need help with 2.4Ghz NRF24L01

Wireless & IoT
1

(moderator: I apologize for having posted the below as a reply to someone elses post. Feel free to delete one)

I’d be very grateful if anyone has enough documentation or experience to help me understand if what i want to do is possible. For reference, at http://www.rentron.com/rf_remote_control.htm, the reynolds electronics website sells very simple lower freq. 433mhz transmitters and receivers, and their on the site they provide examples for 8 bit transmitters and receiver circuits. Clicking on them I was amazed. There are apparently two very simple chips made by Holtek, a HT640 and an HT648. The 640 is used to collect up to 18 bits of data (arbitrarily designated as 10 address and 8 data bits), which it then serializes, prepending some sync and timing bits, which it then just sends it into the transmitter with one wire. A single resistor sets the internal bit rate oscillator. Then on the receiving end, an HT648 chip is is used to do the opposite, recovering and synchronizing the serialized data and making it available on 18 individual pins, again arbitrarily designated 10 for address and 8 for data. The examples on that site are only using 8 of the available bits. This is exactly what I need! To be able to replicate some bits on a wireless link without having to deal with any MCU at all would spare me a lot of R & D time. Especially since I’d never need to recover my bits faster than a few dozen updates per second.

But I have one problem… the 433Mhz frequency modules in those examples both require antenna, and the application I have in mind has no room for such a clumsy addition. So I really had hoped for something similar in the 2.4Ghz band. Well e-bay is full of these nRFL24LO boards! But of course these are all China based suppliers and documentation is pretty limited, and most hints I’ve seen for usage around the net have all required some adruino based boards. Even if I did buy some canned Arduino board to get started, I fear this would bog me down in months of additional research. Especially having seen how simple these Holtek chips could make my life on a 433Mhz board, I just sense the a same could be done with these RF24LO boards with just a little help.

2

The Holtek chips are no longer available and have been replaced by what I believe to be a preprogrammed PIC processor (now sold by Rentron).

Take a look at the Wixel by Pololu. There is an already-programmed I/O repeater “app” that does exactly what you want. http://www.pololu.com/catalog/product/1339

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You’re right. those Holtek chips are in end of life now, and after examining them i see that they don’t work so well anyway. Something like a 200mS delay, and the decoders require a separate 8 bit latch to hold the data only when a “data valid” pin goes high. Those Wixel’s do seem impressive, but it seems like a pricey solution. I’ll give it a look, but having had some unpleasant surprises looking at performance details in some “I/O repeater” chip based solutions, I’d really like some info on the performance of this I/O repeater App before I spend this much.

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Post your questions on Pololu’s wixel forum, and you will probably be surprised at the quick response, and how helpful the engineers can be.