Robin2

If the motors in the locomotives are modern and only draw a low current then a voltage step-up module (such as an MT3608) and a 1S LiPo might be the best option as it makes charging easier. Just step up the voltage by the smallest amount that is necessary to get the performance you require.

...R

3 hours ago, AndyID said:

(Up until now I've been using an AVRisp to program the ATtiny44A)

 

If it can be programmed with the AVRisp then it should be programmable with an Uno acting as the ISP. I program the Attiny84, 45 and 1634 with the Uno as ISP. The Arduino IDE includes a program called ArduinoISP.

...R

9 hours ago, melmerby said:

I'm not sure how you would heat sink those devices if you did want to control 43A

Perhaps there is no need for a heat sink?

...R

13 hours ago, Theakerr said:

 and whilst i am not sure I think it would be difficult to drive two servo motors doing different things at the same time. 

An Arduino Uno can control up to 12 servos at the same time and a Mega can control even more without needing any shield or motor driver.

...R

12 hours ago, Theakerr said:

As I understand it the Pololu DRV8825. is specifically for a stepper motor.  The L298 on the other hand will drive a servo or, my special interest, a small DC motor.  So is their a better unit than the dated L298?

Thanks

The Pololu website has a wide range of DC motor drivers as well as stepper drivers. Equivalent products are also available elsewhere.

...R

14 hours ago, Theakerr said:

For us un-initiated name one or two.  Thks

See this recent Reply

...R

On 12/08/2020 at 09:17, Sturminster_Newton said:

Various laser cutting companies may be able to slice up some mdf

Isn't that a 5 minute job with a jigsaw?

...R

8 hours ago, melmerby said:

Texas Instruments? The designer/maker.

AFAIK every big company has marketing guys.

...R

17 hours ago, melmerby said:

Not strickly true as L298 is sold as a stepper motor controller and does have the ability to limit the current.

 

Alas, the marketing guys got their hands on the typewriter

...R

1 hour ago, Warwick said:

I bought a Nema 17 stepper motor and a Dual H Bridge L298N Stepper Motor Driver Controller.

 

An L298N is a very poor choice for a stepper motor driver. You should get a specialised stepper motor driver such as a Pololu DRV8825. A specialised driver has the ability to limit the current to protect the motor and it also takes a lot of the computational load off the Arduino.

HOWEVER you need to choose a driver that can comfortably supply the current required by your motor and I don't know what that is - it will be stated in the motor specifications. The DRV8825 is OK for motors that need 1.7 amps or less.

...R

Stepper Motor Basics
Simple Stepper Code

also look up the AccelStepper library
 

12 hours ago, Fen End Pit said:

One of my main motivations for being interested in this technology is to get away from track power. I want to model dodgy narrow gauge systems where the rail head is definitely not a shiny metal surface suitable for conducting electricity and possibly where the rails are knee high in grass!

 

I have found that some matt paint on the rail greatly improves adhesion on inclines

I have built my own BPRC equipment using the Arduino programming system for 009 models using the Kato tram chassis - that makes it very flexible but only for people who are prepared to do their own construction and programming.  I have no interest in on-board sound but I might eventually experiment with speakers under the baseboards.

...R

2 hours ago, Fen End Pit said:

Are there ways for several operators to swap control of a locomotive in the way you would with DCC?

 

What about something simple like handing the RC controller to the other person?

...R

Generally the sensor will need to be connected to a micro-controller and a wireless device to send messages and the main Arduino will need a compatible wireless receiver.

Probably the simplest MCU/wireless combination is the ESP8266 which can transmit as WiFi or using its own ESP-NOW system. The receiving Arduino will also need to be connected to an ESP8266. ESP-NOW demo

If you want to use a regular Arduino (such as nano) with the sensor then you could use nRF24L01+ modules for the wireless communication. Simple nRF24L01+ Tutorial

...R

6 hours ago, melmerby said:

 

You obviously don't have the patience to look through the components either.

I already have the components I want - LDRs. I don't have the patience to construct an equivalent from parts. I had the impression from your earlier Post that you had found a supplier of a ready-made IR detector that is smaller than an LDR. Apologies if I misunderstood.

