Odd experience with SBrick and PFx brick

[zephyr1934]

Let me start out by saying that ultimately there was nothing wrong with either the SBrick or the PFx brick...

So I went to Brick World this summer with a full car, but I brought along an extra box with my Superliners in it by request to show it to someone. I finally get a moment free and bring it over to the CincyLUG layout to enjoy some of the largest radius curves to be founds. Long ago I had problems with the IR receiver dropping out due to too much current demand, so I got my first SBrick and it worked like a charm. It also gave me the power off Bluetooth control, with no need for line of sight. Well, that !@#$% train would not make a full loop without dropping the BT connection and coming to a stop each time. Earlier in the show several of the heavy duty train builders were complaining that BT had become useless at shows given all of the competition in the bandwidth. So here I am figuring that demand is pushing me out of BT control. Meanwhile, Michael G. of BT fame was talking to Andy M. of BrickTrainDepot et al. fame about the PFx brick and I was wowed. It supported both BT and IR connections, what's more, you can get an extension cable for the IR receiver so that you can discretely mount it away from the control block. I ordered one that night.

Anticipating the show we had today, I swapped out the SBrick for the PFx brick about a week ago and started to explore the UI. After some futzing around I got it working with both BT and IR. Excellent, and here I now have sound too (with the additional speaker).

Anyway, the show starts today (well, yesterday at this point) and I'm looking forward to getting the upgraded train running... and !@#$%, the BT drops out before it makes a full loop. It wasn't doing this behavior at home. Good thing with the PFx brick is that you can set it to keep going if you lose BT (I've heard that might also be possible with the SBrick, but I don't know how). So the train keeps going even though I've lost the control. I can reacquire the PFx brick, but it keeps dropping out. Fortunately I still had the IR back up control and it worked perfectly.

After I finish up running this train, I pull out my other heavy train, also equipped with an SBrick. Ran for two hours without dropping. So much for the "too much demand for BT theory". So later in the day I try checking connections, swapping the cord from the battery to the PFx brick and even swapping the battery in the locomotive for the Superliners. Nothing works (but by this point I'm getting proficient in disassembling the locomotive).

So that gets me thinking, could it be the one thing left that I did not try to swap out, the motors? I don't have any spares at the show, so it waits until I get home. First, I check to see if I can replicate the BT dropout problem with a little running on my track at home. Indeed, after a couple of laps it dropped out, so I could actually test it. I swapped the motors and "poof" the BT problem seems to have vanished (though I haven't given it the show test yet).

So it would seem to have been one or both of the train motors causing the BT to drop. Is there any basis for a motor making the BT controller drop its connection from not one but two different providers BT based train controller?

[Tcm0]

I think that there might be fluctuations in voltage and current when the motor changes the speed fast (especially with XL motors) which might have effects on the receivers.

[coinoperator]

3 hours ago, zephyr1934 said:

Is there any basis for a motor making the BT controller drop its connection

A bad motor, ie burned windings / shorted collector, may draw too much current wich causes the tension to drop below acceptable value's for the BT.

[raised]

Seems to be a lot like my problems with the BT Modules of these bricks. I only have one PF train motor so I never checked.

Interesting though, I almost never used the PF train motor I have experienced problems with, before installing it in this loco, so I never thought about this thing being the troublemaker to begin with...

However, thinking about it, it could indeed be the case that this is the problem!

But... Did you try these tests with full or half empty batteries? 

Edited August 18, 2019 by raised

[dr_spock]

Maybe RF interference from big electric motors?  Location of motor and the BT antenna.  Try re-orienting the PFx box or move to a different part of the engine or train to test.

 

[Jeffinslaw]

Appreciate you bringing the Superliner to BW! Was fun to see! Definitely some odd behavior with BT. All of our projects at school that called for a BT connection were incredibly frustrating. Try connecting to a generic BT transmitter that ~50 other people in your class have and are also trying to connect to lol.

-Jeffinslaw

[zephyr1934]

So day two of the show and the new motors definitely helped. The PFx brick did still drop 2-3 times, but it would stay connected for at least 30 min. Though as the LiPo battery was nearing exhaustion it would not connect at all. The SBrick on the other train dropped once.

Meanwhile, thanks all for the comments and suggestions...

18 hours ago, coinoperator said:

A bad motor, ie burned windings / shorted collector, may draw too much current wich causes the tension to drop below acceptable value's for the BT.

A much more precise description of what I was thinking. There might still be some life left in those motors for IR control though (there is no other apparent problems with them). These motors are probably my hardest run PF motors so if any of my motors are going to be problems, these should be it.

 

16 hours ago, raised said:

But... Did you try these tests with full or half empty batteries? 

The tests on day one were with full batteries. As noted above, on day 2 the PFx did not connect when the battery was near dead. In the past the SBrick would stay connected until the battery died.

 

14 hours ago, dr_spock said:

Maybe RF interference from big electric motors?  Location of motor and the BT antenna.  Try re-orienting the PFx box or move to a different part of the engine or train to test.

Good suggestion. Throughout both the SBrick and PFx brick were a reasonable distance away from the motors (about as far as you can get while being in the same locomotive) and the SBrick worked fine in its location for several years. Then in the diagnostics the PFx brick moved around a few times. The final location was the same before/after swapping the motors. So I don't think that was a (significant) factor in this case.

 

1 hour ago, Jeffinslaw said:

Appreciate you bringing the Superliner to BW! Was fun to see! Definitely some odd behavior with BT.

Oh a simple pleasure, it is still one of my favorite trains. Knowing what I now know, I wish I had tried my North Coast Limited with the new heritage unit. Instead, it had it's madden run yesterday. Speaking of which... I need to post about that engine...

