SparkFun Forums

[RonnyM]

I am developing some short range UHF transceivers with the above Chipcon parts. They are extremely overvoltage sensitive, a pain to solder (QLP20), but loaded with features. Anyone worked with these? Any gotchas not spelled out in the data sheets?

Thanks
Ron

[samlittlewood]

I have been using cc2500 (same as cc1100, but at 2.4GHz) - no worries so far. I started with the nRF2401, but the RSSI info., fast frequency hopping, and being able trade data rate for sensitivity led me to the chipcon parts.

There are a bunch of settings you have to take from the chipcon supplied software, and the datasheet is pretty bloody reticent about how to lay out the RF side (other than 'do as we do'). Other than that, they have performed as advertised.

I have been toying with using the cc1100 instead, tempted by that reduced path loss, and quieter band.

http://www.sixthavenue.co.uk/files/flit ... sradio.jpg

TTFN

SamL

[RonnyM]

Nice boards! Is the one on the right the actual finished unit? What kind of range are you getting with varying data rates? What is the app?
The packet quality indicator has really helped me dial in the fastest speed at any given range. The code is still a bit raw though.
I am working at 915 MHz with a solid range of 100 meters LOS at 250Kbits/sec. If only there was a hardware level retransmit on packet failure. But short of that, it is an amazing chip.
I purchased the 2500 evaluation modules for future development, but haven't plugged them in quite yet. The water is fine at 900 though. 10 mW is somewhat low power for high speed and I'll have to push the output up a bit if it is to work at 500Kbits/sec.
Also found out my bench supply spikes much higher when being turned on and off. Lost four chips before scoping it! Very sensitive little gems. I'm spoiled with the indestructable PICs.

Ron

[samlittlewood]

Nice boards! Is the one on the right the actual finished unit? What kind of range are you getting with varying data rates? What is the app?

Yes - that is a finished item - the application is very lightweight indoor flying vehicles of various sorts. It has the radio, an MCU (C8051F316), 2 h bridges, 1 motor driver, and a voltage regulator. Pads for connecting another h bridge, 2 more motor drivers or telemetry inputs. They weigh less than 0.6 grams. More pics : Closeup and Development.

The other board is just the radio and RF section in a convenient format for breadboarding - ultimately, it will mount on a handset board that I am still laying out.

Range - very informally, 30 metres or so (IIRC, also, 250kbps), When I have a reasonably standalone setup, I will head for the park and do some better tests. I only really need ~10kbps to get the job done, so I hope to gain some range there.

If only there was a hardware level retransmit on packet failure.

Hmm - I don't do any retransmission at the moment - out of date control positions are not useful. If I was going to, for things like telemetry, then I would prefer to do it in software - in my case, the retransmission should take advantage of freq. hopping (to work around multipath fade).

However, I would image that application specific masked ROM versions of the MCU parts, (CC2510/1110) could be offered that implemented reliable streamed comms (eg: pretending to be a UART at each end) (USB? SPDIF?) - a bit like the FTDI parts.

Also found out my bench supply spikes much higher when being turned on and off.

I don't see a suitable 'Cringe' smiley - ouch! What is your application?

TTFN

SamL