# HMI -> Microcontroller? -> PCB I/O

1. Jan 12, 2016

### Bikkehaug

Hello

I want to make a HMI that monitors i/o through a microcontroller/fpga/something.

The problem I've come across is to figure out what's going to interpret/read i/o at the end of this system. For what it's worth, it's going to read i/o from "props" used in so called Escape Rooms - so they need to be fairly small and support wireless communication (bluetooth, xbee, Zigbee or something).

Essentially, these cards in my sketch, all they need to do is send i/o information wirelessly to the microcontroller.

For instance, I have a prop where a button has to be pressed in order for it to be solved. My goal is to send a signal to the microcontroller that the correct button has been pressed, and then display this on the HMI (windows forms application will be used for this).

Any ideas for what to use as a "card"? Keeping in mind price, size and wireless strength.

Thanks.

2. Jan 12, 2016

There are a few low cost RF / Blutooth modules that actually run their own uC - and have a few GPIO on them - so you will need to define clearly how many Digital I/O per "card" is needed.
"Keeping in mind price, size and wireless strength." - we have no idea what your perspective on any of these parameters are: $20, 4" Square and 100Meters - line of sight - through walls - etc.. 3. Jan 12, 2016 ### Bikkehaug The exact number of I/O has not been decided yet. For price I was thinking 10-15$.
Size equals or less than 1,5" square.
At least 40Meters through walls.

4. Jan 12, 2016

40M at that price and size I think will be tough. == http://www.mouser.com/ProductDetail/Adafruit/2471/?qs=GURawfaeGuAoxPWz4nSJYg%3D%3D&gclid=Cj0KEQiA5dK0BRCr49qDzILe74UBEiQA_6gA-laMx8Gr5s6pgN6moE9T7yBHKIzO8luleugH8S0At-QaAuLZ8P8HAQ [Broken] looks interesting - the small antenna and power on the small board will be the trick. (Even a WIFI router can have trouble at 40M with walls)

Last edited by a moderator: May 7, 2017
5. Jan 14, 2016

If I set the price to 30-40$per unit, would you recommend Xbee, Or something else? 6. Jan 14, 2016 ### meBigGuy 7. Jan 15, 2016 ### Windadct Or this P-Zero ( photon) - use a cloud service ( included) and a phone as HMI... 8. Jan 17, 2016 ### rbelli1 These: http://www.digikey.com/product-detail/en/RF200P81/746-1022-ND/2804294 work well. They are a bit higher priced than you are looking for but you program them in python and they can autonomously react to IO and talk to each other. They connect to a PC through a USB dongle. If you roll your own interface into the PC module (they have stdio like functionality) you can have unlimited devices for no extra cost. If you use the python module for the PC you will have to buy a$100 license if you go above 10 units. This is also available for Linux and can be deployed on ARM boards. They also mesh but you have to be careful about which ones build the mesh if you go above about 50 units.

They also have a very low power sleep mode if you need to put them on batteries.

BoB