Do processors arrive from Digikey already with Bootloaders? Is an Xbee overkill? - Page 1
Forum section: electronics / projects

author: Chad1
author_rank: Contributor
timestamp: April 22, 2015, 03:19:33 am
content: Hi all,Let's say as a hobby project I'm designing a simple wireless alert system composed of two boxes. When a button on Box1 is pressed, an LED on Box2 (located in another room) blinks. A subesquent button press on Box2 stops the blinking LED and notifies Box1 that the "message" was received by blinking an LED on Box1.I'm very inexperienced with Xbees, how to integrate them in a system, and wireless communication in general. As such I'm hoping someone can help me answer the following questions:1. Would an Xbee Series 1 be overkill? Are there cheaper, simpler alternatives for this application?2. Assuming the above are the only requirements, would a microcontroller be required for both boxes?3. Assuming a microcontroller is necessary, which would be the simplest one I could get away with using? (I'm used to working with Propellers. Eight cores definitely seems like overkill and more expensive than necessary.)Thanks a lot!

author: LabSpokane
author_rank: Super Contributor
timestamp: April 22, 2015, 04:04:48 am
content: The ESP8266 is the cheapest way to go right now. If you're new to uC's, it could be a bit tough since the documentation is a bit fragmented. You could order a couple 8266's off eBay from a good supplier and try programming them with the Arduino IDE. Since you only need two I/O's on each side, that would fit the bill.That said, there's nothing wrong with the Xbee.

author: eneuro
author_rank: Super Contributor
timestamp: April 22, 2015, 08:19:03 am
content: There are also cheap 433MHz RF modules which sends 1bit and 8pin Atmel AVR ATTiny85 with a few lines of C code should do the job, Alarm source could transmit its state on 1 pin and look for button response on another-the same for the button. So, we could have continous data link between alarm and receiver. When we add encryption to those bits, eg. based on RTC lock time the same on both devices, than we are doneThere is video with one such cheapy 433MHz RFs.Note, there is no need to use them with bloody big ass Arduino, but... for eaxample small 8pin ATTiny85 and a few lines of C code.The only question is those cheapy transmiter/receiver 1bit modules marked as 433MHz are somehow paired with matched frequency, so we could buy 2x transmiter/receiver and have slightly different working RF frequency, so we could use both transmiters and receivers at the same time without any interference or more fancy protocol needed: receivers listen to the same frequency transmiter and when there is no any signal present at randmom intervals start its own transmiter, than turns off and for some time and starts listen to 433MHz signals around.But ok, without MPU those cheapy 1bit modules could work for if we had them paired working at different RF frequencies-probably not a cost effective, but for sure simple.Investigating such thing too-I need my dog to activate alarm using dog sound detection and than have a choice to dismiss or activate other systems like.... open dog cage with remote button without leaving a house

author: kripton2035
author_rank: Super Contributor
timestamp: April 22, 2015, 08:27:19 am
content: I would go with two esp8266 modules for thatthe 433 (or even 868MHz) is very crowdy these days, especially if you live in a big citythe wifi modules will be more robust.no need for an arduino, 2 modules, the node-mcu firmware flashed inside, and some lines in lua langage (similar to basic)will cost you total 6 or 7$ shipped ...

author: Chad1
author_rank: Contributor
timestamp: April 24, 2015, 01:25:36 pm
content: Thanks for all the replies! I definitely have some better ideas for this project now.One other question: If I order a Pic or Atmel processor through a place like Digikey, do they arrive ready to program? Or do they need Bootloaders and other things first? I'm used to incorporating Propeller processors in my designs and they arrive ready to program, no bootloader or extra steps necessary.