AVR + IEEE 802.15.4 (<1GHz) transceivers

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I'd appreciate it if someone could offer a couple of suggestions about pairing up an AVR MCU (I'm thinking about using the MEGA162V-8PU ) to a general ISM < 1GHz (transceiver), and the ATTINY85 on the other end (with another transmitter).  Architecturally, my system is similar to an RF garage opener. There is a base station (using the MEGA162V-8PU) that has 2 sensors connecting to it. In terms of the preferred PHY protocol for the transceiver I was thinking about using the IEEE 802.15.4 (LRWPANs) as it allows for both 'peer-to-peer' and/or 'star' network designs. 

 

I've been scouting the Internet for potential solutions/ideas. There are plenty of options out there, but I can't seem to find the right one for me. Firstly, most MCU+Rx/Tx IC solutions don't come with enough GPIO ports. This makes it hard (if not impossible) for me to use any of the ATMEL's  all-in-one options (such as the AT86RF212B) - especially for the base which needs at least 3 or 4 push buttons an LCD module, and a couple of relays. In my mind using a single-chip (MCU+Transceiver) solution would be beneficial for multiple reasons (heat, power consumption, PCB space, etc.), but I don't think there is anything available for my number of GPIO pins, correct? 

 

For the sensor I could try to go with only an MCU + transmitter as it only has to capture data and send it back to the base (one-way communication). Has anyone designed something similar before? 

 

Any ideas/suggestions are very much appreciated. Thanks much in advance.   

Last Edited: Thu. Apr 20, 2017 - 03:16 PM
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muzycales wrote:
especially for the base which needs at least 3 or 4 push buttons
If it helps you do know you can put multiple buttons on a single ADC input if they can switch a resistor ladder to vary the voltage according to which button is pressed (reading multiple presses can be tricky though).

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Should this be moved to the 802.15.4/ZigBee  forum?

John Samperi

Ampertronics Pty. Ltd.

www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

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clawson wrote:

muzycales wrote:
especially for the base which needs at least 3 or 4 push buttons
If it helps you do know you can put multiple buttons on a single ADC input if they can switch a resistor ladder to vary the voltage according to which button is pressed (reading multiple presses can be tricky though).

Check out the common LCD/keypad shields for Arduino for how to do your push buttons with one pin.

There are a LOT of smart freaks here that can help you design using a minimum of port pins if you ask and supply a design spec to work with.

Good luck with your project.

Jim

 

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Thank you for your answers. I'd like to add a couple of things here: the number of push buttons is somewhat irrelevant to my underlying problem. Sure, I could try to implement a voltage divider and use the Analog-to-Digital Convertor to read their voltage. The real issue is that most of these on-chip solutions (Rx/Tx+MCU) ICs do not have enough GPIO pins to handle however many pins the base would require. The LCD module by itself needs at least (If I'm not mistaken) 7 or 8 pins. So the base will need a separate MCU + a Transceiver. The sensors could (perhaps) use some of these integrated solution because they only need to read the sensor (so in theory one GPIO pin should suffice). 

 

There are a LOT of smart freaks here that can help you design using a minimum of port pins if you ask and supply a design spec to work with.

That's kind of what I was trying to do :) ... I was hoping someone would help me to choose the right transmitter and transceiver for this project (for the base and sensors)  

 

-----

Kind regards

Last Edited: Sat. Apr 22, 2017 - 02:07 AM
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I am using DIGI modules:

 

https://www.digi.com/products/xb...

 

YOu can get them with a PCB antenna(which reduces the range).  Super simple to use.  Expensive, but you only need a USART to talk to them.

 

Jim

 

Wondering if this should be moved to the Wireless forum as King S. says

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