 

1 hour ago, Jeffinslaw said:

All of our projects at school that called for a BT connection were incredibly frustrating. Try connecting to a generic BT transmitter that ~50 other people in your class have and are also trying to connect to lol.

Yeouch!

[raised]

Just thinking: Did you try putting your BT control device in the same train, ie. in a gondola or something like that, so that it stays in range all the time? Just to test to see what happens if the BT receiver and transmitter do stay in range. 

Edited August 19, 2019 by raised

[coinoperator]

3 hours ago, zephyr1934 said:

motors are going to be problems

If shorted collector you can fix that.
Disassemble the motor, take out the anchor en scratch the dirt out between de collector segments.
Maybe replace the brushes if you can find look-a-likes (or file others to fit)

I've done such repairs on motors in vintage arkade games (pre video) but these were impossible to get hold of while PF motors are still plenty around.

Edited August 19, 2019 by coinoperator

[zephyr1934]

20 hours ago, raised said:

Just thinking: Did you try putting your BT control device in the same train, ie. in a gondola or something like that, so that it stays in range all the time? Just to test to see what happens if the BT receiver and transmitter do stay in range. 

It was clear that swapping out the motors made a big difference. The layout was 30 ft and the tablet was within 20 ft of the furthest point on the loop. BT dropping out once an hour does not strike me as bad for a show that potentially has a lot of BT interference.

 

18 hours ago, coinoperator said:

If shorted collector you can fix that.

Aside from the BT interference there does not appear to be anything wrong with these motors. So they are just downgraded to strict IR duty now.

[Roadmonkeytj]

So this has me thinking ... Obviously BW will have alot of "hubs" ... So there is always going to be the issue at lego shows.  I know our club had no issue running 4 hubs within 10' of each other at the last train show (we were the only lego display though) so im curious to see our local BW as we plan to have more BT on our layout alone not to mention other displays BT.  Out of curiosity were you running off the controller or the API App?

[ALCO]

Just curious, has anyone developed an "sbrick", "pfxbrick" or the like equivalent that uses Wi-Fi 5ghz? Seems like this frequency will have much less interference and greater range at least adequate for shows. Could still be controlled with an app and the signal could be either direct from the controlling device or from an AP for running multiple trains. I don't know enough about the hardware required or if it would be feasible. But just a thought.

[dr_spock]

7 hours ago, ALCO said:

Just curious, has anyone developed an "sbrick", "pfxbrick" or the like equivalent that uses Wi-Fi 5ghz? Seems like this frequency will have much less interference and greater range at least adequate for shows. Could still be controlled with an app and the signal could be either direct from the controlling device or from an AP for running multiple trains. I don't know enough about the hardware required or if it would be feasible. But just a thought.

Technically it can be done.  5GHz components aren't as inexpensive as 2.4GHz components.  5GHz has less range than 2.4GHz. (higher frequency, lesser range).  One of the issue with wireless is congestion when there many devices using the same frequencies present like people with cell phones who leave their wifi and bluetooth turned on.

[zephyr1934]

On 8/21/2019 at 12:42 AM, Roadmonkeytj said:

Out of curiosity were you running off the controller or the API App?

The SBrick only supports the BT app (and other BT that emulates the app), but the train with the SBrick had no problems. The other train, that first had problems with the SBrick, then had problems with the PFx brick, worked just fine with the IR controller support on the PFx brick. Then I swapped out the motors and the PFx brick worked fine for BT. Also, the PFx brick has the option to keep running if BT loses connection (similar to the IR train controller), so even though I lost connection, the PFx kept that train going. I don't know if SBrick supports an option to keep moving on BT loss, if it does I haven't found it.

On a side note, the PFx brick has some amazing sounds, and it is really loud in my basement. But at the show you could hardly hear it. So if you are doing PFx primarily for shows, I would suggest that maybe you try sound on a single locomotive before heavily investing in the sound aspect. Also, if you are going for IR back up, consider the extension cables they sell for the IR receiver.

[supertruper1988]

22 hours ago, ALCO said:

Just curious, has anyone developed an "sbrick", "pfxbrick" or the like equivalent that uses Wi-Fi 5ghz? Seems like this frequency will have much less interference and greater range at least adequate for shows. Could still be controlled with an app and the signal could be either direct from the controlling device or from an AP for running multiple trains. I don't know enough about the hardware required or if it would be feasible. But just a thought.

I know that 4DBrix has a Wifi controller that works with their layout software. 

https://www.4dbrix.com/products/train/2-01-006-train-controller/

 

Looks like it is 2.4GHz Im sure @Lowa could fill us in on the details. 

[ALCO]

16 hours ago, dr_spock said:

Technically it can be done.  5GHz components aren't as inexpensive as 2.4GHz components.  5GHz has less range than 2.4GHz. (higher frequency, lesser range).  One of the issue with wireless is congestion when there many devices using the same frequencies present like people with cell phones who leave their wifi and bluetooth turned on.

Yes, 2.4GHz has greater range and can go through walls better, but in the show environment, how many cinder block walls will one need their Wi-Fi signal to pass through? Also, it's more congested.

5GHz has less congestion and for a show, if using an access point (router) centrally located in the layout, range should not be an issue.

2 hours ago, supertruper1988 said:

I know that 4DBrix has a Wifi controller that works with their layout software. 

https://www.4dbrix.com/products/train/2-01-006-train-controller/

 

Looks like it is 2.4GHz Im sure @Lowa could fill us in on the details. 

Thanks! I will check that out. Not that I need any of this equipment but reading this conversation made me think of Wi-Fi as a possible solution to the Bluetooth connectivity issues in the OP.