I've been trying to get some HC-05 Bluetooth modules working to allow me to download Arduino UNOs from my PC. I have had no success and I looked at maybe 12 videos, understand the connections and the methodology. I get everything "right" but I cannot move code (download) from the IDE on my computer to an UNO connected to an HC-05. I SUSPECT an issue with Win11 and USB3 ports. Anyway...I gave up on that for now.
Meanwhile I have two UNO's connected via 433 MHz RF modules. One reads data from a temp/humid sensor (I added voltage) and sends it to the other for reading on the IDE monitor.
Gist of my issue: I have 3 projects that are outside, whose configuration I want to update WIRELESSLY, instead of going outside in the rain to make updates with a laptop and USB connection. Can I do this with this setup? (The modules are using SPI).
Hard to say, given the lack of useful information on your setup. But I will guess "no".
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Do you want to change the program or the configuration?
There’s a big difference in the strategy & methods used.
I thought it was pretty clear that I'm using RF modules to communicate and want to use them to update configuration (ie download compiled code) to a remote Arduino.
With Bluetooth, it would have been a slam dunk: look for the Bluetooth assigned port in the IDE and download. That's what I want to do with the RF. Computer to remote UNO whether through another UNO (using RF modules) or some other method.
I like the RF because it is simple and reliable.
Maybe I should just ask the big question: How can I wirelessly download an UNO from the IDE, NOT using HC-05 Bluetooth gizmos?
Another way of saying it: When I download from computer to UNO, I do so via USB. I assume this action triggers the bootloader that loads the hex/binary into the proper registers of the Atmega328 MCU. How precisely does this work and can I use serial data coming in from serial port or SPI to DO THE SAME THING? This was always "transparent" to me...it just worked and I never wondered how.
When you download via USB, you’re actually corresponding with the target via ‘serial’, USB is simply the box it’s being delivered in.
Most serial transport layers could be used to ‘download’ a new program if they’re responsive and fast enough.
If you notice when you ‘reset’ your board, the onboard Tx LED blinks a couple of times…. that’s the bootloader saying “I’m here… you have a couple of seconds, then I’ll continue with the existing program that’s already loaded”
If avrdude is running, it will see this introduction, and respond to that initial transaction with the bootloader.
A longer, more complicated process follows - to transfer blocks of the new program’s hex code across to the target, finally avrdude tells the target to reset again, and avrdude ignores the new intro’ request… the target goes on to run the newly updated code.
Thank you, this is very helpful. I had some idea on how it worked, but your comments filled all the gaps.
Have a look here , these are UNO Clones with mid modified bootloaders and RF boards that may allow remote loading ( certainly allows remote loading from a memory chip) you might be able to just use their bootloader ??
“ Customized Optiboot bootloader allows reflashing Moteino/AVR boards from an external serial FLASH memory chip. This makes it possible to wirelessly program a Moteino remotely by first transferring the compiled HEX binary wirelessly (ex. with an RFM69 transceiver), then restarting the board to allow the bootloader to pick it up and reflash the atmega's program area. Copyright Felix Rusu (2013-2019), ”
“ Moteinos are compatible and can communicated with any other Arduino or development platform that uses the popular HopeRF RFM69 or LoRa transceivers, or even the older RFM12B. Moteino also comes with an optional SPI flash memory chip for wireless programming, or data logging.”
Great stuff!! I was hoping for a simpler solution (with hardware I have) but this will work. Thanks a lot. I’m favoriting the web site.