build questions and minor feedback.

[eMadman]

I'm about to start working on soldering up the PCB and beginning testing. Before I break out my soldering iron and start shopping for screws, I have a few questions:

• Looking at the PCB, it looks like it's calling for 12v to the power header while the non-pcb BOM is calling for a 24v supply. Is it safe to assume that the PCB design is okay to use either 24 or 12v? I'm knowledgeable enough to know how to make a lot of magic smoke, but looking at the PCB in kicad, it looks like the high voltage is only being delivered to the stepper driver and the recom supply is being used to deliver 5v to the ESP32. In my experience with 3d printer stuff, the TMC and the motor can definitely handle either 12v or 24v with more torque and quieter operation at 24v.
• what size screws do I need for the 2.0 case? Looks like I'll need some pretty long wood screws to get through all of it... For a future iteration, I might modify the 3d model to accept smaller machine screws and use brass heat-set inserts for the threads. If this project works for me, I'll probably be making at least one or two more for some friends and that mod might be worth my time.
• took me a while to figure out how the design is intended to mount to the bike - the arm for the mount cracked down the layer lines for me trying to get a clean fit. I Might have to enlarge the part by ~2% to make it more snap-fit friendly for ABS plastic.
• Same challenge with the stepper motor gear - it meshes beautifully with the larger gear, but doesn't fit the stepper's shaft. Easy fix with the cad you've provided. I'll try using a heat gun to soften the plastic before I go with re-printing
• Have you had any concerns with how the stepper rests in the case? THe lack of screws holding it down worries me since it might introduce some play. I can't come up with a better mounting solution besides putting a hole in the chassis and securing the stepper to the case from the rear. I have some 1/8" thick foam gasket tape that might be a good alternative and give the motor more cushion to sit on. I think It'll squish as much as necessary for this purpose and do a good job at reducing rattle from the motor not being screwed in place.

I'll post more here through the course of my work on this. End goal is to use SS2k with QZ and zwift.

[doudar]

Sorry for the delay - I don’t get notifications for discussions…

Yes, the pcb can accept up to 24v.

I’ll get back to you on the exact screw sizes for 2.0 (I’m traveling) but they are a common drywall screw size. The reason was just to try to simplify the BOM.

If you get the exact motor specified, there is no play in the stepper motor. It fits perfectly tight. Very nice actually.

The original case design has stepper mounting screws but 2.0 is better in this regard.

Let me know if you make/need any hardware changes- I’d absolutely love a hardware push request if you make some improvements.

Have Fun!

[eMadman]

Awesome! I managed to solder a board together last week, but unfortunately, I can't get the motor spinning using Qdomyos-Zwift and the gear selection there. I also only just recieved the RCA cables this morning so I can finally wire up the switches.

Best case, it's me misunderstanding how the QZ integration works. Worst case, I messed up on soldering the tmc or have a bad one (wouldn't be my first defective stepper driver from BTT). Either way, If that's the case, I'll consider this board a write-off and potentially practice my desoldering with it at a later date.

I'm also having a thought to use female dupont headers to make this type of troubleshooting much easier... not a fan of the huge amount of extra space that would need in the chassis though.

I will definitely provide updated fusion 360 files if I make changes. The steppers I bought had a JST-like connector which interferes with the motor mount - I was able to trim the mount with my flush cutter - it's just a few mm of material to shave off. I'll take measurements and make that change for sure.

I managed to get wood screws that fit the chassis as well (8 x 1.75")

[eMadman]

Build complete - wasn't my soldering, just my understanding of how it integrates with QZ or just an issue with QZ on my tablet. Anyways, it pairs well with Zwift, which is great!

First ride yesterday went okay - about 15-20 minutes in, I noticed that Zwift no longer showed the correct cadence. Through the logger view on the browser, the SS2k is pulling the correct cadence. I'll try again tonight using a tablet directly on my spin bike instead of a windows PC. It's possible there's interference between the frame of the bike and the PC

Since I'm intending on using this with my schwinn IC4 almost exclusively, I'm thinking the better approach to the SS2k is to redesign the chassis to mount to my bike in a more sturdy way. The stem tube is a square box tube with the corners along the axis of the bike which would make a perfect thing to align the ss2k off of and reduce some slop in it.

