uMiRF stuff - design question

Wireless & IoT
1

And and and…

uMiRF (Micro-mirf) has the second channel fully brought out! The uMiRF will have the .1" header footprint for the basic, single channel access but will have three pins off in the corner for access to the other channel.

We will also have addtional functionality. The original RF-24G unit simply tied the PWR_UP pin to VDD. This pin is essential for low power designs. We successfully controlled it on the WiTilt board to get our system below a 1.2mA avg current with a 10Hz dual axis tilt reading.

The new uMiRF ties the PWR_UP pin to VDD via a 100k resistor. It is also accessable via a throughhole pin - though not inline with the normal .1" minimal header.

Finally - we are hoping to test the uMiRF with a SMD footprint. That is, the uMiRF module should be able to be soldered directly to a PCB rather than using a bulk .1" header.

All of this is merely preview until we have the units built, in hand, tested, and ready to go. Pictures are definitely worth a thousand words. The Chinese labor day is delaying all PCBs for 6 days. We should have all parts in 10-14 days. We’ll let you know The front page is always where the latest parts are announced.

Which reminds me - I think we have 3 new items for today… Jeesh.

-Nathan

Thought it best to un-hijack another thread :slight_smile:

Looks pretty there, on that front page. I actually have a question about the design process. I’m considering a chip antenna over a PCB printed antenna, given my low rate production and lack of fancy test equipment. Was it easier to work with the chip antenna design? I’ve seen the Yageo antennas go for a bit under $5, so that’s worth a tradeoff of a square inch or so of PCB space if it can give me similar or better performance and easier implementation. and small size can’t hurt, either :slight_smile:

2

I didn’t lay the board out, but I might be able to answer. The microstrip antenna isn’t necessarily a guaranteed 50 ohms unless you’ve got a 3GHz network analyzer to check your work. The chip antenna is, and it’s hassle free. And it’s tiny! Nate’s got something for small things…

We did some range testing of the uber-Mirf (uMiRF) with the chip antenna yesterday. It was pretty impressive. We had reasonable 2-way out the door, down the hall, down the stairs, into the dining room…Was it as good as the BlueSmirf? Not sure, but it’s still pretty cool. I’m of the opinion that our matching network isn’t all it could be, but it’s just a hunch really. If I can just get Nate to cough up for that network analyzer.

Pete

3

Hey! :shock: So I like small RF devices! My own co-worker is picking on me… Jeesh!

4

Given your penchant for Mouser, you’re using either a one of two Yageo or a Panasonic antenna. I’ll have to look into that for my Zigbee stuff.

Pete, just build a network analyzer and charge the time/materials to Sparky :twisted:

I’m not looking for massive range, my RF’s only rated at 1mW or something. PAN first, SAN later. I’m still a mechanical engineer playing in too small a world for what he learned in college. Thanks for the info!

5

The linx technologies chip antennae for 2.4GHz stuff are about $1 each…

6

Yepa. The Yageo antennas are nearly $5 each… And larger.