AVR Freaks

EOL

https://www.mouser.com/ProductDetail/RF-Digital-Wireless/RFD21733?qs=%2fha2pyFaduh2vXRhnAgjxY30Nhn8WJhfJZnpmOrzy4E%3d

Simblee might be considered as the follow-on to RFDP8; scratch, Simblee is EOL : https://www.arrow.com/en/products/rfd77101/rf-digital-corporation

RFDP8 and Simblee are coin cell friendly.

 

RFDP8 couldn't withstand Bluetooth 5 with its range enhancements and mesh network.

Seems each Bluetooth 5 manufacturer has SPP over Bluetooth Low Energy; most have an SDK so can port the application into their Bluetooth 5 SoC.

 

Edit: scratch

 

9600bps to 115200bps UART plus one signal for command mode for 1.6km LoS :

Linx Technologies - Basic Configurations for Sending Data with the HumPROTM Series RF Transceivers

via HumPRO™ Series RF Transceiver Module - Linx Technologies

UART plus more discretes : 

Transparent RF Modules Archives - Linx Technologies

 

You're welcome.

Approximately 1KB/s for Microchip Bluetooth Low Energy modules with transparent UART (SPP over Bluetooth Low Energy) [SPP over BLE]; greater speed by other manufacturers modules.

BLE advantage : operator's interface is a PC, tablet, or smart phone

BLE disadvantage : short range

Wi-Fi can have an extended range of 1km to 100km by antenna gain; likewise with Bluetooth.

A university may have spare 2.4GHz directional antennas; one can make an inexpensive 2.4GHz directional antenna.

Given system RF gain and range and heights and estimated loss (vegetation, walls, etc), BER or SNR can be computed by an RF link budget calculator (some are on public web servers)

Some Microchip BLE modules recently obtained a Bluetooth 5 certification (range increased, Wi-Fi interference decreased, enhanced mesh networking); looked at BM71 and BM78.

BM71 : transmitter power = 0dBm typ, receiver sensitivity = -90dBm typ, 3.0V typ, 10mA typ (coin cell)

BM78 : transmitter power = 0.5dBm typ, receiver sensitivity = -92dBm typ, Li-ion typ with 3.3V 50mA LDO for the external MCU

Cypress Semiconductor EZ-BT^TM :

CYBT-353027-02 : transmitter power = 9dBm typ, receiver sensitivity = -96.5dBm typ, 2.3V .. 3.6V, up to 60mA typ

Might be able to reach the required range with some modules as-is; Microchip modules would have an external antenna with significant gain.

Mesh networks have range due to modules relaying packets; a mesh network has an IP capability by a gateway.

 

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Cantenna - Wikipedia

How to build a tin can waveguide antenna

Bluetooth | Microchip Technology

BM71 - Bluetooth Module - Wireless

BM78 - Bluetooth Module - Wireless

BM70/71 Bluetooth Low Energy Module User's Guide

(page 16)

1.1.2 System Operation

The BM70/71 module has two main configuration options which affect the overall BLE and hardware behavior available to the host. The two configurations are:

• Auto Operation Configuration: Auto Operation restricts the available BLE operation by only allowing the BLE peripheral to act as a raw data pipe. This is compatible with hosts who only require the BM70/71 module to act as a virtual UART cable between the host and the remote peer device

• Manual Operation Configuration: Manual Operation provides the host the most functionality and control over the BM70/71 BLE protocol and operation. This configuration is used by a host to leverage the flexibility and feature set offered by both the BLE protocol and the BM70/71 module

BM7x are not extendable (added functionality) though are configurable (UART, discretes); Microchip has BLE SoC that are extendable via Atmel Studio 7.

CYBT-353027-02: EZ-BT™ WICED® MODULE

via

EZ-BLE and EZ-BT Bluetooth Modules

...

 

Additional Module Solutions Coming Soon

 

...

CYBT-483039-02:  Having range issues?  The CYBT-483039-02 module is certified up to +20 dBm output power and is targeted at a BLE connection range >1km.

...

 

EZ-BLE/EZ-BT Module Highlights

...

• Long-range BLE options for up to 400 meters line-of-sight communication

...

... and EZ-Serial

...

• Wide operating voltage (1.9 to 5.5 V)
• Industrial (-40°C to +85°C) and Extended Industrial (-40°C to +105°C) temperature range options

 

Not much RF Digital product at distributors.

Mouser has some stock of one RF Digital nRF24LE1 module but that's without RF Digital's RFDP8 firmware.

