nRF52840 mini Dongle

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Hi,

 

For a running project I would like to have a nRF52840 based mini dongle (Logitech Unifying formfactor).

I found some parties who sell nRF52840 dongles but thy are to large.

Is there anybody who found a manufacturer selling this kind of mini dongles?

A second option could be to develop a mini dongle myself. Especially with the new WLCSP package it is not that difficult to design a dongle with a small formfactor. The only problem is the prize level of the dongle is to high for my project (or the volume is to low to reach a healthy prize level).

My second question is. Are the people here who have the same need for a small dongle, and are interested in collaborating to design and produce a mini nRF840 based universal dongle?

Mabey Nordic itself is also interested in collaborating in this idea?

I really think a nRF52840 based dongle could be very useful in many applications as it can handle multiple protocols in one device.

Please let me know your thoughts and who knows.

[awneil]

How about posting some links or pictures showing what you want (and, for contrast, what you don't want) ?

And some actual dimensions.

Ad said:

frankly look a little crappy

In what way(s) "crappy" ?

Ad said:

it is not that difficult to design a dongle

Do you have experience with doing that - especially the RF part?

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awneil said:

In what way(s) "crappy" ?

You have a point here. The appearance of a product is a matter of opinion. So I removed that statement.

awneil said:

Do you have experience with doing that - especially the RF part?

Yes, I have experience with RF design, build FSK and ASK transmitters and receivers from scratch in the past. The RF part of the nRF50840 is not so hard if you follow the reference designs and follow high speed design methodology.

Some tips:

1. Keep your traces short.
2. Control the impedance of your tracks @50Ohm.
3. Make sure the reference plane under your RF traces and parts is not interrupted.
4. Use bended tracks if possible (no hard corners).
5. Avoid stubs.
6. Make sure the self-resonance frequency of your impedance matching parts is as far as possible above 2,5Ghz.
7. If the design is small. Use a standard chip antenna as described in the reference designs (2450AT18A100E).
8. Make sure there is no reference plane under the chip antenna.

[Andreas]

Hi,

 

Although a bit larger than what you compare to, have you seen our nRF52840 Dongle? https://www.nordicsemi.com/Software-and-Tools/Development-Kits/nRF52840-Dongle

 

Best regards,

Andreas

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Hi Andreas,

Thanks for your reply. 

And Yes, I know about your dongle. In fact, I own a few of them.

I do like them and thy are great for firmware development. However, for my end customer its way to big. I really need a nice small dongle used in an office environment.

[Adrian Eggenberger]

Hi

We had the same discussion internally recently. The dongle from Nordic is a great option if its ok to have a PCB in you hands. For developping purpose it is fine but for customers?

 For customers we prefer dongles with a housing. We found the following usb dongles with an nRF52840 in it (I hope its allowed to name products from other companies):

1)          Raytac MDBT50Q-RX

2)          Fanstel USB840F

3)          Fanstel USB840M

Please note that the Fanstel dongles have no 32kHz crystal. You should also consider how you will initially program or update these dongles. As far as i know they all come with a bootloader preinstalled.

If anyone has more dongles I would be interessted to know.

Regards Adrian

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Thanks, I checked out the dongles. But they are still quite large.

I did find and buy some nRF52840 dongles from a Chinese company Holyiot (via Alibaba). But thy are also to big.

I did some design myself and even with the nRF52840 in a QFN73 enclosure its possible to create a dongle smaller than 20mm (like the Logitech dongle). And now with the WLCSP package this should be even easier to accomplish. So, I was hoping this small dongle was already on the marked.

The problem with building a small dongle our self is the mechanical tooling cost. And the volume needed by my customer is simply not large enough to cover for that cost.

[awneil]

Adrian Eggenberger said:

Fanstel USB840M

Ad said:

they are still quite large

The  Fanstel USB840M is 26 x 15 x 6 mm

So what is your maximum acceptable size?

Adrian Eggenberger said:

consider how you will initially program or update these dongles

at least one of the Fanstel ones has pads for a TagConnect ...