I ordered PCBs from JLCPCB and components from LCSC. I think each one cost around $5 in parts, and I hand-assemble them as I need more around the house.
https://github.com/sowbug/smart-usb-switch
Picture: https://raw.githubusercontent.com/sowbug/smart-usb-switch/ma...
I used ws2812b leds, wemos d1, and a level translator since the d1 has 3.3v gpios but ws2812b technically requires a 5v signal.
I have two rows of 32 lights, so a beefy supply was needed along with a few places where VIN was fed to the strip.
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.
How certain are you the fish can't see the PWM?
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 good resources?
If I were to pay somebody to do design this, what order of magnitude would the cost be in?
> https://eckstein-shop.de/Waveshare-Universal-e-Paper-Raw-Pan...
I really recommend it, designing PCBs is very enjoyable (at least to me).
Then you can order your PCB at a local shop, manufacture it yourself (with toner transfer, a CNC at a hackerspace, etc) provided the traces aren't too thin and there are not too many layers (1 is easy, 2 is standard and cheap, more layers are expensive), or order it from china at a relatively low price (jlpcb or seedstudio will average something like $1/apiece).
PS: And yes, while I really suck at soldering, working with physical products feels like a nice counter weight to the software world.
To learn it yourself, assuming no prior experience or knowledge, would take years of full-time study.
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 supports JTAG debugging, which can be quite handy.
I recommend you to check that out.
A few questions:
* Should the relay have some sort of isolation, like an optocoupler?
* Is it FCC-certified?
* Like other people asked, any information on how the antenna was designed?
I like the old-school dome LEDs. And it's cool to see another project with a CH340 USB/USART bridge, even if they wouldn't need it with an ESP32-S2.
https://omronfs.omron.com/en_US/ecb/products/pdf/en-g5le.pdf
Though it does look like the clearance/creepage distances on the PCB to the low-voltage ground plane are not any wider than 2mm or so, which is acceptable for 120VAC, but not acceptable for 240VAC per IPC9592.
I wouldn't worry about sticking this in an enclosure and using it to turn a light on and off, but I wouldn't want to be handling it while it was live, either!
Regarding FCC/UL certification, a product is exempt from FCC certification requirements if it's "A digital device used exclusively as industrial, commercial, or medical test equipment", which most development boards are. I've got some dev boards from Microchip on my bench right now which aren't FCC or UL listed, either.
> (k) Digital device. (Previously defined as a computing device). An unintentional radiator (device or system) that generates and uses timing signals or pulses at a rate in excess of 9,000 pulses (cycles) per second and uses digital techniques; ...
https://www.govinfo.gov/content/pkg/CFR-2009-title47-vol1/pd...
This has Wi-Fi, so it's an intentional radiator, so it's not a digital device. I believe this product would be technically noncompliant if not certified, though lots of stuff like this gets sold and I've never heard of any enforcement action.
Their best counterargument would be that it's a component and not a self-contained product. That seems true for many dev boards but not particularly true for this one. Since the practical risk of interference is extremely low, I'd guess the FCC is happy to leave this grey for now.
If you have never sought certification know that it is quite expensive.
What seems to matter the most is if anyone actually notices interference, and if they do how widely the device ended up being sold. If a test and measure product starts making it into everybody's house eyebrows will be raised.
If you misuse a test and measurement device and generate interference it is typically on you.
It would certainly appear to lack the FCC ID label/marking it is required to have if it is FCC certified. So probably not. Thus, it also appears doubtful whether it can legally be marketed or sold in the U.S.
"Based on the definition above, it looks clear that non-authorized kits that are intended to form a complete product when fully constructed are technically not legally permitted to be sold in the US. That is because if you are marketing and selling a kit to an end user, which the user will then build into a full product, there is no reason to suspect that the normal rules would not apply."
The subassembly rules could work, if they apply, but I don't see how this product fits the definition of a sub-assembly:
"No authorization is required for a peripheral device or a subassembly that is sold to an equipment manufacturer for further fabrication."
In fact, I think it's a stretch to say that any of these test-kit, dev equipment, or subassembly rules apply. This basically strikes me as being marketed as a consumer product -- albeit a product for very tech savvy consumers.
In addition, this product lacks a CE mark and has no UL/FM/CSA listing. I'm curious what creepage/clearance requirements were factor into the design. This product is potentially dangerous if the relay is switching line voltage.
I got 3 units built for myself by PCBWay at a cost of $77. I got quotes of ~$500 for 100 units from Elecrow and Makerfabs, but didn't know what to do with the other 90.
Although I really want this great little gadget to be easily available, I can't afford $10,000 for FCC certification, and therefore I have no solution.
If anybody wants more details, email espusb@gmail.com and we can chat about it on there.
