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-EVB and MOD-LCD2.8RTP . 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-16MB 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!
Few years ago Espressif released their first low cost WiFi chip ESP8266 and turned upside down the WiFi connectivity for small MCU. They have been left relatively to no competition from the big Western chip makers who couldn’t match their aggressive pricing, but later there was semi successful competition from Realtek and now there is another competitor who is focused on low cost IoT audio applications but their chip is quite good for general purpose WiFi stuff also. The RDA5981 is based on Cortex-M4 inside
running at 160Mhz
160KB SRAM
8MB PSRAM
4MB Flash
build in USB 2.0 host interface allow USB devices to be connected to the module directly which is advantage toward Espressif chips
Support Bluetooth 2.1 EDR + BLE4.2
SDMMC interface
2x 10bit ADCs
SIDO x1, I2C x1, I2S x2, PWM x8, IR, SPI x4, UART x2, GPIO with interrupts x14
operating temperature -30+80C
According to the PR message their focus is voice recognition / audio play and they shipped already 200 Millions of these chips ин 2016. Looking at the features above they can be used for other IoT applications as well if their SDK is easy enough to use by maker community. The question is will be they smart enough to be more user friendly as ESP.
I check their web and even to download their datasheet they require registration :). I understand this as – we hide our product info from our potential customers as we do not want they to evaluate our chips. These registrations beside pissing off potential customers do not hide anything from their competitors as they would easily register with fake info and get them anyway, but obvious this is the way most Chinese companies work.
via Twitter (Thanks to Rudi!)
EDIT 10-01-2018: There is actually GitHub repo with the datsheet, so their web may be not updated!
AR9721 chipset is the only one on the market with completely open source linux drivers and firmware, this make it WiFi chipset of choice for people who respect their freedom.
We have MOD-WIFI-AR9721-ANT for quite some time and it’s very popular item, but the 200mm antenna make it not quite small. Now we add to our web shop the version without external antenna. It’s with 85 x 25 x 10 mm dimension and have same working distance as the external antenna version.
Recent Comments