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Hacker News was talking about this little device, which looks cool. I can't say I'm that into MPUs (like Rasp. Pi, Beaglebone or vocore), but there's a degree of niftyness to them.

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submitted 6 months ago* (last edited 6 months ago) by dragontamer@lemmy.ca to c/microcontrollers@lemux.minnix.dev

Editor's note: I can't post pictures from my Lemmy.world account. I presume that recent trolling-attacks vs Lemmy.world have to do with this restriction, so I'll use my Lemmy.ca account for this post.

Today is a "Sidenote" for my "Beginner Series", because its not a particularly scheduled discussion point. I was browsing the internet for some documentation when I found Microchip's Signal Chain Design Guide.

Yes, this is marketing material. But its well written and covers many important concepts for beginners. Again, the PDF is here: https://ww1.microchip.com/downloads/en/DeviceDoc/21825g.pdf

At the crux of the 'Signal Chain' is the following diagram:

Many, many applications can be simplified down to this loop. Sensors provide a signal of some kind: changing voltages or currents as real life events happen. Temperature changes resistance and/or voltage of a thermocouple, pressure changes resistance of resistors as well. More complex sensors like IR Photodiodes will change their current due to the presence of light. (and that IR Photodiode may itself be encoded information: with lights turning on-and-off associated with machinery RPMs).

Whatever the "sensor" is, it may need analog processors to condition. OpAmps are the most common analog processor, but instrumentation amps, differential amps, and sometimes even raw BJTs are used for this step (when high-frequency is needed, such as amplification of radio signals). There's a side note here about digital-potentiometers and their ability to calibrate analog bits of your circuit, but calibration can be skipped if you don't care much about accuracy.

In particular: whatever your "signal" originally was needs to be converted into a voltage of the appropriate size for your ADC. For example, a capacitive touch sensor can track the human-body (fingers) moving across different electrical pads. This "signal" is watching for the change of capacitance over different electrical lines. But "capacitance" isn't voltage. Instead, you need to inject small amounts of current into the various pads while measuring their change-of-voltage over time, which converts the "change of capacitance" into a "change of voltage" formula, thereby allowing later stages to operate upon your data.

Once the signal is processed to appropriate levels of voltage and/or current (or if you're lucky enough: the raw signal is good enough without need of preprocessing), then you can feed it into an ADC and digitize the signal.

Once the signal is in digital form, you write a computer program to analyze and manipulate the data. For many, the data will remain in digital form perpetually, sent out over WiFi, Bluetooth, or perhaps to a MicroSD card for recording. But for others, the job is not done yet. The combined sensor data goes into an algorithm to determine actuator outputs.

Those actuator outputs leave in either PWM form or DAC as an analog signal directly. Alas, microcontrollers usually have weak pins, so output processing and amplification is needed to increase power levels to appropriate voltages and/or currents.

Finally, those voltages and/or currents affect an actuator. That could be a servo, a motor, LEDs to blink or really anything.


While these steps are individually pretty simple, as a whole they constitute a pattern and architecture that matches a huge number of electronic designs. Your thermostat (temperature sensor -> microcontroller -> turn furnace on or AC on). Drones (accelerometers to measure bearings in space - microcontroller -> motor controls), motor controls (sense current through motor to estimate torque -> microcontroller -> BLDC Motor signals), and more.


This page summarizes the sensors available from Microchip. And remember, this is just one company. There are plenty of sensors available around the world in many other forms.

As far as actuators... Microchip doesn't make too many of those. But motors, speakers, MEMS, refrigerators... anything you can hook up to electricity is something you can control with a microcontroller.

[-] dragontamer@lemmy.ca 2 points 6 months ago* (last edited 6 months ago)

I realize this story is about the ESP32-S3, but the OTHER board discussed in that article is way more intriguing to me.

This, in turn, followed on from the Metro M7, based on NXP's i.MX RT1011 "crossover microcontroller unit" — offering a much more powerful take on the Arduino UNO form factor, which itself has since been updated with the release of the modernized UNO R4 Minima and WiFi.

Wait, wut? They've got an i.MX unit? Well now I'm super intrigued. I've posted about the difference between Microcontrollers and Microprocessors in my guides. But the i.MX series from NXP tries to toe the line inbetween the two categories. A Cortex M7 though is still solidly "Microcontroller" to me, but any i.MX will intrigue me because its specs are incredibly high for a uC (or incredibly low-power for a uP).


With regards to Arduino form factor... the size roughly compares to 3x AA NiMH cells or larger 18650 Li-ion cells. Its a good size for portable applications, though a bit larger than something you'd reliably put inside a pocket (big pockets can probably fit Arduino form factor + batteries though).