@doudar - my next question: I noticed that the SS2k paired with my IC4 and automatically started capturing watts which is great... the ic4 calibration will be real difficult for me since I live in an urban center. Are you at all familiar with the Qdomyos-Zwift integration and what's entailed there? My hope with this project is to have SS2k pair with QZ and have QZ integrate with Zwift as the power meter since that's what I've used as my baseline for calculating power up to this point.

[doudar]

It should work with QZ if you're using the latest version of each. I know they have a few (SS2K) users over there and so maybe you'll want to talk to them to see if there's anything you need special.

Which version of the SS2K did you build? Version 1 or Version 2?

[eMadman]

Thanks! I reached out on the QZ facebook group to ask questions.

I built version 2. Whole process was pretty straightforward. I've got a couple days off this week so I'm hoping to spend a few hours in fusion 360 and try reprinting it. I'm terrible at parametric modeling so it'll be slow going, but you've given a great set of files to work with as a starting point.

[eMadman]

In progress: IC4 specific mount. Length of the crossbar still needs to be measured and figured out.

Done: Case mod to support my amazon motor and switch to heat set inserts. https://github.com/eMadman/SmartSpin2k/tree/develop/Hardware/MODS/Case%20V2%20-%20Heat%20Set%20Inserts

I'm still working out issues with integration with Roberto on the QZ side of it, but there's been good progress so far!

[doudar]

That's looking awesome! Nice work!

I'm testing a new branch that should have a release shortly. It's much more stable than the last release and reverts to some better ERG code as well. That might help with some issues you're seeing with QZ.

[doudar]

Here's an early binary if you'd like to upload and test it (u:admin/p:admin )
firmware.zip

[eMadman]

Thanks! - should this binary still appear as 1.8.22-develop?

[doudar]

it should show as 1.8.22-december21Updates

[eMadman]

Took a couple of attempts but I got it to flash. It doesn't seem to want to store any settings changes though:

N 227270 HTTP_Server: "Link Not Found: /connecttest.txt"
N 235916 Main: "Stepper power is now 1500"
N 235930 Main: "Stealthchop is now 0"
N 235936 HTTP_Server: "Config Updated From Web"
N 235946 Config: "Writing File: /config.txt"
E 236057 Config: "Failed to create file"
N 236057 Config: "Contents of file: /config.txt"
N 236082 Config: "Writing File: /userPWC.txt"
E 236182 Config: "Failed to create file"
N 236182 Config: "Contents of file: /userPWC.txt"

[doudar]

Most likely a file got uploaded that wasn't named "firmware.bin" and it is taking up all the space in your spiffs partition. The easiest is to reset to defaults, reconnect to the network (so it can download the html files) and then flash again to the test binary via the web interface.

[doudar]

...and here's another new binary. Lots of stability improvement and I fixed a memory leak in one of the newer routines. It should be very stable now. Remember to unzip it before you test.
firmware.zip

[eMadman]

Nice! I'll do some testing tonight. I owe Roberto over at QZ some logs as well, so I'm excited to see how it goes.

RE: the write issues I was seeing, I eventually had to erase the flash on the esp32, but it appears to be taking firmware updates now

[doudar]

Version 1.11.24 just went live on the automatic updates. Please send any feedback you have.

[eMadman]

I couldn't get QZ to update/manipulate resistance on SS2k in my ride last night with Zwift which is the same issue I've been working on.

I did have success pairing SS2k to my IC4 and getting output that way. Compared to when I started this about 2 weeks ago, I think the experience was a solid success. Readings were stable and I didn't experience any latency. Last attempt had zwift fall out of sync not too far into the ride.

