nRF5 action!

NeverDie

Here's the really good news. I tried a very quick range test with the above configuration, and it seems to be noticeably better than with two nRF24L01's. I check the datasheets, and, indeed:

nRF24L01: -85dBm sensitivity at 1Mbps
nRF52832: -93 dBm sensitivity, 1Msps nRF mode

So, for an nRF52832, that's an 8dBm improvement in link budget just from improved sensitivity alone. i.e. more than twice the range. Nice. :)

NeverDie

Looks as though the nRF52840 will have the same nRF mode receive sensitivity. However, it will have a receive sensitivity of -103dBm in 125ksps BLE mode. which is huge.

NeverDie

It's somewhat strange that the F-antenna never caught on with the nRF24L01, which typically used some kind of meandering antenna.
alt text

However, as proven by the ESP8266's evolution, the F-antenna is superior.
alt text
So, its presence in at least some of the nRF52832 implementations (such as that pictured below) should help as well.

gohan

I found it on some modules from Sunfounder on red PCB but they have fake nrf24 chip and still performed bad but a little better than the other chinese clones (range 7 meters indoor instead of 5)

NeverDie

Presently the parts cost is higher for an nRF52832 (and surely for an nRF52840) than for an RFM69 plus an atmega328p. So, I'm struggling to justify it.

Nca78

@NeverDie said in Minimalist SAMD21 TQFP32 Pro Mini:

Presently the parts cost is higher for an nRF52832 (and surely for an nRF52840) than for an RFM69 plus an atmega328p. So, I'm struggling to justify it.

With only 5$ for the EBytes modules there's not much difference I think ? And for that you have a smaller size, easier soldering (compared to SMD atmega), incredibly more capable hardware that's really future proof for both MCU and radio module, lower power consumption for TX and even more for RX, ...

NeverDie

@Nca78
You're right. Especially after outfitting the atmega328p with an RTC, the cost is more of a wash. I think the RFM still wins on range, but maybe the 832 will be "good enough"...

NeverDie

I'm guessing that if I were to desolder the rFM52832 from the DK, then I could use the DK to program other chips using the SW pins by using the J-link that's part of the board.

NeverDie

@gohan said in Minimalist SAMD21 TQFP32 Pro Mini:

I found it on some modules from Sunfounder on red PCB but they have fake nrf24 chip and still performed bad but a little better than the other chinese clones (range 7 meters indoor instead of 5)

Interestingly, the antenna on the DK is sort-of hockey stick shaped. I guess they didn't need to compress it, since the board is so large anyway.

Terrence

am reading your findings with great interest. Thanks for the updates.

d00616

@NeverDie said in Minimalist SAMD21 TQFP32 Pro Mini:

You're right. Especially after outfitting the atmega328p with an RTC, the cost is more of a wash. I think the RFM still wins on range, but maybe the 832 will be "good enough"...

The question is, when 832 modules are available. After announcing the nRF52832 with its preview DK, I have waited from 06/2015 to 08/2016 until modules are available for an acceptable price at aliexpress or ebay.

I think the atmega is a slow 8-bit MCU with less RAM. The limited RAM requires to transmit additional nonce packages, when signing is enabled. SoftSigning hashing is 76 times faster. A faster CPU allows to shorten the active time:

atmega328 14000µs
nRF51 1739µS
ESP8266 380µS
nRF52 183µS

The NRF24 has problems with clones, range and the limitation of packages to 32 bytes. The nRF52 allows to change the packet format to support >32 bytes packages.

At the moment sleep modes are only implemented for 328 and nRF5.

OTA updates are available for 328 and ESP8266. For nRF5 it requires to implement a boot loader. The internal flash should have enough capacity to store a simple bootloader and a firmware update.

If you plan to do a lot of writes into EEPROM the 328 has a real EEPROM. The SAMD requires an external EEPROM, the nRF5/Teensy/STM32F emulating the eeprom in Flash. The nRF5 is using the NVM driver, which allows much more writes to the emulated EEPROM. The price for NVM is some time for log cleaning after some hundreds writes.

IMHO the best MCU for creating new battery powered sensors is the nRF5 stating with a ~3€ board, if required in combination with RFM modules.

@NeverDie said in Minimalist SAMD21 TQFP32 Pro Mini:

I'm guessing that if I were to desolder the rFM52832 from the DK, then I could use the DK to program other chips using the SW pins by using the J-link that's part of the board.

I think it's simpler to use one of the ST-LINK v2 clones. The DK board should be good for development, debugging and current measurement.

NeverDie

@d00616 said in Minimalist SAMD21 TQFP32 Pro Mini:

I think it's simpler to use one of the ST-LINK v2 clones. The DK board should be good for development, debugging and current measurement.

What exactly do I need to do to get it work? I tried it from Windows, and failed. I seem to recall you said you got it to work from Linux after changing a definition. Would you mind showing the steps, or providing a link on how to do that?

NeverDie

@d00616 said in Minimalist SAMD21 TQFP32 Pro Mini:

IMHO the best MCU for creating new battery powered sensors is the nRF5 stating with a ~3€ board, if required in combination with RFM modules.

The board you linked to is an nRF51. Which do you prefer? nRF51 or nRF52?

NeverDie

Looks as though the nRF52832 beats the nRF51832 on Rx sensitivity at 1mbps. The nRF51832 is:
• -90 dBm at 1 Mbps
versus -93dBm at 1Mbps for the nRF52832.

On the other hand, the nRF51832 has -96dBm receive sensitivity at 250kbps, and the nRF52832 appears to lack that mode altogether. So, in a way, that make sthe nRF51832 seem a bit more attractive on range, even if one has to pay a price on bitrate.

NeverDie

@d00616 Now that you mention it, that board you linked to ( https://www.aliexpress.com/item/BLE4-0-Bluetooth-2-4GHz-Wireless-Module-NRF51822-Board-Core51822-B/32633417101.html?spm=2114.search0104.3.18.Q9naea&ws_ab_test=searchweb0_0,searchweb201602_5_10152_10065_10151_10068_10130_10084_10083_10119_10080_10082_10081_10110_10178_10136_10137_10111_10060_10112_10113_10155_10114_5360016_10154_438_10056_10055_10054_10182_10059_100031_10099_10078_10079_10103_10073_10102_10120_10189_10052_10053_10142_10107_10050_10051,searchweb201603_5,ppcSwitch_4&btsid=f45d662b-6a09-4449-9bee-1ea58d9beab8&algo_expid=53f99b5d-bb10-4b34-a548-2a3e4c0cd96e-2&algo_pvid=53f99b5d-bb10-4b34-a548-2a3e4c0cd96e ) would be an interesting way to control an RFM69, especially if it could do an OTA sketch uploade. Can it?

d00616

@NeverDie said in Minimalist SAMD21 TQFP32 Pro Mini:

The board you linked to is an nRF51. Which do you prefer? nRF51 or nRF52?

I prefer to use nRF52 controllers when the price doesn't matter.

@NeverDie said in Minimalist SAMD21 TQFP32 Pro Mini:

Now that you mention it, that board you linked to would be an interesting way to control an RFM69, especially if it could do an OTA sketch uploade. Can it?

OTA sketch upload is on my todo list, but not at the first position ;-)