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We made an open source ESP8266 dev board for makers

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Re: We made an open source ESP8266 dev board for makers

#121

Post by konschubert »

rohansingh wrote: post #115
konschubert wrote: post #75

Earlier quoted context omitted.

I am sure this is something will be able to answer: I need to build a custom board for an ESP32 which should support low-power deep sleep and which should contain some additional circuitry (is that what you call it?) to drive an Eink display. Basically this[1] board, but a different shape and better low-power sleep properties. If I wanted to design this board myself, how long would it take to learn this? Are there go…

A good place to start would be reference schematics from Espressif for their dev boards, and schematics from open ESP32-based boards from other vendors. Check out esp32.com for a list of boards. With those schematics and KiCAD, you should be pretty much set. Take an hour or so watching KiCAD tutorials, it'll be worth it. Also, spring for an ESP32-WROVER-KIT and use it to prototype with a dev board. That kit also supp…

Thank you, this is really helpful.

Re: We made an open source ESP8266 dev board for makers

#122

Post by andruby »

fullstop wrote: post #114
andruby wrote: post #77

Earlier quoted context omitted.

For the software part, WLED [0] really does just about anything you’d want to do with those led strips. I drive the wemos d1 and led’s from a 12V battery with a 12-5V stepdown converter. I attach the 5V to the esp and the led’s. The 3.3V logic level works on the first led and is repeated at 5V to all subsequent led’s. [0] https://github.com/Aircoookie/WLED

Apparently 3.3v doesn't always work with the strips, and newer ones are less likely to work, especially if you're working with a lot of lights.

My assumption was the each individual led chip will re-transmit the signal to the next led, which in effect will turn the 3.3v signal into a 5v signal between the 1st and subsequent leds.

The power lines do sustain voltage drop over longer sections, so you'll want to add extra power every few meters.

Re: We made an open source ESP8266 dev board for makers

#123

Post by rohansingh »

konschubert wrote: post #121
rohansingh wrote: post #115

Earlier quoted context omitted.

A good place to start would be reference schematics from Espressif for their dev boards, and schematics from open ESP32-based boards from other vendors. Check out esp32.com for a list of boards. With those schematics and KiCAD, you should be pretty much set. Take an hour or so watching KiCAD tutorials, it'll be worth it. Also, spring for an ESP32-WROVER-KIT and use it to prototype with a dev board. That kit also supp…

Thank you, this is really helpful.

Sure thing. By the way, I should have said esp32.net, not esp32.com. The latter is the official discussion board, but the former is an unofficial reference site that's incredibly useful.

Re: We made an open source ESP8266 dev board for makers

#124

Post by R0b0t1 »

tripletao wrote: post #63
R0b0t1 wrote: post #55

Earlier quoted context omitted.

Test and measurement supersedes intentional emission. If it were the other way no development boards would get sold, especially necessary things like low volume engineering samples. Should a one-off need certification before it can be transferred to the company that contracted the work to build it? No. If you have never sought certification know that it is quite expensive. What seems to matter the most is if anyone a…

> Test and measurement supersedes intentional emission. On what authority are you claiming this? The language LeifCarrotson quoted refers only to digital devices, and the language I quoted above says plainly that a digital device must be an unintentional radiator. To be clear, I believe selling their dev board is fine, but it's fine in the same way that driving 60 mph in a 55 zone is fine. Anyone selling an intention…

On what authority are you claiming otherwise?

My opinion comes from experience and getting things certified but also common sense and observing enforcement patterns (the latter of which is most important until they overstep and get challenged).

Go back to my example: Does a one-off product need to be certified to be transferred to the people that paid for it? Keep in mind, best case, this will add a roughly >$10k fixed cost to the sticker price.

It's a general principle in common law that the law makes sense. The popular, sophomoric, and extremely conservative interpretation of the FCC rules makes no sense by way of being extremely costly for no discernible benefit, either to the seller, the buyer, or the economy at large.

Re: We made an open source ESP8266 dev board for makers

#125

Post by fullstop »

andruby wrote: post #122
fullstop wrote: post #114

Earlier quoted context omitted.

Apparently 3.3v doesn't always work with the strips, and newer ones are less likely to work, especially if you're working with a lot of lights.

My assumption was the each individual led chip will re-transmit the signal to the next led, which in effect will turn the 3.3v signal into a 5v signal between the 1st and subsequent leds. The power lines do sustain voltage drop over longer sections, so you'll want to add extra power every few meters.