I think the readings are way wrong and ended up setting the correction factor around 0.6 to compensate. Else it had me doing 35-40kph on flat roads... I'm pretty confident I'm not nearly that fast. I know that's not a proper calibration but it worked great as a proof of concept. I'm very likely going to go down the path of buying and mounting a power meter in order to pull software-calculated wattage out of the equation. Directly connected to zwift, this worked pretty nicely. It was neat to watch resistance dancing up and down through the ride. Latency didn't appear to be a significant issue either.

[doudar]

Great to hear things are working for you!

Maybe I'll have to grab QZ someday and throw it on an old phone for testing/debugging.

[eMadman]

Well, I'm definitely buying a power meter now. This schwinn/Bowflex mount works brilliantly and the wobble is significantly reduced. Quick video of mount and dismount

Using some very thick command strips right now to hold it up and I know they're adding a lot of flex to the system. Next version will be better suited for zip ties, but will need some rubber/silicon anti-skid dots to stop it from sliding around. This version could be attached more permanently and rigidly with VHB tape, but I was worried it would damage the paint.

Also need to add holes to be able to see the esp32's LED's. For now, you can see them if you peek into the USB port.

Friction fit - tight tolerance on the print - currently using 1mm shim washers to add tightness. Next version will close the gap and get rid of the washers. That should make it a bit more rigid and last longer. The superglue holding the washers in place probably won't last long.

[eMadman]

@rjbutler - You can get the STLs from the MODS folder here. I apologize in advance - I used threaded heatset inserts for the design because I love how repeatable they are. Links are in the readme.md - totally worth having a sack of a hundred or so because these things are incredibly useful and give a stronger screw-together bond than most other fasteners for printed plastic.

I need to rename that folder to IC4 or something and update my bom to include the following:

Will also need:

• 4xM3 screws - I think M3x10 should work, possibly m3x12? As long as it's long enough to go into the threaded inserts, the length doesn't matter.
• 1 pc M5x10mm for the slide on the arm
• 2pc M5x30mm - 1 for the bike mount and another for the case
• 3pc M5 nuts
• 2pc M5x1mm shim washers for the case - if you don't have accurately thick 1mm washers, this can be printed by making a 1mm tall cylinder with a 5mm hole. Shim washers tend to be precision sized to the advertised thickness - much nicer than typical stamped ones. My next update of the case will eliminate these from the BOM because I don't believe it's needed.

For the bike mount, you have two options: VHB tape or something similar OR if you want to protect the paint, you can use the zip tie and rubber sticker approach:

• 6x zip ties for the bike mount - what I did here is fish a zip tie from one end, around the square tube and through the other. Used a 2nd zip tie's ratchet bit to tighten the first zip tie. Trim off the excess. Between the rubber and zip ties, it's a pretty solid mount
• some sort of rubber or silicon non-skid stickers to put on the bike mount to add friction

@doudar - Come on up to Toronto and I'll definitely crack one open with you! I've also shared the idea to a couple of friends and have a buddy lined up to help with testing further - dude's an absolute data nerd and a perfectionist so he'll be all over it from the standpoint of getting it perfect.

[cagnulein]

@eMadman you should consider to post something on the Schwann Facebook group about this! They already know QZ so the step will be close!

[rjbutler]

Thanks @eMadman! I'll see about printing it this weekend. What I have works, but it moves side to side a lot more than I'd like

[eMadman]

@cagnulein - already done! All my spare parts are spoken for by people expressing interest in it. This is great because I haven't had the time I needed to get you updated logs on the bug ticket I have open on the SS2k repo - might get a couple more people helping test the software integration of it this way. I'm hoping to start getting them mailed out before Christmas

[doudar]

@cagnulein - already done! All my spare parts are spoken for by people expressing interest in it. This is great because I haven't had the time I needed to get you updated logs on the bug ticket I have open on the SS2k repo - might get a couple more people helping test the software integration of it this way. I'm hoping to start getting them mailed out before Christmas

Shoot me an email to [email protected] if you need help sourcing parts. I’ve got a decent stockpile and I’m not planning to build any for a while (working on printer mods :) )