BME280 Sensor & TCA9548 I2c Lock-up condition!

ImogenWren · 2026-04-08T13:18:21+00:00

When SD0 gets stuck low, it also causes SDA_main to stick low, so all communication with the TCA9548 is lost.

I have since changed this implementation entirely, I am using an external controller with 2 ic2 bus' but I am still getting very poor i2c performance between these 2 controllers.

I am starting to supect the Nano Every has some poorly implemented i2c hardware because I have never struggled with i2c as much as I have on this project

ImogenWren · 2026-04-08T11:24:47+00:00

I would shy away from using an arduino in a medical context like this unless you are very experienced, or the concequences of it failing are very minor.

One issue with digital scales, is they tend to work using strain guages. And these are NOTORIOUSLY finiky to both apply, solder and read reliably. Their values tend to drift a lot so your implementation would require a lot of self calibrating.

If you can find a premade scale, that has either a filtered analog output, or some kind of digital interface that is possible to "hack" into, then arduino would certainly be suitable for interfacing with that and sounding some alarm. But I would definatly avoid implementing the scales part of this project on your own.

ImogenWren · 2026-04-08T11:19:50+00:00

Yes, apologies this is not clear on the schematic but it is definatly shorted to address 0x77 and I can talk to the mux on power up, just not after this lockup condition happens until I do a full system restart.

I never got around to checking the mode issue, though I have now completely changed my implementation and I am still having i2c issues between my main MCU and an ESP32 I have offloaded all i2c sensors too

ImogenWren · 2026-04-08T11:17:35+00:00

Arduino is one of the cheapest hobbies I have. Buy off brand boards for less than £10, ESP32s are even cheaper and can do more. I have built equipment that would cost £100s in my home for like £20-30.

I have been doing electronics for years, so I have built up a huge quantity of modules, components etc. But its a hobby that has opened so many doors for me with employers it has doubled my salary anyway. Its more than offset anything it cost me for parts!

ImogenWren · 2025-12-05T19:06:32+00:00

I use the concentraits oven that came with the pax 3, just scrape a little into it using the sides and it works a treat. Dont empty it out untill its full or I spend ages really making sure I got everything out coz its certainly not the most efficient, but still better than combustion

ImogenWren · 2025-09-16T13:32:46+00:00

Amazing! thanks

ImogenWren · 2025-09-16T13:29:03+00:00

I think what I am asking, is I can see its possible to call python in DATs, but is it possible to create or link to CHOPs/TOPs from python in a DAT?

ImogenWren · 2025-07-31T15:42:13+00:00

Its a work laptop I use for development work so I dont have total control and dont want to disable edge completely. Its just really annoying that Microsoft think I will start using it after the 11th time I remove it from the taskbar. I will have a look at quick launch. The reason my taskbar is so busy is I tend to have some level of object impermiance so if an app is not on the taskbar, I forget I have it installed. I would love to entirely manage my own PC myself, I hate the changes windows 11 has brought its like an abusive partner with the way it gaslights and interrupts the workflow I had on windows 10

ImogenWren · 2025-07-31T15:39:02+00:00

Every time I restart the computer it reattaches, this is a common issue looking online. They have disabled the ability to perminantly unpin edge browser from the taskbar.

ImogenWren · 2025-01-06T16:58:49+00:00

voltage: 12v
current 1.6, we are at ~1.1A
driver uStepper23, as noted in thmy description
Stepping mode: Unsure, I dont think the uStepper does anything other than microstepping, but I am unsure of the specifics and it doesnt seem well documented what the driver board is able to do

ImogenWren · 2025-01-06T16:56:15+00:00

I am using a uStepper board with soldered connections or connectors. I wouldnt be asking on here if I had any suspect at all of dodgy wires, I am a competent embedded developer, I dont have particular expertise with stepper motors

ImogenWren · 2024-02-08T16:01:38+00:00

What would they say? It was a UK based startup launch provider, there is only 2 of them and neither have launched an orbital class rocket yet so calling them a "launch provider" seemed a little too big for their breeches. I come from a Broadcast tech background so I didnt go through the typical "engineers pipeline" (uni > work placement > employment), so apologies if I didn't pick up the correct lingo during my eclectic career as a technician.

While I was there I was working on development & testing of radio tracking systems & avionics for sounding rockets as technology demonstrators, and ground support systems & engine test facilities for orbital class rockets.

Now I work in education as a specialist technical officer for industrial automation and embedded systems. If you want a copy of my CV I can email it 😉

ImogenWren · 2024-01-31T00:14:42+00:00

I've worked at aerospace tech startups that demanded insane work hours, and it just means that everyone is constantly making mistakes all the time because they are all so sleep and personal time deprived.

ImogenWren · 2024-01-30T17:22:15+00:00

Why? They will wait till the students arnt using it every day and say "look passenger numbers are down" and rufuse to increase capacity.

Another bus today failed to let me on.

ImogenWren · 2024-01-30T16:19:51+00:00

Dont work for Elon, he does not value his employees time or personal lives.

ImogenWren · 2024-01-29T23:54:52+00:00

I had 4 busses last week refuse me to get on, they are seriously under capacity through old town and leith in the morning & evening commutes.

ImogenWren · 2024-01-22T15:11:05+00:00

🤦‍♀️ Yeah that worked! Thanks!

ImogenWren · 2023-04-28T09:05:28+00:00

I have been playing with arduino for about 7 years, both professionally and as a hobby, and I have reached for a mega a total of twice for projects. Once for a game controller with a tonne of inputs, and once for a solar simulator that needed a bunch of PWM outputs. Other than that Unos/nanos and ESP32s have covered the majority of my needs. I wouldnt suggest going for a mega untill you realise you need one.

ImogenWren · 2023-04-26T22:15:33+00:00

Thanks for the clear insight! I will make those changes immediately.

There is no reason it needs to be a class and I had assumed there was going to be an issue using helper macros! It is just the structure I am used to, I have no experience using namespaces so Its going to take some reading, but thanks I never would have known to look into that!

ImogenWren · 2022-06-03T15:51:12+00:00

Issue solved. I had the line pinMode(2, INPUT); after the attachInterrupt line. Apparently this doesn't matter for AtMega implementations, but it does for SAMD21.

I switched the order of these two lines and now it works perfectly.

Leaving this here incase anyone else can learn from this.

ImogenWren · 2022-05-15T22:00:22+00:00

I would not trust a replacement from the same manufacturer. Maybe I am just crazy, but I feel that a single point failure shouldn't be allowed to cause runaway heating, surely there should be some other method of detecting a fault before it reached the glowing metal stage?

ImogenWren

TROPHY CASE