Adafruit themselves seem to be most interested in the Cosplay-electronics community, so something like this would be a wearable that you'd hide in your costume somewhere. (Ex: controlling the lights to an Overwatch costume or other "techie" video game costume that needs a lot of lights, fiber optics, and the like).

In any case: that's three boards with three different sets of capabilities: from the lowly RP2040, to ESP32-S3, to i.MX Cortex M7 "crossover" chip.

[-] dragontamer@lemmy.ca 2 points 6 months ago

I hate this setup.

Rasp. Pi Pico W has a Wi-Fi card. Cool. The WiFi connects to your local WiFi network, which connects to your ISP, which connects to the internet, which connects to ntfy.sh. NTFY.sh then creates a push notification over Apple and/or Android, then finds your Phone, likely realizing your phone is currently in your WiFi network. It then sends a message to your ISP, to send a message to your WiFi network, which sends a message to your Phone and you finally get the alert.

Its probably the easiest way to get things done, but a bluetooth alert and/or Wifi-direct alert of some kind would be better. Phone APIs don't seem too keen on WiFi / Socket servers however. Bluetooth would likely be a better solution, but involves pairing and other such noise to complicate the process.

Hmmmmm. I see that ntfy.sh is the easiest way to bridge it all together. But that doesn't mean I have to like it.

[-] dragontamer@lemmy.ca 1 points 6 months ago* (last edited 6 months ago)

Old news.

https://www.cnx-software.com/2019/02/21/stmicro-stm32mp1-cortex-a7-m4-mpu/

This happened in 2019. STM32MP2 release is coming soon, so we're well on our way to having the 2nd generation of STM32-microprocessors.


I'm mostly a MCU fan. MPUs are awesome too, though the gross complexity increase makes my head spin. Supporting "proper" DDR2 and 512MBs sounds awesome though, my personal VPS for years has always been just a 512MB instance because that's enough for personal websites and simple Linux tasks.

512MB DDR2 on a single-core ARM A7 is exciting to me. But... in a way that feels forbidden, too complex for me to truly get into and try to use. I'd probably just buy things like Beaglebone Black ($50 at the moment), or Rasp. Pi (if it ever comes back to a good price).

[-] dragontamer@lemmy.ca 2 points 6 months ago

That didn’t fit with his limiting how many tweets users are able to view.

The theory behind that is that Twitter failed to pay for their web-services and needed to suddenly cut traffic, otherwise they'd be shutdown by Amazon / Google.

After Twitter paid Amazon/Google, they raised the tweet view-limits appropriately, but the damage was already done.

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submitted 6 months ago* (last edited 6 months ago) by dragontamer@lemmy.ca to c/microcontrollers@lemux.minnix.dev

Github repo for microcontroller-automation of playing Pokemon.

Information on how to electrically interface with the Switch, analyze the screen to look for various triggers, and otherwise automatically play "Pokemon" games. Using Arduinos, or Teensy, or other microcontrollers.

The microcontroller bit controls the Switch itself, sending USB commands through the Arduino-Leonardo to the Switch, effectively having the Arduino-Leo automatically play the game for you.

More advanced automations include the PC computer to analyze the screen and perform more complex calculations. But the microcontroller bits are probably interesting to this community!

[-] dragontamer@lemmy.ca 2 points 6 months ago

Microcontroller ADCs still have a bad reputation compared to "hardcore" analog designers, but STM32 isn't bad in the great scheme of uCs.

https://hackaday.io/project/188051-rpscope

Here's the original project, and with a circuit layout closer to what I'd expect to be typical. However, notice that the STM32 contains all the parts that are in the rpscope: STM32 has an ADC (albeit a slower one), multiple OpAmps (albeit with lower accuracy), and a microcontroller (albeit with less RAM than the RP2040).

Shrinking and consolidation is the goal for these devices, leading to far cheaper designs with possibly better reliability (now that its all put together in one package). Of course, the specs are far weaker on the STM32 rather than dedicated ADCs, but you can see the size, cost, and power/watt difference by just looking at this thing.

[-] dragontamer@lemmy.ca 1 points 6 months ago

Test post for my alt to be promoted to moderator.

[-] dragontamer@lemmy.ca 2 points 6 months ago

8051 is a legend alright.

[-] dragontamer@lemmy.ca 2 points 6 months ago* (last edited 6 months ago)

Hacker News was talking about a relatively low battery life out of the box. The device probably needs more aggressive sleep software.

https://news.ycombinator.com/item?id=37054361

This is my alt account because Lemmy.world is having DDOS issues the past couple of days.

dragontamer

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