Is there a nRF24LE1 SDK?  Yes

Otherwise, an RF megaAVR and its mesh networking stack for range (or, gain by a power amplifier and/or antenna)

 

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https://www.mouser.com/ProductDetail/RF-Digital-Wireless/RFD21734?qs=%2fha2pyFaduhYv4A8eWEj85m%2fAf%2fA0yI1h1dB%252blHyzvM%3d

nRFgo SDK / 2.4GHz RF / Products / Home - Ultra Low Power Wireless Solutions from NORDIC SEMICONDUCTOR

ATmega64RFR2 - Wireless Modules - Wireless (on-sale at Digi-Key)

https://www.microchip.com/mymicrochip/Reports.aspx?type=cpn&filter=atmega128rf

 

Edits: nRFgo, Digi-Key

 

I believe it's short for ""Attention". That is "Oi modem, I'm about to ask you to do something"

 

EDIT: yup, Wikipedia agrees: https://en.wikipedia.org/wiki/Ha...

 (also called the AT commands: "AT" meaning 'attention')

AT commands are sent in command mode, ie. commands to the modem however if the ATO command is sent (Return to Online mode)

Then the data stream follows the command as that command string exits command mode.

 

Jim

 

IIRC, there's no complete follow-on to SPP.

Yes

Android, Google Play, Microchip Bluetooth Data :

...

 

Supports the following BLE profiles/services: ...

4. Custom Serial Chat (custom profile) 

...

 

...

 

3. BM70 /BM78 /BM64  :
Discover and connect LE device. Transfer text typed in the app to peripheral device. Transfer text file data, send and receive across the device and phone

 

...

similar for iOS

 

Mark,

 

I would say you are clearly not old enough but I believe you are. You may remember back in the pre-internet days of "bulletin boards" when we connected up "acoustic couplers" to telephone handsets and we made connections at 300 baud, 1200 baud or the luxury of 2400 baud that the modems we used then generally all implemented the "Hayes command set". That is a method where the modem switched on in command mode. You "set it up" by sending it AT command likes ATE1 (switch command echo on), ATS0=1 (set number of rings before it "hooks" the line to 1) etc etc. At some stage you finally would ATD012345678 and it would dial that number. The modem at the other end would put out "calling tone" and the two modems would latch on to each other. The modem then switched to "data mode". So now you stopped sending "ATxx" command and you typed real things like "hello world" (or initially probably an ID and password) and that data streamed through to the other end. If you needed to get back into command mode you would type three +++ signs to tell the modem "stop sending everything I type to the other end but return to listening for AT sequences so I can tell you to do something". You might then type ATH0 which means "unhook the line" - that is "hang up". While the Hayes company failed to get a patent on their AT command set the one bit of this whole thing they did patent was the "+++" thing to get back from data mode to command mode. In fact, on the basis that you might be sending "+++++++..." to the other end for real they made it so it only switched with "+++"<1 second of no activity> and that's the bit they patented.

 

Now all the people who write bulletin board software and terminal software and so on at the time added "Hayes compatible" to their code by having it setup and then send the right sequences of ATxxx at the right moments. So other modem manufacturers said "we want to be compatible with bulletin board software XYZ or terminal program ABC" so rather than thinking up some other way to control their modem pretty much everyone copies what Hayes had done and so there were tons of Hayes compatible modems so "AT commands" became a bit of a "standard" but Hayes still owned the patent on the +++ then delay thing - not sure how many people they sued but most cloners got around it by not having the delay after the three +++.

 

AT was such a part of the whole communications scene in those days that it persists to this day. Many devices that want to setup a "data channel" in some way still use ATxx to get things setup though it has now involved adding a whole lot more commands than the 20 or so that the original Hayes modem had. When mobile phones started to offer data links (SMS and then GPRS and so on) they extended their command range so that you could now do things (conceptually) like ATSMS=07214387,"Hello folks" and it would send an SMS to that number of ATHTTP=www.avrfreaks.net (obviously not quite THAT simple) to make TCP/IP links over GPRS and so on.

 

Then when Bluetooth devices came along they also took on ATxx so to control a Bluetooth speaker (say) you might conceptually do something like ATVOL=11 to set the audio volume etc etc.

 

So from humble beginning Hayes and their AT commands are all pervasive to this day. 

 

I remember 30..40 years ago contemplating what "AT" might mean at the time - I think we all agreed it was "ATtention" as in "Attention, I'm about to ask you to do something". To find/verify that was simply a case of googling "AT command set wikipedia" to find the page I knew must exist.

Yes

Arduino with RN4870/1 | Martyn Currey

...

(1/4 page)

Power the module, then use a BLE scanner app to find the beacon. Here I am using Android BLE Scanner by Bluepixel Technologies LLP but there are many similar apps.

...

 

Talking to the RN4870/1

[USB UART to RN4870]

...

“GNR” command
“GNR” gets the name of a connected device. Of course, for this to work the module has to be connected to something. With the serial monitor still open. Use the BLE scanner app to connect to the RN4870.

...

 

First Communications

...

Start the BLE Scanner app, if it does not automatically start scanning, hit the Scanner button at the bottom. You should see the RN4870 appear in the list.

Hit the CONNECT button, after the connection is made, select the Custom Ser[v]ice

...

