NodeMCU ESP32-C3 WiFi and BLE IoT boards show up for about $4

From the datasheet, it looks like the C3 doesn&#x27;t have the Ultra Low Power (ULP) co-processor. This co-processor was there on previous ESP32s and allowed you to run code for sensor monitoring or other basic tasks while the main CPU was stopped, consuming ~150µA. It can then wake the main CPU if certain conditions were met. Wonder why it was removed, and if this would prevent the C3 from being used in these kinds of low-power applications.<p>Datasheet: <a href="https:&#x2F;&#x2F;www.espressif.com&#x2F;sites&#x2F;default&#x2F;files&#x2F;documentation&#x2F;esp32-c3_datasheet_en.pdf" rel="nofollow">https:&#x2F;&#x2F;www.espressif.com&#x2F;sites&#x2F;default&#x2F;files&#x2F;documentation&#x2F;...</a>

I’ve been using a preproduction version of this (they were distributed widely on social media) with good results. It’s another iteration of the ESP32 products, but it’s not necessarily better than the previous boards for every application. All of the ESP parts have significant differences that can make them more or less appropriate for certain application needs, so read the specs carefully rather than skipping straight to picking the latest part.<p>My biggest wishlist item for Espressif would be to make a solid WiFi&#x2F;BT part with SDIO interface that can be used as a radio for a Linux host SoC. Espressif provides a hosted version of the firmware for previous ESP boards ( <a href="https:&#x2F;&#x2F;github.com&#x2F;espressif&#x2F;esp-hosted#12-supported-esp-boards" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;espressif&#x2F;esp-hosted#12-supported-esp-boa...</a> ) but it doesn’t integrate as cleanly as standard SDIO WiFi parts and their latest boards don’t support SDIO.<p>There are many cheap WiFi&#x2F;BT SDIO modules on the market, but I’d like to have one go-to solution that is known to work well, readily available, and cheap like the ESP parts are as wireless micros.

I assumed with the shortages that these went up in price. Or more specifically the link I previously used to buy node d1 mini has gone from $3 to $8. Guess I should have looked harder.<p>I might pull the trigger and buy 10 of these for all sorts of purposes.<p>On a side note, these made a bad taste in my mouth for Arduino. It&#x27;s making me think all Brand names should be a red flag.

RISC-V for $4.30 USD? Sounds like they&#x27;d sell like hotcakes...<p>NodeMCU ESP32-C3S_KIt<p>Specifications: Wireless module – AI Thinker ESP32-C3S (footprint compatible with ESP32-S &#x2F; ESP32-WROOM-32D) with ESP32-C3 RISC-V processor @ 160 MHz, 2.4 GHz WiFi, Bluetooth 5.0 LE, 4MB flash, on-board PCB antenna, and IPEX connector (which may be soldered or not). USB – Micro USB port for power and programming via CH340C USB to TTL chip Expansion – 2x 15-pin headers with GPIO, SPI, UART, ADC, I2S, 3.3V, GND Misc – RGB LED, Reset key, user-programmable key Dimensions – 49 x 26 mm

More importantly, ESP32-C3-WROOM-02-H4 module is $2 at mouser.com

Huh, I wonder why these have the same old CHG USB-Serial chip on them. The C3 has a built-in serial (and JTAG) USB interface. Maybe the software support isn&#x27;t there yet?

The datasheet suggests these chips support 802.11n, HT40, MCS7, which maps to 150 Mbits of data throughput.<p>But with these little embedded systems, I know the software stack typically heavily limits throughput. Can anyone comment on real world data rates this can achieve?

My dad buys loads of this stuff from eBay and Aliexpress, we got a lot of plastic boxes just filled with modules like this. It&#x27;s a shame I don&#x27;t have any ideas on what to do with them though, they just sit there doing nothing.

Awesome. I wonder if, in future, ESP8266 chips will be replaced with this one since former is WiFi only.<p>There really needs to exist an alternative WiFi chip from another manufacturer. It would significantly drive the price down due to competition. Currently there&#x27;s no competition to Espressif in this segment. Maybe Raspberry Pi should come up with RP2040 WiFi chip. That would be amazing.<p>While we are on this topic I did a lockdown project based on ESP8266 thought I had share :p<p><a href="https:&#x2F;&#x2F;www.ankshilp.com&#x2F;monitoring_solar_panel_output_over_wifi&#x2F;" rel="nofollow">https:&#x2F;&#x2F;www.ankshilp.com&#x2F;monitoring_solar_panel_output_over_...</a>

I wonder if these would be a good fit for the DIY mechanical keyboard scene. With a board like this it looks like all you&#x27;d need electronics-wise is a battery and a charge controller.<p>I wouldn&#x27;t think it would be too difficult to get QMK running on these.<p>It doesn&#x27;t look like these are close to the Pro Micro pinout though, so perhaps a shim PCB to wire things up correctly?

I have been playing with a couple of NodeMCUs for a hobby project and I have to say the documentation and tooling are extremely poor (at least with a Mac).<p>If you&#x27;re used to the plug-and-play Arduino, be ready to spend quite a bit of time on setup before even connecting to a WIFI.

The datasheet says &quot;Out-of-band blocking performance&quot; is just -5dBm in some frequency ranges...<p>Surely that is nowhere near enough to meet the FCC requirements to still operate when faced with other unrelated radio transmissions?

Do these things have PWM suitable for power electronics applications? Meaning driving complementary pairs with dead time, center aligned, synced ADC reading, period start ISR...

ESP32(having more ram, more cores, more pins, more frequency, better than this in all the respect?) is available for $2-3 if you look for it. Why is $4 the news?

Make no mistake about it: these have been assembled using slave labour. Check out the soldering job if in doubt.

So these are for sale on AliExpress which I&#x27;ve found to be higher friction than other open marketplaces (ebay&#x2F;amazon&#x2F;etc). The last time I tried to buy something there, my checkout was interrupted by a notification asking that I submit ID and other info for screening to proceed, which I found surprising since I was buyer not a seller and was purchasing some rather mundane item, cables or jumpers, I can&#x27;t remember. In the end, the result was I didn&#x27;t complete the order because it didn&#x27;t seem worth the trouble. Additionally, I&#x27;m a little hesitant to buy some items on AliExpress because I worry they suffer from the same counterfeit issues as other open marketplaces due to poor oversight over sellers. Except for on AliExpress I have even less of a sense of how to distinguish between sellers with established reputations or otherwise. Does anyone have any tips for how to best use AliExpress?