...R

2 hours ago, melmerby said:

Those IMHO are the same as the Megapoints ones

 Which are a little cheaper on Aliexpress but take longer to arrive:

 

I don't have the patience to wait for stuff from China. And those devices are several times larger than an LDR

...R

11 hours ago, melmerby said:

Buy your own IR detectors directly, then they will be cheaper and smaller than LDRs

Have you a link to a supplier?

...R

10 hours ago, 47137 said:

I have a Megapoints servo controller board and an Arduino starter kit. Communications between the two will be a serial interface, and the message protocol is simple - 12 bits sent in two bytes to set up to twelve servos.

If you do decide to use your Arduino to control the Megapoints board you need to use I2C to communicate with it. The Megapoints website has some example Arduino code.

However I agree with others that you can control servos directly with an Arduino.

I use Light Dependent Resistors set between the sleepers to detect trains. Megapoints seem to have good value in IR detectors - but they are more expensive and bigger than LDRs.

...R

1 hour ago, 34theletterbetweenB&D said:

Certainly doesn't in OO. You have to go around the track before running to clean off what nature randomly deposits, and I can promise you that the likes of bird droppings, snail goo and the like do nothing for adhesion whatsoever.

I stand corrected and I can see that a big lump of bird sh*t or twig could cause a derailment. But the cleaning would surely not need to be as meticulous with battery power as with track power?

...R

14 minutes ago, TorrinFu said:

I was (off-topic!) contemplating modding an old loco to r/c for a garden railway that never got built, using some micro gear. Put 16v ac onto the track, and a rectifier, receiver and speed controller into the loco. It hasn't got past the thinking about it stage yet.

A garden railway seems the ideal candidate for battery power as it removes the need for track cleaning. Indeed dirty track will aid adhesion.

...R

This is an interesting example of the electrical complexity of introducing an Arduino to a traditional track control system. If the Arduino had been in at the planning stage the turnouts would be operated with servos and the signal LEDs would use 5v  directly from the Arduino.

...R

1 hour ago, PenrithBeacon said:

Deleted, triplicated post! Correction quadruple post, don't understand why.

This happened to me a few days ago and someone kindly pointed there is an option to HIDE a post. 

...R

9 hours ago, Corbs said:

I've been standardising on 1S batteries so far, but the battery life was so shortened by using voltage step-ups

Out of curiosity, what was the voltage stepped up to?

...R

Usually with multiple LiPos the connections to each cell are brought out at the charging point - so a 2S LiPo will have three wires at the charging socket. In effect this allows each cell to be charged separately - which is what balance charging is.

Compared to  model airplanes or racing boats or cars model trains are very gentle on batteries and balance-charging may not be necessary every time. However if you have a proper charger for a 2S LiPo it is probably simplest to use it all the time.

I have 1S LiPos and a voltage booster (boosting to 5.5v) for Kato n-gauge tram chassis in 009 locos. I remove the batteries for charging and I made a simple charger using an MCP73831 charge control chip. Because I have very small cells (240mAh) I was afraid that off-the-shelf chargers would provide a too-high charge current.

...R

10 hours ago, Nearholmer said:

That is very interesting ......... did you then create the DCC signal on-board the loco, and feed that into the decoder, or did you "behead" the decoder and feed it data in a simpler way?

 

I have not used DCC at all but it would certainly be possible to create a DCC signal with an Arduino-type microprocessor

Quote

Is the nRF24L01

using a simple form of radio, or is it a form that is very robust like DSSS or FHSS?

 

I ask, because a simple system is likely to be quite interference-prone.

They are very robust and have a lot of error correction built in. AFAIK the same wireless devices are used within some of the off-the-shelf RC equipment.

...R

41 minutes ago, Regularity said:

Unless operating a very simple layout, then having direct handset-loco connections is a complication. I can foresee the need for up to 4 drivers, with maybe a dozen locos to choose from between them. The centralisation of DCC allows me to do this with controllers, each able to select a loco providing it is not in use.

 

I'm not sure I understand that. Do you mean that you want 4 handsets and each one can select any one of maybe 12 locos?

I made something like that using an Arduino-based system with nRF24L01+ wireless transceivers - they don't "bind" in the way that the Deltang system does so each wireless transmission could be to a different loco and there could be 10 or 20 transmissions per second. With my system the control was from a web browser on my PC or phone (or both) and an user could select any loco that was not already in use by another user. Have a look at this Simple nRF24L01+ Tutorial if you are interested.

...R