We recently released our ESP32-S2-DevKit-Lipo development board with ESP32-S2 SOC. It has the same functionality and pinout as Espressif ESP32-S2-Saola-1, but in addition it has a LiPo charger and battery management and is designed for Ultra low power – only 30uA consumption when on battery and deep sleep. This allows handheld battery operated applications. The LiPo part can power external sensors/circuits. This board has a built-in programmer with a CH340T USB-Serial convertor.
Many have noticed that ESP32-S2 has a native USB-OTG. Then why did we put the CH340T on it? The reason is that the Espressif SDK didn’t support USB back when we designed this board.
Now Espressif SDK adds support for a USB bootloader and the programming of the ESP32-S2 can be done by the native USB interface, we decided to make a new revision where the native USB-OTG interface is used.
We wanted to keep the LiPo battery functionality and this created an interesting technical challenge: the USB-OTG port can be used both as device and host. When used as a device, the board is powered by the USB and LiPo battery is charging. When used as a USB host (i.e. you can attach USB devices to the port) the USB port must supply 5V to the USB devices connected. Our first prototype had a power supply problem: when the ESP32-S2 works as a host the battery is powering the USB-OTG port with 5V, but there is attached also the LiPo charger circuit, so infinite loop is made: battery -> step up to 5V -> USB -> LiPo chgarger -> battery 🙂
This issue was preventing us from releasing this board earlier, but now on Rev.B all of these issues are fixed so we are about to run production.
Needless to say we kept the ultra low power design and the new board also consumes as low as 30uA in deep sleep.
Searching on the net it seems that no one else has implemented a USB-OTG functionality to the ESP32-S2 yet so this one will be the first. Also to the best of our knowledge there is still no software support for a USB host on the ESP32-S2 but we hope after our hardware is released this will push and accelerate the software development further.
ESP32-S2-DevKit-LiPo-USB is going to be released as Open Source Hardware like other IoT solutions we have.
ESP32-S2 is new SOC from Espressif which fills the gap between ESP32 and ESP8266.
It has the same memory model as ESP32 but has cut the Ethernet and Bluetooth parts, so only WiFi connection is possible – same as ESP8266, but offers more power, secure boot and encrypted firmware. Also support of decent SSL connection, something which lacks in ESP8266.
Pricewise now S2 is a bit lower cost than ESP32 and more expensive than ESP8266, but there is very strong competition in this niche coming from the new Bouffalo BL6XX chips, so my prediction is that to stay ahead Espressif will further lower the prices of ESP32-S2 to match ESP8266 very soon.
For comparison with ESP32 and ESP8266 the new ESP32-S2 has plenty of GPIOs up to 43!
Initially Espressif has announced that their ESP32-S2-WROVER modules will have as low as 2-4uA consumption, but later they increased this value to 20uA. Not quite well as their target but still very good achievement.
To keep compatibility with SAOLA-1 we add RGB LED, but also add LiPo battery charger and ESP32-S2-DevKit-Lipo can operate even without external power supply only on LiPo battery, there is battery level monitoring and external power supply sense. ESP32-S2-DevKit-Lipo can power external circuits with 3.3V up to 200mA when operate on battery.
ESP32-S2-DevKit-Lipo has build in programmer with CH340T. There is possibility the programmer part to be excluded and to use ESP32-S2 directy USB connection.
When operating on battery if the RGB LED is enabled the power consumption is ridiculous 700uA as the RGB LED appear to use lot of current even when not in operation, but there is RGB disable solder jumper which if opened you will not be able to operate the RGB LED on battery but will decrease the power consumption to total less 30uA in deep sleep.
Sometimes devices connected to USB ports need to be re-set. It’s not unusual GSM modems and WiFi dongles to freeze and the only way to bring them back to life is to remove and re-attach.
OLinuXino USB ports has power switches and current limiters which can be controller by Linux drivers.
After some experimenting we found that it’s not so easy actually to do it with the standard file system and shell.
