Using the Teensy 3.5

This topic has 8 replies, 2 voices, and was last updated 2021-08-05 at 10:07 PM by neilh20.

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- 2021-08-03 at 1:07 PM #15779
  Rick Vogel
  Participant
  Setting up this topic at the request of @neilh to discuss advances we have made using the Teensy 3.5 board for logging data and have been able to establish remote updating, as well as, a bootloader that allows for boot from the loaded program, but checks for boot file on the uSD card first as a potential update to the program.
  
  Bootloader is taken from the uTasker project: https://www.utasker.com/kinetis/TEENSY_3.5.html
  
  Solar Charger(Dual Battery version): https://cdn.shopify.com/s/files/1/0079/6003/5417/files/ASC30W_Installation_Manual.pdf
  
  Cellular: XBee LTE-M/NB IoT
  - Used for both MQTT with TLS 1.2 and FTP-Secure for remote updating of Xbee and Teensy files
    
    Teensy files are pulled down by Xbee and transferred via serial to Teensy. Teensy writes to SD Card as received and reboots
- 2021-08-03 at 2:57 PM #15783
  neilh20
  Participant
  @vogelrnws thanks. Would you have an overall schematic of it. Sounds like Solar to +12V. Then guessing +12V battery that is the main power source. Then Teensy3.5 supply 3.5to5.5V, possibly also Xbee LTE boards
  
  https://www.pjrc.com/store/teensy35.html
  
  Probably a carrier board for the Teensy3.4 and LTE board?
- 2021-08-03 at 3:09 PM #15785
  Rick Vogel
  Participant
  @neilh,
  
  Yes, we have solar to the charger and into (2)12V 9aH batteries (in parallel). The Teensy and Xbee are on a custom motherboard we designed. Has lots of the IO broken out and spots for Adafruit GPS, RTC battery, ESP32 (older requirement) and Wiz850io Ethernet.
  
  See pic attached
  Attachments:
  IMG-9018-2-scaled.jpg
- 2021-08-03 at 3:16 PM #15787
  Rick Vogel
  Participant
  12V to 5V is a DC/DC Din Rail supply P/N: MDR-20-5. The board takes in 5V and and has a 3.3V LDO onboard for those 3.3V parts that pull more than the teensy 3.3V output can provide.
- 2021-08-03 at 5:02 PM #15789
  neilh20
  Participant
  Ahh very nice. I’m sure its worth it to get a standard design for all climates, and able to cope with keeping some sensors warm. Seems like the cost is going to go up dramatically though. Powering is a lot of cost and of course IP65 space is costly (for those batteries!!). I wonder if it is open sourced, or a private contract design. I use a 4.4AH LiIon, which is quite large for the Mayfly, and of course it can only charge at a max of 0.5A/hr – which means the solar panel is only about 3Watts (though easy to oversize to cope with shading) . Thanks for sharing and the references.
- 2021-08-03 at 6:08 PM #15790
  Rick Vogel
  Participant
  We use a polycase 12x10x6 customized enclosure for under $85 with everything predrilled https://www.polycase.com/yh-121006.
  
  We made a custom din rail bracket to hold the two batteries. 10W panel for solar but charger will accommodate up to 30W
- 2021-08-03 at 7:03 PM #15791
  neilh20
  Participant
  Thanks, good for reference – the critical aspect of any plastic outdoor box is I understand polycarbonate and those IP65 seals 🙂 Keep out the falling rain. Those ants like to get in if they can, so it is a challenge. I really appreciate the detailed guide of what to think about with https://www.envirodiy.org/mayfly-sensor-station-manual/ though I choose my polycarbonate box based on the project.
  
  When building a system, I do try and document it for myself so that I can easily repeat it, and also share it. The Mayfly can fit in a small space ~ NBB-15240 with the uSD facing outwards for easy offloading.
  Sometimes though its the instrument wires and dessicant that need routing space, so I’ve also been using the Bud PTQ-11050 and for testing PTQ-11050-C.
  
  Still it would be soo nice to have a processor with at least 4 UARTs, an embedded USB host, and a 1M flash, enough ram and timers for totalizing/counting … with a little screen for site provisioning. I’m playing around with the Wio Terminal – https://wiki.seeedstudio.com/Wio-Terminal-Getting-Started/ but how to get the sleep power usage down, and have it take an Xbee format socket with Digi LTE powering, with all the software open source license…. as ever a variety of engineering challenges. 🙂
- 2021-08-04 at 1:15 PM #15794
  Rick Vogel
  Participant
  I misspoke on the DC/DC supply. It is a Meanwell DDR-15G-5. Pic of the guts on that polycase is attached.
  Attachments:
  IMG-9355-2-scaled.jpg
- 2021-08-05 at 10:07 PM #15813
  neilh20
  Participant
  @vogelrnws nice to se the layout. That battery holder looks pretty solid and as you said 2 *12V * 9Ah gives 216WHr of capacity. a LiIon at 4.4AH @ 4V is 16Ah.
  Its great to have a discussion about the mechanical side, what works, what doesn’t work so well.
  Seems like on of the challenges is that uSD is right up against the side of the cabinet – doesn’t appear like it can be easily removed. Would require the Teensy 3.5 to be pulled first.
  I wonder also if there is any protection for static/lightening on the instrument leads. That’s a problem in certain parts of the country.
  
  The DIN rails take some thinking about. The issue as I see it is how to do assembly simple and reliably. If the screws are inserted from the front, and require a nut at the back to hold it, it can become a challenge for replacement in the field.
  
  https://www.mcmaster.com/din-rails/ shows some of the options for clips that might solve that.
  
  For the Mayfly, in the Arduino style of a low cost environment, I’ve been using a plastic polycarbonate bar, and configuring it for the mayfly holes. Here is a write up .. Bud Ptq 11050 Enclosure
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