| Electronics > Projects, Designs, and Technical Stuff |
| 'Dreamer1' - LoRAwan Module based on Microchip SAMR34 |
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| georges80:
Nice project. I went the easier route and made a board that you can solder one of the RFM style modules onto. Used an STM32 64k flash part. Added a buck/boost to run off a lifepo4 and added a PWM charger for a cheap solar panel to charge the lifepo4 battery. Some basic voltage sensing and I can PWM charge the battery up. Brought out a bunch of spare gpio pins for 'come in handy' projects. Also a header for connecting one of the cheap SD card logger modules directly to the UART pins. If not logger then I can just connect the UART pins to a GPS module for instance. (Heavily) modified radiohead code for allowing units to talk to each other since I'm not after lorawan/iot usage but more standalone data comms. Anyhow, pic of board below. I think lora is quite an impressive technology for the price point. Basic test (I have many more I need to do) was 1.5km across an open field and still getting better than -80dbm rssi being reported from the sx1276 chip using low gain antenna on each end just hand held. I think my BOM is <$10 for the board (10 piece component order) and it's about $5 for the RFM module from one of the many asian vendors. Simple 2 layer board from jcpcb. cheers, george. |
| mrpackethead:
--- Quote from: kentfielddude on February 12, 2019, 06:43:57 am ---Can you post the gerbers please? --- End quote --- I have pushed them to the git repo now. If you are going to build a board from it, you'll need to make sure it matches the board stackup as well. Please note that this is as still untested. |
| mrpackethead:
--- Quote from: nano on February 12, 2019, 09:06:11 am ---Maybe it’s just the schematic symbol that’s misleading.. For me it looks like the switches RESET and SW0 are shorted to GND. I haven’t checked the PCB though. --- End quote --- Thanks for this. I've updated the schematic and actually replaced the switches with somethign thats better placed. Now in the repo. |
| mrpackethead:
--- Quote from: georges80 on February 12, 2019, 05:07:13 pm ---Nice project. I went the easier route and made a board that you can solder one of the RFM style modules onto. --- End quote --- When you are adding a RF section to another board that is quite a useful idea. Something you do need to watch however is when your RF comes off the module to your antenna. Your trace looks like it will be pretty poorly matched ( impedance wise ). At the short distance it is, it may not be an issue. but it coudl be impacting your overall output. The SAMR34 is both a micro and the radio in the same chip. My use case is a little differnet from yours, i was wanting a way to quickly add sensors on breadboard or just wired on, without the need for another PCB. I doubt I would ever use this as part of a real product ( unless it was a one or two off ). >Used an STM32 64k flash part. Added a buck/boost to run off a lifepo4 and added a PWM charger for a cheap solar panel to charge the lifepo4 battery. Some basic voltage >sensing and I can PWM charge the battery up. Brought out a bunch of spare gpio pins for 'come in handy' projects. Also a header for connecting one of the cheap SD card logger >modules directly to the UART pins. If not logger then I can just connect the UART pins to a GPS module for instance. Yeah, you've designed something for a specific usecase. I like doign that, and getting everythign on a single board, with no wires/connectors! >I think lora is quite an impressive technology for the price point. Basic test (I have many more I need to do) was 1.5km across an open field and still getting better than -80dbm >rssi being reported from the sx1276 chip using low gain antenna on each end just hand held. For point to point, lora is great, and you get to make it run faster, and dot' ahve all the MAC overhead. When you have 200 sensors ( and they only need to send a few bytes a day ) LoRaWAN is kind of appropriate. Theres no reason why this board couldnt do the same thing. .You coudl build a 500kbit point to point Serial link with it. >I think my BOM is <$10 for the board (10 piece component order) and it's about $5 for the RFM module from one of the many asian vendors. Simple 2 layer board from jcpcb. Yes, i am always quite amazed at what you get for your money now! [/quote] |
| mrpackethead:
Some updates; since i did'tn quite send it to fab, before i changed my mind. :-) Modifyed buttons, added a AT608 Crypto IC, and a Bosch Air quality sensor on the I2C bus. |
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