A friend suggested to try this code. It worked very well, so here is how to use it. First you need to download and compile it, then to make it executable:
$ mkdir usbreset
$ cd usbreset
$ wget $ https://raw.githubusercontent.com/jkulesza/usbreset/master/usbreset.c
$ cc usbreset.c -o usbreset
$ chmod +x usbreset
Then you need to see where your USB device is. In our case I connected MOD-WIFI-R5370 WiFi USB dongle:
$ lsusb
you will see something like:
Bus 002 Device 039: ID 148f:5370 Ralink Technology, Corp. RT5370 Wireless Adapter
to reset this device use the command:
./usbreset /dev/bus/usb/002/039
The device USB port will be power off for a second then power on again.
All above is tested and work with official Olimex Linux images from images.olimex.com, but should work on other Linux distributions too.
Our popular ESP32-DevKit-Lipo, ESP32-POE and ESP32-POE-ISO now has option with external antenna, so you can use them even with metal boxes. The external antenna extends their range by 20-30%.
We stock now ESP32 modules with 16MB of Flash, so if you run out of memory you can order any of our ESP32 boards with 16MB Flash module too.
Also we have ESP32 modules in extended temperature range -HT (high temperature) which works from -40C up to 105C for demanding applications.
We got these as we have cool idea for WiFi OBD2 sequencer which will allow you to send pre-programmed OBD2 sequences to your card OBD bus allowing to do amazing effects with your car lights close doors with your phone and etc.
IR-BARRIER-100M is infrared fence for perimeter protection. It comes with dual beams and adjustable sensitivity.
SNS-TMP-DS18B20 is digital temperature sensor which works with Arduino libraries and allow easy to make Solar Water Heater controller with ESP32-EVBÂ and MOD-LCD2.8RTPÂ . Two sensor can be addressed via single wire.
GLASS-TAPE20MM is glass re-enforced tape which is very strong and heat resistant.
Water proof push buttons with three sizes 12mm, 16mm, 19mm and four colors LED rings: Red, Green, Blue, Yellow, White:
ESP32-WROOM-32D-4MB – this is equal to used by us ESP32-WROOM-32, it uses D0WD instead of D0WDQ6 which is with smaller size and Espressif recommend it for new designs.
ESP32-WROOM-32D-16MBÂ has 16MB of Flash
ESP32-WROOM-32D-4MBHT is High temperature +105C module for demanding applications.
ESP32-WROOM-32U-4MB is with U.FL connector for external antenna
ESP32-WROOM-32U-16MB has 16MB of Flash
ESP32-WROOM-32U-4MBHT is High temperature +105C module for demanding applications.
ESP32-WROVER-4MB has 4MB Flash and 8MB of PSRAM.
The high temperature modules are still not in stock as Espressif manufacture these now, but all others are in stock.
ESP32-POE board is now in stock. The prices start from EUR 14.36 for 50 pcs order.
This board offers Open Source Hardware / FOSS solution and building block for distributed sensor network with power over existing LAN infrastructure.
Possible use cases are Home automation, Industrial machine logging, remote environmental monitoring, access control, remote displays etc.
The board contains ESP32-WROOM-32 module with WiFi/BLE and Ethernet connectivity , RESET and USER buttons, micro SD card, LiPo battery charger and LiPo connector which allow board to work even with power supply drops.
The UEXT connector on the board can be used to connect many different sensors like:
Si3402-B chipset takes care for the power over ethernet, it’s IEEE 802.3 compliant, including pre-standard (legacy).
Important notice, to keep board compact and as it’s main purpose is to connect to cloud different remote sensors there is no galvanic isolation between board and the power delivered by the LAN switch or router.
ESP32-POE has internal programming interface and you can program it with Espressif SDK or Arduino via USB cable. As the board is not galvanic isolated from the Ethernet power supply, before you connect the USB cable to your computer you should remove the Ethernet cable or you should use USB-ISO between your computer the ESP32-POE!
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