John,

I would be happy to review your PCB schematic and layout. What kind of material are you planning to use? Usually FR-4 is not suitable for RF ~1 GHz as impedance is not well controlled.

For future versions, there is an intermediate step between a module and a full custom ASIC (see https://www.zglue.com).

Cheers,

Rafael


Rafael J. Betancourt, IEEE Senior Member, TEMS-SCV Vice-Chair | betasoft@ieee.org | 650.224.6849

On Tue, Nov 13, 2018, 11:13 PM John Fitz <johnfitzeecs@gmail.com wrote:
Hi all,

So definitely going for ICs on board rather than modules for this next build. The cost savings are just to great:

ESP32 $2.6 per IC vs $3.7 for module = savings ~$1
LORA $3 per IC vs $9 per module = saving ~$6 x 2 = $12
CN3791 + passives ~$1  vs $3.5 per module = saving ~$2.5,

I believe as long as we don't advertise, we can sell uncompleted boards for home use without FCC Certification (per FCC Part 15.23).

Nico: I'll definitely have pinouts for a DHT22 sensor and much more.
Rafael: A schematic/board review would be a great help. I'll notify everyone when the board is ready for review. Maybe we can try and integrate everything onto an IC one day...
leez: we'll definitely have to do some power consumption/efficiency testing with new boards. Maybe we can integrate power monitoring with the lora mesh.

The new board is located in the repo here ( https://github.com/sudomesh/disaster-radio/tree/master/hardware/board_v4 ),  please let me know if anyone has issues opening the board in KiCAD,

-Fitz


On Tue, Nov 13, 2018 at 11:53 AM Morgan Allen <morganrallen@gmail.com> wrote:
Awesome! Glad to hear about the switch to ESP32.
I've already been putting in a lot of work developing an SX127x driver for this chip.
Feel free to bug me for any direct support if that gets used (or even arduino-LoRa, I'm a co-maintainer on that)

Going to attempt to swing by tonight.

On Mon, Nov 12, 2018 at 8:34 PM John Fitz <johnfitzeecs@gmail.com> wrote:
Hi all,

I finally have some free time to work on the next Disaster-Radio dev board. Before I get started, I wanted to double check the major components with everyone:

* ESP32
* 2x LORA IC
* SD FLASH CARD
* CN3791 MPPT solar charger
* 18650 LiPo Battery

I'm considering ditching modules for this next build and using IC's directly on board for the ESP32 and Lora IC:

This will definitely lower costs and allow a bit more flexibility. I'm not sure if the RFM95 is available directly as an IC. Is there any issue with using the SX1273 instead?

I'll be at hardware hacking tomorrow night too, if anyone has any ideas or wants to brain storm.

-Fitz
_______________________________________________
DisasterRadio mailing list
DisasterRadio@lists.sudoroom.org
https://sudoroom.org/lists/listinfo/disasterradio
_______________________________________________
DisasterRadio mailing list
DisasterRadio@lists.sudoroom.org
https://sudoroom.org/lists/listinfo/disasterradio