We can now try sending data to the serial monitor.
["hello", "hello to you"]

...

 

Notify or Indicate?

...

 

Connecting Two RN4870 Modules Together

The RN4870s have a transparent UART layer built in. This means it is easy to get them connected and start sending data. This is very similar to how the HM-10s (and similar modules) work, and, if this is all you need you might as well go with HM-10s. They are cheaper and come on hobbyist friendly breakout boards.

...

 

Updating the Firmware

...

After updating, use a BLE scanner app to check the default services and characteristics.

 

...

 

[comments]

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http://www.martyncurrey.com/arduino-with-rn48701/#comment-13786 by Martyn

The RN devices only support single connections. For a piconet you would need to use devices like the BTLC1000 and SAMB11. These support up to 8 simultaneous connections.

...

 

http://www.martyncurrey.com/arduino-with-rn48701/#comment-14150 by D

...

I’m considering using the RN4871 module as serial passthru device to transfer data from an old serial instrument (TX only, no flow control) to a tablet.

[Question]

[HM-10 and EMI]

[Martyn's reply]

[iOS is Bluetooth 4 and sub]

...

 

http://www.martyncurrey.com/arduino-with-rn48701/#comment-14309 by jack kemski

[RN4870 firmware 1.30 - spontaneous disconnects; work-around is to reboot]

...

My question is, for a serial UART application, only needing to transfer small amounts of serial data back, and forth, what modules would you recommend?

[Martyn's reply]

...

If power is a concern look at BLE modules sans breakout board. I’ve had good results using the HM-11. Good connections and fairly low power use. There are better options is power consumption is critical though.

 

...

via https://plus.google.com/u/0/106109247591403112418/posts/FsfJEkuVoV8

 

Advantage BM70 and BM71 is the full industrial temperate range (to -40C)

RN4870-I, RN4871-I cover the complete industrial temperature range but only with the on-board chip antenna.

• transparent UART is 10 kbps (iOS®9) max

(with thanks)

Disadvantage BM70 and BM71 is no ASCII interface.

https://www.microchip.com/design-centers/wireless-connectivity/bluetooth

 

Edits: ASCII, strikethru

 

Is there not a school of thought that AT meaning attention was a backronym and that AT was chosen to be easy to auto baud on.

It's true that "AT" makes auto-baud easier so you may be right but my very blurred and distant memory is that there was "AT" before there was auto-baud. Or did I just dream that? Did Hayes modems really auto-baud right from the very start?

 

I know it's not definitive but Wikipedia says:

 

https://en.wikipedia.org/wiki/Ha...

 

where it uses the term "happens". Though maybe it was by clever design?

Laird LT1100 (part PRM240) is an alternate.

Throughput is 50Kbps with FEC or 100Kbps without FEC

2.0V .. 3.6V, 230mA peak TX, 30mA peak RX, 8mA idle, 300nA sleep

Receive sensitivity = -89dBm for BER of 10^-6

Transmit power up to 23dBm

EIRP up to 29dBm by 6dBi antenna

2dBi dipole antenna range is approx 800ft (244m) indoor to 3.2mi (5.1km) outdoor

 

User Guide - LT1110 Module.pdf

(page 12, middle)

Tip: Can I implement a design using just TXD, RXD, and GND (three-wire interface)?

Yes. However, it is strongly recommended that your hardware monitor the CTS pin of the radio. CTS is taken High by the radio when its interface buffer is getting full. Your hardware should stop sending at this point to avoid a buffer overrun (and subsequent loss of data). You can perform a successful design without monitoring CTS. However, you need to take into account the amount of latency the radio adds to the system, any additional latency caused by retries, how often you send data, non-delivery network timeouts, and interface data rate. Laird can assist in determining whether CTS is required for your application.

via  LT1110 Series | LairdTech

 

The following arrived today at Microchip Developer; the listed Bluetooth 5 module is BM70.

Android™ Bluetooth® Low Energy (BLE) App Development For BM70 / RN4870 - Developer Help

(bottom of 3rd paragraph, 4th paragraph)

The BM70/RN4870 module acts as a BLE peripheral which can discover, connect, and communicate with the Android app.

The MCHPTransparentUART Android Studio app package is provided with this help guide. This app runs on the Android OS and connects and communicates with a BM70/RN4870 BLE module using the Microchip Transparent UART Service. Android Studio 3.2, with compile SDK version API 28 (Android 9.0 Pie), was used for the app at the time of creation. A user must migrate as needed for newer versions of Android Studio and API levels to be up to date. The BLE APIs discussed as part of this document are from Android API level 21 and up. The BLE APIs in Android API levels lower than 21 are not discussed.

 

...

 

[BOM : hardware : BM70, Bluetooth 4.0 and sub, Android 5.2 and sub; software : Android Studio, MCHPTransparentUART, terminal emulator]

 

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Android Service for BLE - Developer Help

 

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BM70 - Bluetooth Module