Tuesday, July 30, 2019

Wltoys 12428b (part 3; steering reversed)

From my previous post, the steering on our new Wltoys 12428b RC car is reversed..

This is bugging me now.  Part of me i am sure is quite happy to have a problem to fix.. at any rate, a quick google netted me the following pieces of advice, in no particular order:
  1. old4570 says "..The Tx has no reversing , so you will need to flip the Steering servo.."
  2. SOUL FORCE QUADS offered "..I'm just guessing here...) WITH CAR & TRANSMITTER TURNED OFF - Press & hold the "mode" button on the transmitter... then turn on transmitter and release mode button. Power on car, turn wheel to see what happens. Repeat up to 4 times if necessary... Good luck!!!
  3. Some reviews on a replacement steering servo on bangood, warning "..Compared to original WlToys 12428 - this one is inverted! Designed good, works great but I had to replace 2 wires in remote to get it working correct (my RX doesn't have inversion button)..."
Meanwhile i had already pulled the remote apart and i can see 3 wires (red, blak and white) going from the PCB to the steering wheel.  I can't be sure if reversing the polarity of the wires will help, and as yet i have no oscilloscope.. (hehe).  I also can definitively say there is no hidden servo reverse switch there..

So I put the remote back together and tested it functions as normal, ok, i didn't make it any worse :) Then tested the 2nd option, but no go, even tried an extra time!  So now I'll read up on "flipping steering servo".
  1. Someone else said i should by a servo reversing cable..
  2. Others have suggested re-soldering the servo connections internally.
.. but i really need to go to bed now .. ;)

PS: We bought two of these cars, the second one didn't have the same issue.. I had to check it several times to be sure i wasn't going insane.. weird.

Monday, July 29, 2019

Wltoys 12428b (part 2; it arrived!)

 My somewhat ignorant review so far (1 day..), first the awesome stuff:
  1. The headlight and tail lights are awesome ;)
  2. It's sufficiently heavy, the build quality is very good.
  3. My boy loved the way the rear suspension worked.  Smooth and powerful.
  4. It goes slow well and can be used indoors if you're careful.
  5. The steering servo seems powerful, if a little fast at speed.
  6. I like the look, but i can't wait to spray paint it all orange or something.
Then the stuff I've fixed:
  1. The front suspension didn't rebound, but it was adjustable.
  2. The rear diff is metal but it didn't have much grease in it.
  3. I set my imax b6ac v2 charger to liPo instead of liIon which overcharged the battery by 0.2v, enough for the car not to start the first time.  I fixed me being shite .. ;)
  4. There was a squeaking noise coming from somewhere, i thought it was the rear diff but not that, so i sprayed some silicone lubricant on the drive shaft at each universal joint, but the culprit was right where it exits the transfer case (near the centre of the car).
And finally the broken stuff:
  1.  The steering is reversed.  Maybe my brain is backwards so i didn't say anything, but my boy is the same.  Can't find a switch anywhere to reverse it and so short of replacing stuff* I can't find any way to fix it :/
* in addition to replacing the transmitter as best i can tell the receiver is part of the ESC and from what i've read the servo is an incompatible 3 wire type which doesn't work with most hobby grade stuff.

Wednesday, July 24, 2019

iMAX b6acv2 battery charger (part 1: logging and graphing)

I purchased a iMAX B6AC V2 multi-chemistry battery charger for use with RC cars, and immediately installed the official application under Windows.  It allowed me to control various functions as per the display and buttons on the actual device, and in addition offered realtime graphs.  They worked!  however, it was immediately obvious that this would never do.  I couldn't save the graphs, nor could i access the raw data, and starting a new charge/discharge resulted in the previous data being destroyed.  wtf!!

I went on a bit of a hunt and found Logview and a reboot called Logview Studio.  I installed both on Windows.  Logview didn't recognize the charger at all.  Logview Studio did, however when it came to recording data nothing actually appeared.  More concerning was that it seems development stopped with the most recent versions for both being released around September 2014.

So then went to my old faithful, why did i ever doubt you, the open source community.  Pretty quickly i found GNU DataExplorer and being a Java app it ran ok on Windows.  On OSX i need to do some rubbish to allow me to access the device via USB, so i shelved that.  Under Linux (Ubuntu 18.04) it's sufficient to be root, although with the correct permissions i shouldn't need to sudo.

Here's a pic of me proving to an ebay vendor that their 1800mah battery really isn't.  Leave positive feedback they said..!

Tuesday, July 09, 2019

Wltoys 12428b (part 1: how we chose)

So after playing with a toy grade RC car that my boy was given, I decided I'd like to get into the hobby some more.  If you've been here you know how hard it can be to choose, so maybe this might help someone.  My decision was based on a few criteria:
  1. Had to be initially cheap (we paid ~$120AUD delivered), I wasn't sure we were going to stick with this hobby.
  2. It had to be able to be fixed and have parts readily available.
  3. It has to have an active modding community, from which i can pick an upgrade/mod path if required.
  4. Has to be fun to play with outside but not be ultra fast because we're just going to crash it otherwise.
  5. Generally look tough and not like a toy.. yeah.. ;)
After much consideration i decided to purchase a pair of Wltoys 12428b 1/12 4WD RC buggies, one for me and one for my boy.   It's the successor to what seems to have been a wildly popular RC car the 12428.  I think this model looks better and has more metal parts as well.