SparkFun Forums

[MJ]

In reading the Nordic Semiconductor nRF2401 datasheet, it says it only needs two external components--a resistor and a crystal. However, their example in the sheet has many more. Despite my tinkering with electronics, all those tiny pieces intimidate me!

Aside from buying the fully assembled version that Laipac made (I actually already have two), is it actually feasible to build an RF module with just the nRF2401 chip and two components, or is it necessary to have the full BOM they spec out?

Thanks,
Jeff

[pittuck]

Why yes, spark fun have wireless accellerometers and the smirf modules, why dont u email them directly for info. (Sparky is a busy person and although his help on the forum is very helpfull he cant be here all the time! email is the fastest way, perhaps even post back with da answers!)

[MJ]

Will do; I agree that Sparky's help is excellent, esp considering he's running the business as well.

I'll try and contact Nordic directly and let you if I hear back.

[MJ]

I contacted Nordic and included their response, masking the respondent's name.

Dear Mr. Hoffman,

I am xxxxxxxxxx, an Application Engineer at the Wireless Communication
Unit at Nordic Semiconductor ASA.

> In reading through the press releases and documentation for the nRF2401, I see
> that it's possible to design a complete RF solution with only two external
> components to the nRF2401--a resistor and crystal.

Well, these are sales arguments made by marketing people, so..........

But, as a technical guy I will tell you the whole truth.

The needed external components are what you see in the application schematic in Figure 21 on page 35 in the nRF2401 datasheet. If we look at what is basically needed to make the nRF2401 device functional, you need the bias resistor R2 and the reference crystal X1. But in a real world application you will need power supply de-coupling and matching circuitry towards the antenna. If a single ended (un-balanced) 50 ohm antenna is used, then all the components shown in the Figure 21 are needed. If some kind of a differential (balanced) antenna is used (like e.g. a differential folded half wavelength dipole), then you could omit matching network components L1-L4 and C8-C11.

Best Regards,
xxxxxxx
M.Sc.E.E.
Application Engineer
Wireless Communication
Nordic Semiconductor ASA

[sparky]

pittuck - I love you - We're running around here with our heads cut off. I keep falling behind with the forum.

MJ - I hadn't heard the two component claim, but it makes sense with the answer from the tech. I love it when marketing gets ahold of things and how they manage to twist things around.

The added components are just that - decoupling and impendance matching for the 50ohm antenna.

We build all our own units but it has taken quite a bit of experience, time, and blown boards. You can build your own, but you need some good schematics, footprints, and a steady soldering hand. Usually, the cost of time far outweighs the cost of buying units off the shelf.

-Nathan

[pittuck]

Well i have just soldered a handful of 0603's and some SO3 mosfets + a 16F688 with no probs! kinda easy really....

Anyhow, i am using a tRF-24G units and the pic to make a i2c interface to a ready made network. U might say its kinda useless to a hardcore progammer or the experimenter who want to play wireless. but there is a big following of picaxe and basic stamp where accessing a i2c wireless transicver will take only 1 or 2 lines of code!