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Nita Vesa
Haters gonna hate.
Haters gonna hate.

Nita's posts

What's good software 3D-modeling for 3D-printing?

I've seen several recommendations for 123Design, but apparently Autodesk is shutting it down and won't be updating it anymore, ie. no bugfixes or improvements or anything, ever again, so I gave Fusion 360 a whirl: it's a major god damn disaster. Everything requires cloud, you can't use half the features of it without cloud, even saving files locally can only be done via exporting!

I am planning to get a 3D-printer, I have no experience in either CAD or 3D-modeling, and with Fusion 360 being so terrible I just don't know where to start.

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If you need one yourself or you know someone who'd have use for a cheapish, low-end oscilloscope, like e.g. some beginner who is trying to build their toolkit on a small budget, maybe might fit the bill? It's open-source, too, which is certainly very nice!

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I am building a Raspberry Pi-based small rig for taking close-up photos and video of electronics and to help me inspect solder-joints more easily. It's really crude at the moment, I am still waiting for a better WiFi-adapter, longer camera-cable and a few other bits and bobs, but even as is, it's proven quite handy. I still need to add some LED-lights that I can easily toggle on and off and adjust brightness of and such, too.

I can't afford those big, fancy 500€+ microscopes or such and since I have very little space I wanted something that's small and battery-powered, so I can easily move it around, even when it's running. This little rig also produces very high-quality shots, due to me being in control of how much to compress the images in the first place -- my mobile-phone, for example, can't get anywhere near the quality.

There's really only two downsides: the hassle of having to build it myself (I do really, really wish I could afford a damn 3D-printer!), and the lens has to be manually focused -- no autofocus here. I can live with that, though.

I'm attaching a couple of example-shots I've taken with it in this post.
5 Photos - View album

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I have this 5" HDMI-display for use with my RPi, a knock-off of the Waveshare-one. There ain't any functional difference, except perhaps Waveshare might have used a better panel -- this one has effing awful viewing-angles. Anyways, I finally got fed up with one big issue it has: you can only turn the backlight on and off by a micro-switch on the back of the display, with no way of turning it on or off via software. So, I fixed it by soldering a PNP-transistor over the switch. Then, I wanted reverse logic so I soldered an NPN-transistor to control the PNP-transistor.

It works beautifully (even if my hack itself looks terrible), and as an added bonus, I can now adjust display-brightness via PWM, too.

5 Photos - View album

What would be the best way of powering a 3.3V MCU from a single-cell LiPo-battery, with uninterruptible charging, overcharging and overdischarging protection and buck/boost-operation? I figure buck/boost-operation would be needed because the cell is full at 4.2V, which is too much for the MCU, and empty 2.8V, which is too little for the MCU.

Is there a single IC that can handle that all, or is it better to use separate ICs for managing the battery and for doing the buck/boost, or is there a smarter way of approaching the concept?

God dammit, I'm still a novice when it comes to both programming in general and MCUs, and I really only have experience with the Arduino-environment with only a couple of different MCUs, and I went and made the stupid decision of trying to learn things outside of the Arduino-environment, too.

I've now spent all day long trying to learn about ARM Cortex-M, how to use Eclipse, and programming STMicro's STM32 MCUs using their HAL and CMSIS, and Openocd and and and... ugh, I'm so overwhelmed that all of this feels like jumping off the deep end of the swimming-pool when you can't even swim, and then drowning there.

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For those of us who are excited about the ESP32 I recommend reading and the comments there -- there's a whole boatload of good information there about it.

Personally, I found it really interesting that you can map any peripheral to any GPIO-pin you like at the expense of somewhat slower speed, or you can use the peripheral at the hardware-default pin to get the maximum speed out of that peripheral. Being able to map any peripheral to any pin you like helps a ton if you have a lot of stuff connected to it.

Another thing that I liked was the tidbit that SPI-bus now has an actual DMA-engine, instead of just a FIFO-buffer. The I2C-bus doesn't have DMA, but at least it now has FIFO, unlike ESP8266's software-I2C.

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Anyone got any experience with Seeed Studio's PCB-fab service? ( ) Are they any good, got any comments/thoughts to share?

What if you wanted something more capable than the 8-bit AVR's, but the 50€+ for Zeros and such is way, way out of your budget? Arduino Due would be much more capable, but can also be obtained for much cheaper, but... it's a retired product by now. With Due retired and 50€+ just being too much, there's nothing to go for with the official boards.

Unofficially, ESP32 will be fabulous once it becomes available and the core for it becomes useable, but they just started shipping it today, so it's going to take a while. Of STM32 only STM32F103's seem reasonably-well supported via Roger Clark's Stm32duino, but it's kind of a hacky core because it's built on top of the outdated-and-never-finished libmaple and not everything works well, or even is implemented -- the medium-density F1's seem to work fine, but e.g. hardware-I2C on the high-density F103ZET6 I have is broken (and I have no skills to fix it.) ESP8266 is actually doing pretty well software-wise, but it's quite lacking HW-wise, what with very few GPIO-pins, no HW-I2C or PWM, no proper DMA-controller and such. STM32F407VET6 is cheap on eBay and it sure packs a punch, but support for it is seemingly mostly non-existent.

Is there some core that I am just missing? Or some MCU? Should I just be patient and wait for ESP32 to become a viable device?

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Do you guys like Teensies? Paul Stoffregen seems to have a Kickstarter up for Teensy 3.5 and 3.6 at and I thought to share in case anyone here is interested.

I have no idea personal experience with Teensies, but I hear they're awesome boards and at a quick glance Stoffregen has a lot of libraries and example code available for them, and I hear he has contributed a lot of code to the Arduino-libraries and IDE. I'd like a Teensy 3.6, though I have no idea what I'd even do with all those capabilities. And the fact that its price would be double of what it is on Kickstarter when you add in shipping and customs to Finland :/
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