eRIC Nitro [150308]

This project is the result of the LPRS contest run last year. The winner's project is to be finalized by and published in Elektor. So here we go.

This project is the result of the LPRS contest run last year. The winner's project is to be finalized by and published in Elektor. So here we go.

eRIC Nitro is an Arduino compatible board with a Smart eRIC wireless module on it. The Arduino part makes eRIC even smarter. In case you don't know eRIC, check out his profile.

The eRIC Nitro board is more or less part of an Internet connected weather station project by contest winner Alex Robertson. We will make it into an open source, open hardware board with supporting software.

Update 16/09/2015

The prototype PCBs have arrived (see photo below), components too, so we can start building our first test sets. There will be eRIC4 (433 MHz) and eRIC9 (868/915 MHz) boards.

Some silkscreen writing has to be made a bit more readable.

Update 7/10/2015

Assembled and tested a couple of boards. Discovered an incorrect footprint in the process and so the PCB has to be modified. Modding the boards to obtain working prototypes was not too hard. Everything has been validated (except for the PCB), all tests were successful and wireless communication between two boards has been established.

PCB changes:

Switch S2 rotated 180 degrees
Silkscreen more readable
Changed copper fill under radio module to avoid short circuits

New PCBs have been ordered, black ones this time. We want cool-looking boards.

Update 8/10/2015

Now on GitHub

Project Elements

First version of the PCB, top & bottom. (JPG, 779.7 KB)

Our test set with number two on the ISP programming/test rig. (JPG, 293.45 KB)

Discussion (5 comments)

Alvaro Alvarez Alvarez 8 years ago

Dear all,

Last week I bought a set of Elektor (arduino) Nitro boards and ERIC4 transceivers.
I have worked with ERIC4 prevously with no problem at all (DK from LPRS).

The problem I have, is that the board is not working as explained on: https://github.com/ElektorLabs/150308-e ... g.V01.docx

1st step I try to perform as indicated in the guideline, is to access the ERIC4 through the FTDI cable (3.3V).
When I place the jumper between the K1 - RST and K1 - 0V, the easyradio companion discover option just go through the different bit rates, with no discovery results.
If I remove the jumper, at 9600 bps it detects the ERIC4, listing the OS version, up to the BSL line, and the easyradio companion crashes, and a windows error window appears, telling that the software has to be closed.

easyradio companion is working correctly when instead of the Nitro, I use the DK board from LPRS.
The strange thing is that the soft starts (then crashes) to recognize the ERIC4 without the jumper between RST and 0V, no way to dfind it with the jumper.

Has anyone the same problem?
How do you solve it?

I tried in different PCs with similar results

Thank for your kind help and attention

Richard Hathaway 8 years ago

Thank you Alvaro for highlighting the error in our documentation we will edit this and re-submit to the LPRS website.

BR

Alvaro Alvarez Alvarez 8 years ago

BTW, Thanks for all the help and replies!

Alvaro Alvarez Alvarez 8 years ago

I found the origin of my mistake:

On doc http://www.lprs.co.uk/assets/media/downloads/LPRS%20IoT%20Design%20Contest%20Entry.V06.pdf

is said that in order to make use of the easyradio companion utility is required to "put S2 in the middle position. You will also need to put ATMega 328 into reset by connecting K1 pin /RESET to 0V"

while in the Elektor magazine, 01/2016, is reported that

"you maut force the ATMega 328 into reset by connecting K2 pin /RESET to 0V (with a jumper for instance)"

I checked that the instrucions given on the first doc (one allocated in the lprs web) are INCORRECT, and the jumper must be placed between RFS and 0V pins on K2, NOT on K1!

BR

ClemensValens 8 years ago

The problem is probably due to confusion. To make this work you must connect the pin labeled RES on the board to GND. These two pins are next to eachother so all you need is a jumper. The RES pin is connected to the MCU reset pin, the pin labeled RST on the board and on the other connector is the eRIC reset pin. So if you keep RST low the eRIC module will not work.

remotesensors 8 years ago

Just to clarify - you need to hold Arduino RST pin to 0V. Also, try a FTDI header which puts 5.0v on the Nitro Vdd, but don't exceed 3.3v on on the other FTDI pins e.g. Rx, Tx etc.

remotesensors 8 years ago

Hello Alvaro,
you do need to connect the Arduino reset pin to 0V for the duration you are connecting to the eRIC module with the companion software as this puts all of the ATmega328 pins into high impedance state. I think this is why you were able to discover the eRIC when you held the RST switch down as it serves the same function. Also I found I had better results when using a FTDI cable that gave 5.0V on the header Vdd instead of 3.3V. But don't exceed 3.3V on the other FTDI pins or you might damage the Nitro ATmega328. Let me know if this does not solve your problem.

I'd also be very intrested to find out your plans for the Nitro boards.

Alvaro Alvarez Alvarez 8 years ago

After several tries, I was able to "discover" the ERIC4, instead of pacing a jumper betwee K1 RST and 0V, by manually pressing the Rest Switch S1
This way, the LPR Esasyradio companion is able to run with no crash, and also I am able to configure baud rates, RF power and all parameters.

Once I umpress the S1 switch, I lost the possibility to reach the ERIC4

Is this the correct way?

Txs

7 Comment(s)

Frederick Vandenbosch 9 years ago

As requested via Twitter to LPRS/Elektor, I was wondering if you had samples available for review.

https://twitter.com/Elektor/status/710035757126254592?cn=bWVudGlvbg%3D%3D&refsrc=email

Best regards,
Frederick

ClemensValens 9 years ago

Interesting, I'll see wah I can do. Please post your review here too.

