an understatement, I would not have known where to start or what to do.
The first step was to calibrate the Droking 5 volt regulator, using a 12v DC 1 amp power supply unit I had in my spares box, originally for street lighting, etc. The 5 volt regulator has + and - inputs and + and - outputs and a little blue box with a flathead screw which is used to adjust the output voltage down to 5 volts. I found this out from reading comments on line as there is no apparent instruction sheet available with the regulator.
I attached the power supply to the inputs and stuck the multimeter probes into the correct outputs and adjusted the screw until it read just under 5 volts. I detached everything, wired up again and checked that the voltage stayed the same. It did.
I am hoping this power supply will be sufficient for all three Arduinos but if not, I will simply buy a heavier one.
Next will be to start assembling the printed circuit board, following a diagram from simond.
Focalplane
Western Thunderer
Next, soldering the terminal strips to veroboard for the Arduino Nano and the Stepper Controller. I haven't soldered veroboard for many years and found it surprisingly difficult. So I won't show you the soldered side. But I did check all connections for either continuity or shorting out as appropriate:
Various connections need to be made with outside items, e.g. motor, switches, power supply and so on, so two additional connection strips were added along the edges of the boards ready for jumper leads:
Next I added the two PCBs and connectors to various switches, etc. but now I have come to a stop until I hear from Simond!
Various connections need to be made with outside items, e.g. motor, switches, power supply and so on, so two additional connection strips were added along the edges of the boards ready for jumper leads:
Next I added the two PCBs and connectors to various switches, etc. but now I have come to a stop until I hear from Simond!
Focalplane
Western Thunderer
I have turned my attention to the Tufnol board which was delivered this afternoon. I cut the boards to the size of the traverser tables and also cut the wagon hoist table at the same time. I then drilled holes in the brass subframe and the Tufnol and bolted them together with countersunk bolts and lock nuts.
This then told me how much deeper the traverser floor needs to be so that the rails are at the same height. I used rail with C&L chairs welded to the Tufnol to lay the centre track and with temporary packing lowered the floor, set up the table and proved to myself that the mechanics will work by rolling the traverser by hand with the Large Priaire on it.
The next job will be to drill four holes in the centre of the Tufnol table to bolt it to the linear rail slide which will be mounted underneath, out of sight. The countersunk bolt heads will be hidden by additional riveted "steel" plating as in the prototype. Then the platform walls can be added.
This then told me how much deeper the traverser floor needs to be so that the rails are at the same height. I used rail with C&L chairs welded to the Tufnol to lay the centre track and with temporary packing lowered the floor, set up the table and proved to myself that the mechanics will work by rolling the traverser by hand with the Large Priaire on it.
The next job will be to drill four holes in the centre of the Tufnol table to bolt it to the linear rail slide which will be mounted underneath, out of sight. The countersunk bolt heads will be hidden by additional riveted "steel" plating as in the prototype. Then the platform walls can be added.
Focalplane
Western Thunderer
This evening I added the two other traverser tracks (which locomotives never used) and set up a complete traverser operation (by hand):
Train arrives, locomotive uncouples and moves onto centre road of traverser:
Locomotive on traverser:
Traversing:
Locomotive arrives at Release Road:
Locomotive moves off traverser and travels down the release road.
And back down to take the train out again:
Train arrives, locomotive uncouples and moves onto centre road of traverser:
Locomotive on traverser:
Traversing:
Locomotive arrives at Release Road:
Locomotive moves off traverser and travels down the release road.
And back down to take the train out again:
simond
Western Thunderer
Paul
It’s late, as I explained.... but don’t connect your traverser table rigidly to the carriage on your leadscrew thingy. The rigidity of one will fight that of the other. A simple link will suffice.
Or one pin, not 4 bolts !!!
This will likely be different for the lifts.
Atb
Simon
It’s late, as I explained.... but don’t connect your traverser table rigidly to the carriage on your leadscrew thingy. The rigidity of one will fight that of the other. A simple link will suffice.
Or one pin, not 4 bolts !!!
This will likely be different for the lifts.
Atb
Simon
Focalplane
Western Thunderer
Hi Simon
Yes, I agree about the rigidity but I also need to keep the traverser "straight" so perhaps two links would be a good idea?
Paul
simond
Western Thunderer
Hi Paul,
Does the traverser try to go “off square” now, without the carriage connected to it?
I’d expect that with the wheels you’ve fitted, it stays aligned?
If not, I think it would be better to sort the alignment at this point, effectively above the baseboard, and have a pin in a slot to connect to the carriage.
You don’t want it to be “hyperstatic”, nor indeed, insufficiently constrained.
A bientot
Simon
Does the traverser try to go “off square” now, without the carriage connected to it?
I’d expect that with the wheels you’ve fitted, it stays aligned?
If not, I think it would be better to sort the alignment at this point, effectively above the baseboard, and have a pin in a slot to connect to the carriage.
You don’t want it to be “hyperstatic”, nor indeed, insufficiently constrained.
A bientot
Simon