Led from Hub not turning on

admin

(this is a transcription of a private conversation with a beta-tester, it might be useful to someone else)

[...] we are using the jumper to bridge the pins #2 & #3 from the Hub's JP1, but the LED is no turning on

We tried as a test to connect a K-Ceptor to the Hub and run the Notochord through SSH, but we are getting as a response:

info~[      0] Notochord start @ Wed Apr 10 11:16:22 2019

info~[      0] Verbosity level
info~[    101] I2C adapter initialied on /dev/i2c-1
info~[    101] Starting Armature xml parsing.
info~[    101] Armature Created.
info~[    101] Starting timer. [NODES < 1 , 1 > = 2 | ODR = 50  | Sleep
= 19955us]
info~[    102] Sending rate = 50Hz
info~[    102] Timer started, 2 nodes on scheduler
error~[    102] error switching branch left. Retrying.. (0)
error~[    124] error switching branch left. Retrying.. (1)
error~[    144] error switching branch left. Retrying.. (2)
error~[    165] error switching branch left. Retrying.. (3)
error~[    185] error switching branch left. Retrying.. (4)
error~[    206] Too many errors when switching branch left.
error~[    206] An error ocurred: Can't write to mux

daylanKifky

The output you are getting from the notochord means that it couldn't find a Hub. Since the Hub might not be receiving any power it is expected.

Did you wired the RPi and Hub as in this scheme?
https://wiki.chordata.cc/wiki/User_Manual/2._Setting_up_the_system#Wiring_the_Hub_and_raspberry
Alternatively you can try to connect the [ENABLE] line to the pin 17 (3v3) on the RPi instead of using pin 7 (GPIO 4).

If it is still not working the Led might have been soldered backwards. ~~Is the anode (+) leg of the led on square pad of the D1 footprint?~~ (EDIT) I made a mistake here, see this postto get the correct polarity of the LED

Another problem might be the power bank. Since they are conceived to recharge batteries, some of them might interrupt the power supply when the withdrew current is negligible (and that would be the case for the Hub, with just a led and the Mux in idle state). Could you try using a 5V wall-wart with an USB output instead?
(the ones used to charge smartphones should work)

If none of the above applies I would need some measurements to try to identify the problem.
Please connect the wall-wart to the Hub, unplug RPi and KCs, and use a tester to measure the voltage at

pin #1 of jumper JP1
TP10 (test point near the micro USB connector)

The testpoint TP7 can be used as a reference to Ground.

Let me know how it goes..

Libertario

Having tried evrything else and using 5v 2A wall wart readings are:
pin #1 of jumper JP1 = 3.3 v
TP10 (test point near the micro USB connector) = 5.1 V

daylanKifky

Libertario
🤔 Those values are correct.

Could you please wire everything up, and execute from you raspberry:

i2cdetect -y 1

Libertario

i2cdetect does not detect any devices

daylanKifky

ok, so.. The thing with the led polarity was my mistake.

The long leg of the LED in the Hub goes to round pad of the footprint.
(the reason for that error is that I just found out that the polarity of the led simbol on the K-Ceptor R2.2 design was inverted. I was saying by hearth before, based on the way I remember I soldered the LEDs on the KCs)
my apologies for that!!.

Instead the raspberry not detecting the Hub is what intrigues me.

Could you confirm that the voltage on pin 24 of the multiplexer is 3.3v? and that the Mux chip came soldered on the right position? (with the pin1 mark pointing up)

Libertario

confirmed pin 24 of the multiplexer is 3.3v and
Mux chip came soldered on the right position

daylanKifky

after a long debugging session we found out where the problem was:
The wiring order was correct but the Hub part was upside-down:

Admittedly, on the wiring diagram from the wiki it wasn't really clear which side was up or down. I've now uploaded a new one
https://wiki.chordata.cc/wiki/User_Manual/2._Setting_up_the_system#Wiring_the_Hub_and_raspberry

sully

So I've got a fully built Hub and a fully built K Ceptor and I'm getting the same exact branch error. My LED on the Hub and my K Ceptor are on and look good, proper power and ground on the mux chip and test points, quadruple checked the pin wiring diagram, tried powering via hub and direct 3.3v and each method provides power fine and returns the same results. Default XML file hasn't been tampered with at all.

I2C detect command brings up nothing either. Anything that comes to mind? I did solder the RGB LED on the hub (cathode facing the correct position), would that cause any SDA,SCL interference being that it's not supported yet? I haven't looked far into testing my K ceptor yet being that this issue starts with the Hub if I've read this thread correctly. I configured my K Ceptor with the 102k resistor on r6 so it reads as 0 and is attached through port 1. Attaching a picture of my hub and k ceptor just in case anything jumps out at you.

daylanKifky

sully

I moved your part discussion to this other thread , since it's significantly different from the original problem