sola

sola

Electronic shelf labels (ESLs) are now used in many stores and available at very reasonable prices (5-10$ / unit) . These all seem to use ultra-low power eink display modules that only consume power when the content of the display is being changed.

E.g.: https://www.alibaba.com/product-detail/Wireless-transmission-zero-power-electronic-shelf_60256379521.html?spm=a2700.7724838.0.0.M2nZGP

In stark contrast, I still don't see any affordable e-ink modules available for Arduino projects. The 2.9" Adafruit module is 39$ which sounds ridiculous when you consider that a cheapo $10 ESL module contains more components and is still only quarter of the price.

Hopefully, one day ESL manufacturers will start selling their display modules standalone as well.

Until that happens: Has anyone seen a hack for any of the ESL modules so that one could use the display or the whole ESL as part of an Arduino / mysensors project?

This would give us access to affordable, ultra-low power display modules.

sola

Hi All,

Being hit by various problems with noname nRF24 radio modules, I have decided that I try to find a more trustworthy source for my radios.

Ebyte (cdebyte) seems to:

produce relatively affordable modules
uses original Nordic chips
has official store on Ebay and Aliexpress
has a proper English website with product pages, specs and manuals
Mysensors forums also seems to be positive around their products (from the limited number of forum entries found around their nrf24 products)

However, they have a fair amount of module types and I am unsure which one can be used for what roles in a Mysensors project (so I speculate here and I await your opinion and experience).

Range at 250 kbps data rate, prices from the official ebay/aliexpress store:

E01-ML01S
0.1 km range, PCB antenna, 0dBm, 1 mW power, non-shielded
through hole/SMD
$3.89 / 1pcs
$1.08 / 10pcs
role: node with short distance to gateway/repeater

E01-ML01D (red)
0.1 km range, PCB antenna, 0dBm, 1 mW power, non-shielded
soldered pins/DIP
$3.31
role: node with short distance to gateway/repeater

E01-ML01IPX
0.2 km range, IPEX antenna connector, 0dBm, 1 mW power, non-shielded
through hole/SMD
$3.89
role: node with short distance to gateway/repeater
notes: can have external antenna but still, 0dBm

E01-ML01DP4
1.8 km range, PCB antenna, 20dBm, 100 mW power, non-shielded
soldered pins/DIP
$3.69
role: node with long(er) distance to gateway/repeater

E01-2G4M13S
0.8 km range
PCB antenna, 13dBm, 20mW max power, advertised as PA+LNA, shielded
through-hole/SMD
$4.50
role: node with long distance to gateway/repeater

E01-ML01SP2
1.8 km range
both PCB antenna and IPEX antenna connector, 20dBm, 100mW max power, PA+LNA, non-shielded
through-hole/SMD
$3.9 / 1pcs
$1.97 / 10pcs
role: node with long(er) distance to gateway/repeater
role: gateway/repeater

E01-ML01SP4
2 km range
IPEX antenna connector, 20dBm, 100mW max power, shielded
through-hole/SMD
$3.89 / 1pcs
$1.97 / 10pcs
role: gateway/repeater
role: node with long distance to gateway/repeater

E01-ML01DP5
2.5 km range
SMA-k antenna connector, 20 dBm, 100mW max power, shielded
soldered pins/DIP
$3.89
role: gateway/repeater
role: node with long distance to gateway/repeater

E01-2G4M27D
5 km range
SMA-k antenna connector, 27 dBm, 500mW max power shielded
soldered pins/DIP
$5.89
role: gateway/repeater
role: node with long distance to gateway/repeater

If you have any experience with the above modules in any role in your network, please let me/us know.

UPDATE 2021-JUL-04:
It seems that experiences are very positive with these modules in the community.
The MySensors store now also lists two of these modules as the recommended radios.

sola

@Igor-Antolić @mfalkvidd

Great answers, thank you both.

sola

Thanks, I will try it out.

sola

Thanks for the link.

Still not cheap (1.44" for $12) but at least not outrageous like the Adafruit.

sola

It works, many thanks.

I used a 4K7 resistor as pull-up and it seems to be enough.

sola

I have ordered a set of E01-ML01S and intend to test them against my gateway.

@orhanyor: I would definitely expect the E01-ML01S to do better than a couple of meters. That is the range of the shittiest noname nrf24 clones (when they work at all).

sola

@bjacobse
Couldn't agree more.
This might just be the problem I face.

sola

I have managed to upload with a home made programmer (my Uno as an AVR ISP) and test the behaviour without the bootloader.

It seems to be very fast now even in the setup(), so I think this solves the problem for me perfectly. I guess it is now below 500ms, maybe even less.

Many thanks for the help.

sola

@rozpruwacz

Actually, I considered that as the fallback solution but I do not want to increase complexity if there is a robust, simple solution.

sola

I have built 2 nodes with E01-ML01S (the cheapest module) and I have pretty good experience with them so far.

I didn't have to use any capacitors to improve range, they are directly connected to some medium-quality Arduino Nano GND/3.3V.

One of them is a lighting controller node, ~3 meters from the PA/LNA gateway (+ a 30cm wall) on the same level as the gateway.

The other one is a repeter node and is ~10 meters from the gateway (+ a 20cm wall, same level as the gateway). In this case, radio orientation was important to get a good signal.

One of the test modules could communicate with the gateway through 2 walls and a the ceiling (steel-bar reinforced).

All-in-all, I am satisfied with the signal stability of these modules.

It is a bit finicky to solder the wires to the module because the pads are very small.

I always put some solder on the pads first and reheat when I attach the wires.

sola

@mmessiter Great stuff, congrats for the system.

sola

@korttoma Did you give power to the antenna side of the RXB6?

What is the distance between your receiver and the senders?

sola

I have ordered a set of E01-ML01S and intend to test them against my gateway.

@orhanyor: I would definitely expect the E01-ML01S to do better than a couple of meters. That is the range of the shittiest noname nrf24 clones (when they work at all).

sola

@Nca78 I am planning to use a couple of repeater nodes to connect far-placed nodes to the gateway (on 250kbps).
Do you think nrf24 is bad for this?

sola

@monte
Thanks, good to know.
I am considering the E01-ML01SP2 (the little brother) as a workhorse since it is relatively cheap, has both PCB and external antenna and can do 100mW. I would mostly try to use it without the external antenna and would populate the IPEX only in problematic cases.

sola

Hi All,

Being hit by various problems with noname nRF24 radio modules, I have decided that I try to find a more trustworthy source for my radios.

Ebyte (cdebyte) seems to:

produce relatively affordable modules
uses original Nordic chips
has official store on Ebay and Aliexpress
has a proper English website with product pages, specs and manuals
Mysensors forums also seems to be positive around their products (from the limited number of forum entries found around their nrf24 products)