1 Comment(s)

remotesensors 9 years ago

The Elektor eRIC Nitro github repository contains the eRIC Nitro board schematics and examples sketches (https://github.com/ElektorLabs/150308-eRIC-Nitro).

Attached here are 2 more example sketches (not yet in the repository) - 'eRIC_ping_client.ino' and 'eRIC_ping_server.ino'.

These simple sketches demonstrate a client Nitro board sending a ping message to a server Nitro board at regular 3 second intervals. On receiving a wireless ping message, the server returns it to the client. The client calculates and prints the round trip message time and prints out the signal strength of the received message at the client.

For simplicity, these examples don't use the eRIC UART Host Ready and Busy hardware handshake signals. And they don't check that the radio channel is free before transmitting over the RF interface. Both are easily implemented and will be shown in other sketches.

For this demo, you'll need 2 eRIC Nitro boards, both fitted with eRIC modules and antenna. Both modules must be the same type - either eRIC4 or eRIC9.

Use the Arduino IDE to compile and upload these sketches to the Nitro boards.

Another set of example sketches will be uploaded later to demonstrate the client board operating at low power.

terminalimages.png (66kb)
eRIC_ping_client and eRIC_ping_server sketches (68kb)

2 Attachment(s) 0 Comment(s)

remotesensors 9 years ago

The following diagram is the proof of concept schematic. It is based on my own experience of using a standalone eRIC and Arduino Pro mini board. Be aware that it has not yet been implemented and tested, and may change.

eric-nitro-poc-schematic-v01-1.PNG (183kb)

1 Attachment(s) 0 Comment(s)

remotesensors 9 years ago

Introduction

This is a 'proof of concept' design for my entry into the LPRS IoT design Contest (lprs.co.uk).

The advanced eRIC node board (the “eRIC Nitro” board) is for users familiar with the Arduino platform who also want easy access to low power ISM radio connectivity. See http://www.lprs.co.uk/easy-radio/eric/

This board offers the same low power, low cost and features of the open source Arduino pro mini board and includes an LPRS eRIC RF transceiver module for radio connectivity.

The eRIC Nitro board gives the user the advantage of the ready availability of existing open source Arduino development tools and libraries, and very importantly - the Arduino development community.

Key Features include,

LPRS eRIC module with a subset of eRIC signals brought out to user accessible pads on the PCB
PCB form factor similar to Arduino Pro Mini (see possible form factor at http://uk.rs-online.com/web/p/processor-microcontroller-development-kits/7617327/)
PCB pin pitch 0.1” (2.54mm)
ATmega328 processor with Arduino UNO bootloader with direct serial connection to eRIC module.
On board 3.3V regulator providing power to eRIC module and ATmega328 device
Header for FTDI friend connector, to allow ATmega328 programming from Arduino IDE and also to provide serial communication interface
Can be quickly deployed as a battery powered low power programmable RF node
Total current consumption in low power mode (MCU and eRIC) < 100uA (target?)

eRIC Nitro hardware requirements (proposal only)

RF module and antenna

eRIC4 or eRIC9 module (with extended command set - TBD)
Antenna connection either by connector on eRIC module, SMA connector at board edge or PCB pad for user supplied wire antenna

Microcontroller

ATMega328, package type MLF 32
Pre-programmed with 8MHz version of Arduino UNO bootloader

Form factor

Similar to Arduino Pro Mini in length and width

Physical connectivity

Option 1 – standard board
- 2 rows of 12 pin SIL holes
- 1 row of 6 pin SIL holes for FTDI friend
- Example in mage below (note opportunity to change design to bring eRIC pins out to pads)

remotesensors 9 years ago

Hello Dirk67, thanks for the question and the prompt :-) I created 2 very simple sketches which have been added to the elektor github area at https://github.com/ElektorLabs/150308-eRIC-Nitro/tree/master/Software/Arduino. One is called eric_ping_server.ino and the other eric_ping_client.ino. The client sends out a broadcast message and the server returns it (but also as a broadcast message). The client receives it and uses it to calculate the round trip ping time. I know this is not what you expect from a star or point to multipoint network example, but its a good starting point for pulling one together. I have since been working on a low power version of this which puts the eRIC and the ATMega328 on the Nitro board into low power mode (to be woken up by the ATMega watchdog), and also checks the airwaves are clear before transmitting. I'll expand this to include addressing so that the client ignores any message not intended for it and will post it here soon. This will be star / point to multipoint.

Dirk67 9 years ago

>>"I'll upload a demo Arduino sketch to this project area very soon ." I wanted to politely ask if you have already undertaken any activities in this direction? (star network / point-to-multipoint) ;-)

remotesensors 9 years ago

Hello Dirk67, I'm glad you find the article interesting. I think both eRIC and Arduino are a great combination. The eRIC modules contain an OS called "easyRadio Operating System", also known as "eROS". This is developed by LPRS, the manufacturer of the eRIC module. In this project we are using the stock OS which comes pre-programmed on the eRIC modules by LPRS . We have not modified it in any way for this project. The Nitro can support point to multipoint (star network) communication. I'll upload a demo Arduino sketch to this project area very soon .

Dirk67 9 years ago

Hello Alex, I just got the new Elektor 01/2016 (german) and found your eRIC Nitro Article within. I find it quite interesting especially the combination with an Arduino compatible MCU... What about point to multipoint solutions ? I would like to have one module as some kind of "central" or "host" and several other eRIC Modules as the clients (sensors / actors). Are there any solutions for this kind of scenario still using the stock "OS" on the eRIC modules ?