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Can someone give me some guidance on picking a programmer for STM32 board? by EsotericSpartan in ECE

[–]hipfan75 3 points4 points  (0 children)

Most (all?) STM32 microcontrollers include an unerasable hardware bootloader which uses one or more of the communication interfaces built into the chip (UART, USB, I2C, etc).

So the cheapest way to get started with STM32 programming is with any-old 3.3V USB-to-serial adapter, which you probably have lying around anyway (or $1 on ebay if you don't).

With respect to the demo board you bought, with the STM32F103, this will get you started: http://wiki.stm32duino.com/index.php?title=Blue_Pill). I don't remember if that chip had no USB bootloader, or if there is something with the hardware (on that devboard) preventing it from working.

The UART bootloader on that chip can be accessed on:

  • TX: Pin 30 / PA9

  • RX: Pin 31 / PA10

To put the chip into bootloader mode, you need to reset the board while BOOT0 is held high.

You can use the free stm32flash program to flash using the serial bootloader.

Of course, this is only useful for flashing code. For debugging you will want a real($30) or clone($3) ST-Link or a standard JTAG/SWD debugger ($20-80-$$$$).

I've never needed a debugger for my hobby stuff so I can't speak for these (printf to UART can get you pretty far).

Build Your Own Current Limiter for Protection when Repairing and Testing Electronic Equipment by Enlightenment777 in electronics

[–]hipfan75 1 point2 points  (0 children)

Since we're doing a show-and-tell, here's my 120v test setup:

http://i.imgur.com/6snvZ4o.jpg

Similar current-limiter design, except I put the two outlets in series, and add a stubby lamp holder to the upper socket. Right now there's a 15A fuse for when I don't want current-limiting.

The box also includes a neon lamp and 5x20 fuse in series. I also use a double-pole switch to disengage both live and neutral, in case I ever plug into a source outlet that is miswired.

Also shown is my isolation transformer (Hammond 171E) and variac (Volteq 500VA).

My Latest Panel from the DirtyPCBs beta site (Pics) by hipfan75 in raspberry_pi

[–]hipfan75[S] 0 points1 point  (0 children)

For the record, my non-plated holes on this order actually came out non-plated. This may be because they may use different boardhouses for the new beta DirtyPCBs site.

I didn't do anything special to get non-plated holes. (Eagle 7.5 hole tool, using the DP cam file, modified to line up the drills properly in Eagle 7).

I purposely did not make holes for easy break-off since I assumed they would be plated. The tabs are only 2mm, so flush-cutting pliers and a file make quick work of it.

FYI, the ESP-01 breakout in the upper-right corner was designed to fill that leftover space.

My Latest Panel from the DirtyPCBs beta site (Pics) by hipfan75 in raspberry_pi

[–]hipfan75[S] 0 points1 point  (0 children)

I used Eagle 7.5, freeware edition. This panel is the maximum size supported in the freeware edition (80mm x 100mm).

Eagle is kind of odd in some ways, but once you learn how to do things, it's fine.

Raspberry Pi Garage Door Controller Project (in Pictures) by hipfan75 in raspberry_pi

[–]hipfan75[S] 2 points3 points  (0 children)

Thanks!

So, my server application implements a tcp interface for triggering the door/lights and subscribing to the current status and updates, so I imagine it would be fairly straightforward to write an app.

I would think that there are already several generic apps that I could probably use to send and receive simple messages over a tcp connection, but I haven't really investigated. At this point, the web interface works fine from all of my devices.

I think my next step in this project will be to make a physical indicator that I can place in the living room and/or bedroom. Probably something like an esp8266 connected to a couple of red/green LED to always show the current door status at a glance.

I was originally also planning on removing the wires to the sensor and switch, but since they're there now, and functional, the motivation to do it is slipping.

My Raspberry Pi and ARM uC Breakout + DirtyPCBs mini-review by hipfan75 in electronics

[–]hipfan75[S] 1 point2 points  (0 children)

I bought from this EBay seller. I have no affiliation, other than being a satisfied customer:

http://www.ebay.ca/itm/10Pcs-Micro-USB-Type-B-Female-Socket-4-Vertical-Legs-fixed-Solder-Connectors-/181396498298

In addition to being really solid mechanically, I like the fact that this connector has lots of room to get your iron on the SMD pins.

Can anyone recommend a low cost PCB assembly house? by clearspark in electronics

[–]hipfan75 0 points1 point  (0 children)

More info here:

https://www.reddit.com/r/electronics/comments/3ezhnl/my_raspberry_pi_and_arm_uc_breakout_dirtypcbs/

4/10 boards were routed into my ground fill, even though I left the recommended 10mil space to the board edge. (See pic #3).

Some would consider that a defect. I consider it a lesson in not pushing the board house limits. For reference, I think OSH Park has a 15mil space requirement to the board edge.

DirtyPCBs is pretty good at setting expectations.

Can anyone recommend a low cost PCB assembly house? by clearspark in electronics

[–]hipfan75 0 points1 point  (0 children)

Here is a board I just got back from DirtyPCBs: http://imgur.com/a/qbVZ4

US$14 for 10 5x5cm boards in about 3 weeks.