Bulgarian Open Source Hardware Smoke and Movement IoT sensor project on Kickstarter


The Bulgarian Kickstarter projects are rare, this is why it was pleasure to see one there and on top it’s Open Source Hardware and Software project!

The project is announced as Open Source, but the sources are not published yet, although from the description they work on it since 2016, which I reported to the team as mistake.

Not releasing the sources from the start of OSHW project deprives the team from valuable feed back and tips from potential collaborators, but as far I understand this is their first such project, so let’s wish them luck!

Amazon FreeRTOS IoT ported on STM32-E407 board


Amazon announced few weeks ago about their AWS stack support for FreeRTOS. As their development kit is not yet shipping, Roedan Embedded Systems decided to fork their GitHub repo and port to available boards like STM32-E407.

via Twitter

ESP32-PRO new IoT board with 4MB external RAM, 4MB external Flash, external crypto engine, LiPo charger


What you see above is our attempt to make ESP32 board with 4MB RAM. Reading the ESP32 datasheet this is quoted as the maximum possible external RAM possible to attach.

It’s named ESP32-PRO and here is the Github repo for it.

We encounter lot of problems while designed it, thanks to Rudi from ESP32.de for the tips and help. As there is the usual mess with the documentation and lot of unclear stuff.

We saw in the new WROVER-KITS we got that the module which is used is not WROOM, but WROVER and inside it has pSRAM.

The pSRAM is working on 1.8V and share same data pins as the Flash so we had to find 1.8V Flash also.

Another issue is that in the documentation pSRAM clock and data are reversed for unknown reason, but at least the software which run on WROVER module has these correctly set 🙂 so we had to ignore the Espressif datasheet and user manual info.

On top of this in the documents never mention that GPIO12/MTDI must be pull high if the power supply is 1.8V neither their reference design show this.

At least now having OSHW board with all correct settings will help other to not struggle all obstacle like us on the road to add external RAM.

We had to go to bare ESP32 chip as the RAM signals are not available on WROOM neither WROVER modules, this will lead to paid certification which we still do not know how much will be, but will have to add to the sale price of this module, so price is yet unknown but will be fair 🙂

As Rev.0 of the ESP32 chip has issue with cache for external RAM, we try to communicate with Espressif if we have to expect other bugs and issues with Rev.1 using external pSRAM, will keep you updated.

Beside the ESP32 we add PIC32MX270F256DT, this is nice processor with USB-OTG which will allow ESP32 to connect to both USB hosts and to act as USB-host and read for instance external USB Flash or take pictures from USB Webcam etc.

Why not AVR? Because AVRs are in trap of their own success. For the price of PIC32MX270F256DT which has 64K RAM, 256K Flash and USB-OTG you can buy ATMega32u4 which has only 2K RAM and 32K Flash and just USB device.

PIC32MX270F256 opens much more possibility with plenty of Flash and RAM.


Sneak preview of new OSHW IoT board: ESP32-Gateway


ESP32-EVB really took us lot of time to complete mostly due to the not so complete documentation around Ethernet and our own silly errors. Also we wanted to add so many interfaces there to may people evaluate them all: Ethernet, CAN, Infrared, Relays LiPo UPS etc etc and the board become 75×75 mm. The price also went from EUR 22 to EUR 26.

In parallel we quietly were working on stripped version named ESP32-GATEWAY, as the name says we wanted just to keep here the connectivity: WiFi, BLE, Ethernet, USB for programming and micro SD card.

All available GPIOs are made on 0.1″ step strip at the bottom of the board, and two nice mount holes:


Today we assembled the first prototypes and we will test tomorrow. If everything is OK we will run production. We already have 100 blank PCBs ready as after so much time spent on ESP32-EVB we do not expect any troubles, but still wanted to reduce the risk to throw in the garbage bin more than 100 boards if we missed something.

So hold your breath if everything is OK we will have 100 boards for sale next week 🙂

The price of ESP32-Gateway will be EUR 22.

ESP32-WROVER-KIT is back in stock


The popular ESP32-WROVER-KIT is back in stock!


EDIT: The new batch has ESP32-WROVER module on it:


Instead of CH340 USB to Serial now it have FT2232HL wich implements two Serial channels one for programming one for debugging.

Also as these were assembled end of May they contain WROVER modules with 4MB of RAM and ESP32 chip REV.1.



ESP32-EVB now get much better

ESP32-EVBESP32-EVB revision A was made quick and has too many errors 🙂 some were due to the non very clear documentation, like that we assumed that all ports could have internal pull-ups but  when we try to write the software we found that the GPIOs we used for the buttons has no such. Other were done by our engineer negligence.

We had small 100 pcs series from Revision A, but after all issues we encounter just decided to trash it and just move forward to revision B.

Now in Revision B all interfaces are tested and confirmed to work fine 🙂

What we keep:

  1. Two relays 250VAC/10A
  2. LiPo charger which allow ESP32 to work without external power supply
  3. Reset and User button
  4. micro SD card
  5. UEXT connector to add temperature, humidity, etc sensors
  6. GPIO with all signals available on 0.1″ proto friendly step connector

What we add:

  1. USB connector now is also used for automatic programming of ESP32 so no need for external serial cable, with DTR and RTS bootloader mode is entering automatically
  2. Ethernet now is correctly wired and works 🙂
  3. We were surprised to read ESP32 has CAN and we try and it works great, so in the new revision we add CAN driver
  4. We add Infrared transmitter and receiver, so now you can control all your home appliances with IR control like TVs, VCRs, Air conditioners, and everything else with IR control

What we removed:

  1. second button, with all above peripherals the ESP32-WROOM-32 module resources are gone, there is no single GPIO unused left

Revision B schematic can be reviewed here . The PCB is now routing.

Color TFT 2.8″ LCD 320×240 pixel display board with UEXT compatible to ESP32-EVB is also coming soon.

ESP32-EVB our new board for IoT first prototypes are ready


ESP32-EVB is our new board with ESP32-WROOM32 module. It has:

  • ESP32-WROOM32 module
  • two relays 10A/250VAC
  • Ethernet 100Mb interface
  • LiPo charger and step up converter allowing ESP32-EVB to run from LiPo battery
  • microSD card connector
  • two user buttons
  • UEXT connector to attach different sensors and modules
  • 40 pin GPIO 0.1″ step connector with all resources of ESP32
  • 5V power jack
  • three mount holes

Now time to write some examples and if everything works to launch production.

The sale price will be EUR 22.00

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