Right, that is exactly how it works. If your signal to the first IC isn't perfect, and it isn't with a 3.3v signal, you can end up with incorrect colors or shifted patterns.

As you add more LEDs you have a greater chance of one at the end not lighting up or having incorrect colors throughout the string.

0.7 * 5v == 3.5v, and 3.3 < 3.5. You're out of spec for the part and can't expect it to work reliably.

Re: We made an open source ESP8266 dev board for makers

#126

Post by na85 »

05 wrote: post #97
na85 wrote: post #79

Earlier quoted context omitted.

>If I wanted to design this board myself, how long would it take to learn this? Are there good resources? To learn it yourself, assuming no prior experience or knowledge, would take years of full-time study.

We’re talking low speed data lines and run of the mill digital circuits, not 10GHz range RF amplifier design. A month is probably enough.

I assumed zero prior knowledge. I'm a pretty smart guy but I don't think I could go from zero to "designing an esp8266-compatible board that includes an e-ink display" in a month.

Re: We made an open source ESP8266 dev board for makers

#127

Post by tripletao »

R0b0t1 wrote: post #124
tripletao wrote: post #63

Earlier quoted context omitted.

> Test and measurement supersedes intentional emission. On what authority are you claiming this? The language LeifCarrotson quoted refers only to digital devices, and the language I quoted above says plainly that a digital device must be an unintentional radiator. To be clear, I believe selling their dev board is fine, but it's fine in the same way that driving 60 mph in a 55 zone is fine. Anyone selling an intention…

On what authority are you claiming otherwise? My opinion comes from experience and getting things certified but also common sense and observing enforcement patterns (the latter of which is most important until they overstep and get challenged). Go back to my example: Does a one-off product need to be certified to be transferred to the people that paid for it? Keep in mind, best case, this will add a roughly >$10k fix…

I am claiming this on the authority of the text of the regulations. The USA is a nation of laws, and those regulations have the power of law. If it came to that, a judge isn't going to disregard them just because you think they're too expensive. If you think otherwise, can you provide case law to support your view?

By law, that one-off intentional radiator absolutely does need to be certified. The FCC's enforcement priorities will be different depending whether that product is a little 2.4 GHz radio or a television transmitter, but their enforcement discretion doesn't change the law. Anyone who wants to be compliant needs to pay for the testing (or use a certified module, which is often easy and cheap; I've done that several times myself).

Lots of people disregard lots of laws because they're too expensive to comply with. Most of them get away with it, and a few of them get nasty surprises. I believe that I've given both the correct legal advice and a correct description of typical (not fully legal) practice. It's not helpful to conflate the two.

Re: We made an open source ESP8266 dev board for makers

#128

Post by gramsejr »

jhallenworld wrote: post #4

Is the antenna open source? Is it characterized (bandwidth, efficiency, radiation pattern)? Almost like one from here: https://www.ti.com/lit/an/swra351a/swra351a.pdf

Yeah the antenna footprint is actually that one provided by ti. I had created a footprint from that pdf but then I found a kicad footprint somewhere that looked a little nicer than my rudimentary skills. This was my first design with an antenna and I am certainly not a good rf engineer. I'd appreciate any tips and feed back.

Re: We made an open source ESP8266 dev board for makers

#129

Post by gramsejr »

matthewfelgate wrote: post #104

Interesting project. By why no USB? Why does it have a Relay?

What do you mean by no USB? There is a CH340C uart to USB chip onboard and a micro usb port. Is there something specific you're looking for?

The relay would just be used as a switch to turn on/off an external device using higher voltages, AC or DC.

Re: We made an open source ESP8266 dev board for makers

#130

Post by antoniuschan99 »

gspr wrote: post #90
antoniuschan99 wrote: post #58

Earlier quoted context omitted.

Esp-idf is amazing . Esp8266 doesnt have flash encryption and secure boot. Esp32-s2 does though.

> Esp-idf is amazing . I have the opposite experience. Sure, if you just need to adapt their examples a bit, it's quite smooth. But the documentation is horrendous! If you need to do anything non-trivial that isn't covered by examples, I found it very very hard to work with. The documentation barely exists and is written in poor English. Compare this to the documentation for ARM SDKs, for example! Night and day.

I was comparing the Esp-idf to the Arduino libraries! The documentation isn't too bad, it's quite lengthy. The examples, tutorials online, and github issues in the idf repo help a lot too since the documentation doesn't dive into code examples too well.
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