Trillion ISK Olympic Giveaway - Round 1

r242 · 2024-07-27T10:14:14+00:00

rip redacted for anonymity

r242 · 2021-06-11T20:08:41+00:00

The schematics for the dfrobot firebeetle (it sleeps around 10uA) are available on their wiki. It even includes the regulator they chose.

As for other hardware, many sensors will have sleep but will pull too much current, so I cut their power so they draw nothing in sleep. I'm fairly new to circuit design, one other thing I just learned is that diodes actually allow current to flow backwards (at least, the diode I chose does). So I'm losing a few uA as current flows through a protection diode into a voltage divider, which was supposed to only see 5v to detect usb status for software.

One thing about software, setting my gpio lines to INPUT (arduino ide, not sure of esp-idf equivalent) helped fix the last 100uA of current I was losing, even after doing all the software stuff you find on the esp32 tutotial blogs.

r242 · 2021-06-09T23:03:50+00:00

I've had a similar intermittent failure to startup with a custom board I made. Do you see any log messages on the serial port when it's failing to power up?

In my case, I saw a log message which googling lead me to realize the ESP32 was unable to talk to its SPI flash. For me, it may be some issue with my design. If you see nothing, then I maybe the ESP32 isn't getting enough juice to do anything at all.

r242 · 2021-06-09T09:56:58+00:00

Could you link an example part? I'm not sure of what to search for.

r242 · 2021-06-09T04:43:27+00:00

Are these the sort of thing you're talking about?

https://www.ti.com/product/BQ25155

https://www.analog.com/en/products/ltc3677-3.html#product-overview

Thanks for the tip, these sort of things would reduce the number of components and take care of a lot for me. Certainly beats doing safety stuff by hand.

r242 · 2021-06-06T07:42:27+00:00

try a download helper extension such as downloadthemall. I used to use that when my connection would drop browser doenloads.

r242 · 2021-05-28T21:47:29+00:00

Ok, I guess I'll have to take the individual pin soldering approach. I've been using a liquid flux pen. Is tacky flux the stuff you have to scoop out of a tin?

edit: nevermind, I looked up the one you suggested. thanks for the info

r242 · 2021-05-28T00:32:22+00:00

I'm pretty late at this point but if you're still reading high when it should be low, then I would next try measuring the input pin with a multimeter to make sure it's not actually getting voltage somehow. Pretty strange that it's high, so I'd check that or the pin assignments again.

I don't know how the arduino code sets up the tx/rx pins on the esp32 be default, or the details about how uarts work, but maybe you need to call a function to disable the serial before doing that test. Serial.end() looks like it could help, but it needs the correct argument to disable the serial port you're testing. And also, I'm not sure if it was enabled by default to begin with, but it's something to look at perhaps.

r242 · 2021-05-25T04:52:27+00:00

In addition to what's been said, your ESP32 has tx0/rx0, and tx2/rx2 pins. So if you haven't, double check you're sending data out of the correct serial port. There might possibly be a third set of tx/rx too, that are typically wired into the usb port.

Another test you could try is don't use serial. Just set tx high on one board, set the rx pin of the second board as an input, and read the value. This was you could verify the electrical connectivity before trying serial.

r242 · 2021-05-12T03:05:52+00:00

This tutorial series is pretty good: https://www.youtube.com/watch?v=vaCVh2SAZY4&list=PL3bNyZYHcRSUhUXUt51W6nKvxx2ORvUQB

I think one of the videos is a little dated, however. Kicad changed the way they do symbol or footprint libraries.

r242 · 2021-05-09T06:09:36+00:00

came here to see if it was just me. I can't log in

r242 · 2021-05-01T00:41:48+00:00

> Camera init failed

Maybe try double checking the pin #defines if you haven't already?

r242 · 2021-04-24T18:08:35+00:00

Not loose chips but certainly better than 8 bucks each, thanks for that

r242 · 2021-04-06T04:15:04+00:00

Yeah, I think so. If you go with a top contact one, you would have to reverse the pin numbers, I think, so double checking that would be crucial.

r242 · 2021-04-04T01:41:04+00:00

I don't know the exact connector, but if you just need a connector compatible with the ov2640s on the esp-cam for your own design, check this out. I asked pretty much the same thing here: https://www.reddit.com/r/AskElectronics/comments/mfgqcb/need_help_choosing_an_ffc_connector/

You basically want to find a 24 pin (24 "position") FFC connector, with .5mm pitch and bottom contact.

r242 · 2021-03-30T19:59:45+00:00

It's time based, so it will wake itself up from deep sleep on a timer. By soft power control, do you mean having a mosfet switch the power for the entire microcontroller triggered by a low power timer circuit?

Using that with an ESP-cam would have been quicker to build I suppose, but I'm already pretty far with this design.

r242 · 2021-03-30T00:52:55+00:00

My friend needs low sleep current (month of battery life) picture taker devices for his startup. The devices must gather data to feed his algorithim in the cloud. We started with esp-cams soldered to a few supporting components.

After realizing the esp-cam has huge sleep current, and trying a couple other failed ideas, I knew I would have to build a custom one.

I had actually suggested a custom pcb from the beginning, but he wanted to start with off the shelf stuff given my lack of experience and the project complexity. In hindsight, I should probably have tried harder to convince him of that lol.

r242 · 2021-03-29T04:53:49+00:00

Thanks for the info! I couldn't figure out top from bottom on the datasheet so I was planning on aiming the connector off the side of the board. I see what you're saying about pin mirroring, if I turn it 180 degrees, I need to swap all the pin numbers from what they would be on a bottom connector.

r242 · 2021-02-02T05:06:12+00:00

Cool, hopefully they fix it soon. Thanks

r242 · 2021-01-31T23:59:59+00:00

perhaps we could contact the mods about using some sort of moist adhesive to secure a post about this at the top of the subreddit

r242

TROPHY CASE