That's not how it work. You start by selling them, prove the concept, and when you have the money, you sort out certifications & whatsnot.
You won't become a unicorn if you think about doing everything _by_the_book_ from day one.
If it doesn't have a shield, it's almost certainly not FCC certified.
If it does, it's more likely to be certified.
I convinced my boss to let me sell these as open source since we found many cool IOT uses for them around the office as well, that's why you are getting the RS232 on there but most people probably will not need that feature, but hey... it is there if you need it :)
Esp8266 doesnt have flash encryption and secure boot. Esp32-s2 does though.
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.
esp-idf worked on the first try.
rs232 can run quite long distances.
https://www.amazon.com/dp/B08GY2GTW5?ref=myi_title_dp
I'm curious about availability. Are they ready to ship? Awaiting preorders?
EDIT: Oh I see 18 in stock. Probably remains of a small run to gauge interest. I hope it takes off. I'm going to make it 17. :-)
Are you planning to sell a case to go with it?
Almost like one from here: https://www.ti.com/lit/an/swra351a/swra351a.pdf
Also I wish it was available in Canada.
But you can also do so much more: these chips have lots of GPIO pins so you could control anything that an Arduino or another microcontroller can control such as relays, displays, temperature/humidity/proximity/etc. sensors, LED strips, motors, heaters, and so on. But the kicker is that with built in WiFi so you can natively get it online. A lot of smart lights now have these chips in them for example and you could make your own. Or your own internet connected green house with vents you can open/close and sensor readings for temperature and humidity in the air and the soil. Or an RC car you control from your phone. Or shades that open and close based on time of day. Or a garage door opener. Basically if you need a gadget you control over a network, these probably should be your first potential solution. They are low power and physically small compared to something like Raspberry Pi’s or other single board computers and more powerful than Arduinos.
I've mostly been looking at the ESP32, though (newer, also has bluetooth and 2 cores, and is lower power), and some of the ARM Cortex-M-based microcontrollers.
As the device has onboard WiFi I can poll a remote site to get data and display it, updating every few minutes. I use that to show the next departure-times at the tram-stop round the corner from my house.
Sure I could use an app, or even walk there and wait, but it's nice to know when to leave - especially in winter-time!
Alexa enabled switch to turn on / off a TV using the IR blaster
my boss used 3 of these this to build a smart sprinkler system for his house.
[1] https://docs.platformio.org/en/latest/what-is-platformio.htm...
Ethernet: https://github.com/cnlohr/espthernet
PAL TV: https://hackaday.com/2016/03/01/color-tv-broadcasts-are-esp8...
I haven't yet seen an FM transmitter though, but it's been done on the Raspberry Pi GPIO so I guess it could be done on the ESP also.
It makes me wonder if there’s interest in more of these type ofESP* dev kit boards. One I haven’t seen is one with just Ethernet PHY but no Ethernet jack/magnetics. It’s been useful in my designs to have a ETH+/- that can be brought out to various Ethernet / PoE setups. Something like the wESP32 is handy for kits but not for integration.
I have hacked something on a protoboard for nodemcus before, but it ended up being pretty messy.
$19.99 seems a bit expensive to me though.
Is there any intention to add WiFi support to the dev kit?
The relay would just be used as a switch to turn on/off an external device using higher voltages, AC or DC.
What is an "ESP8266 board"? Is that something that is so common it doesn't need explaining? Of course I will google it [and probably buy one], but just pointing out that it's not very clear from the website!
[EDIT: ok, after 10 minutes of googlin', it seems no one will explain what it is - it's just "an esp8266 system on a chip". It must be the first rule of ESP8266 club...]
It's a bit harder to get started with than your average arduino project. If you want, you can use the Arduino IDE which hides a lot of the complexities. But the docs from espressif are aimed more at the firmware engineer crowd, so if you want to get serious there's more of a learning curve (IE nvflash partitions, understanding what a bootloader is, etc). Also, you'll probably end up getting into freertos at some point, which further complicates things. But it's a super great module for home projects.
The esp-32 is a newer chip which is similar but adds bluetooth. In general you're better off going with esp-32 nowadays -- it's got a second core as well.
Until recently the only thing missing was USB (though there were bit-banged USB implementations!). But now there's an esp-32 with USB too, so really for the cost, the features are unparalleled.
If you're okay with things not being as polished as the Arduino experience (you might have to learn "real" firmware programming), it's really the best starting choice for your side projects.
The older board didn't have integrated USB, which made the dev process annoying.
It's a basic 32bit RISC microcontroller, generally running at 80MHz, with built-in WiFi support. They're often available as modules with either a pin header or castelated edges for surface mounting.
They are supported on the Arduino platform and Platformio.org, as well as some other platforms. They've become quite popular due to their low cost (often available for under $10 at individual quantities) and the fact that they include wifi.
