Fingers-crossed that @geeksville gets the new board on Thursday.
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I’m very interested in a 1 watt Meshtastic device. When you get to something releasable (even order your own parts/hand assemble) I’d love to help out and design a 3D printable case for it.
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@dafeman great idea, I had roughly the same design in my head. Mainly to use the new lora 1262. My experience with E22 suggests you need to pay extra attention to antenna design if you want to see the extra gain [check you antenna with a VNA at least].
@geeksville appreciate that you are giving users freedom of choice for the hardware, that indeed will encourage many more ideas to come in!
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Really cool project!!
I designed a board with similar requirements several weeks ago, long before I knew about the meshtastic project.
In the next version I would probably leave out the complicated power latching circuit because I had problems with it and try out a sunlight-readable LCD…
Haven’t been able to test the 1W Version because the nrf52840 modules are stuck in transit for Tages…
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Awesome, really nice looking boards! What issues did you have with the power latching circuit? I’m looking at using the STM660x which looks rather trivial.
I have the E22 900M30S talking with Meshtastic however I need to figure out the best way to handle the RXenable pin.
Yeah I also have some of those STM660x in some drawer.
Due to a lack of time I was not able to solve the latching issue. I have the adafruit feather nrf52840 bootloader installed on the board. Maybe It was some GPIO init issue. Now wondering whether the chip got damaged in the process because I can only use one button at a time and the device freezes as soon as I initialize the i2c fuel gauge which works if you flash the sparkfun test sketch only.
Maybe we should just stick with a plain old slide switch. Other than that the SX1262 and display work well in this configuration (RadioLib library).
Does RadioLib handle the RXenable pin of the E22? I know it can configure DIO2 to control TXenable using lora.setDio2AsRfSwitch(true). But nothing about the RXenable.
No idea, sorry, I’m so early in my testing stage that I only controlled the pins manually
No worries, shouldn’t be too hard to get Meshtastic running on it.
Is anyone willing to add support for this board?
What features would you like to see in the next revision?
So far we have:
-small and power-efficient 128×64 transflective LCD
-proper on off switch
-GPS connector with Vcc GND TX RX and a high side power switch to save power
-some GPIO for extensions
-qspi Flash?
-3d printed enclosure
I think this nrf52840 SX1262 combo is the way to go
I would happily add support for that board 
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Thank you! Glad you like it.
Which core are you planning to use? The Adafruit core? It is stable enough and draws about one mA in normal RTOS operation and BT connected (assuming you use delay()), which is absurdly low. I wrote a smartwatch firmare around it and was pleased because it has a ton of functionality. For example their BT central implementation is really interesting and useful
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Both Versions assembled and confirmed working. Surprisingly both draw about 50mA in RX mode without any optimizations. I expected the smaller one to draw less. An arduino test sketch that demonstrates the most important functions is in the github repo. The 30dbm module is a beast, but the power supply configuration can handle the current spikes.
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yep - I’m using the adafruit nrf52 arduino core. I would happily port meshtastic to run on your awesome board.
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Cool, really looking forward to that! Let me know if you need more info. I’ll try to assemble more boards and to further debug and improve. Everything will remain open sause so anyone with SMT skills can make their own.
Ordered some T-beams too to become tester of the current functionality …
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I’d be interested to assemble. I have some experience with 0603, but also can use a relatively inexpensive assembly shop in Eastern Europe (Ukraine) Do you have BoM and gerbers?
I’m looking to make US version for 915MHz
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Assembled one more of those smaller boards after receiving fresh nrf52840 modules (which came with a metal RF shielding can) and it does work! It draws 9mA with BT permanently connected/advertising and with the radio in txco receive mode (backlight off).
The nrf52 on my first build was actually partially fried during initial testing. What a frustrating experience this can be.
Whatever. Version 1.1 of both boards is in the making. I think I’ll stick with the small IPS screen for now. It’s just too cute. Own a couple of ST7565 and UC1701X LCDs with 128x64 but I think they’re too large. Maybe the 1.4’’ one might be OK, but not now…
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btw - I haven’t yet coded the meshtastic proto to bluetooth adapter for NRF52 (because no one besides me had NRF52 based boards). I guess I better get on that quick
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Hey Dafeman,
The E22M-module has 2 pins to control the antenna switch: RXEN and TXEN. In receiving mode RXEN is set HIGH and TXEN is set to LOW. In transmit mode RXEN is set LOW and TXEN is set HIGH. You need to call the functions enableRX() and enableTX() before you start receiving or transmitting.
Maybe this
eByte E22 modules use DIO3 to enable/disable the chip’s oscillator.
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