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Author Topic: Small Receiver  (Read 681 times)

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Offline sherbyTopic starter

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Small Receiver
« on: June 14, 2013, 02:35:55 AM »
Hey Guys, i was building a project where i require to give a signal to a robot wirelessly. The Robot is of very small size.
I need the receiver to be very small,the signal could be digital, as only 1 actuator need to be activated on a signal from transmitter.

The Size of transmitter doesnt matter, but i was looking for the smallest receiver possible.
Is there something you guys would know of, that could help me on this.

There is one at Sparkfun,
https://www.sparkfun.com/products/10534
the receiver is the same size, however i was looking for something much smaller.
Any suggestion will be appreciated.

Thank You

Offline jwatte

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Re: Small Receiver
« Reply #1 on: June 14, 2013, 10:17:05 AM »
That Sparkfun module looks like it's only about 10 mm x 14 mm or so. You need smaller?

Perhaps see if you can find a FM Radio receiver chip in surface mount size? It may either be possible to change this to receive on an open-ish band, or tune it down below 88 MHz and keep the power so small that nobody will notice/mind for a hobby project (might or might not be technically legal in your locale.)

The Si4313 is available in 20-VQFN: http://www.digikey.com/product-detail/en/SI4313-B1-FM/336-1980-5-ND/2340775 but it needs support circuitry

The Alpha modules are kind-of small, but probably no smaller than the Sparkfun ones: http://www.digikey.com/product-detail/en/ALPHA-RX915S/ALPHA-RX915S-ND/2000721 (note: the pin spacing is much tighter than 100 mil)

In the end, a super-dumb AM receiver is just a tuned filter, which you may be able to build in a very small form factor using the smallest available components, but it's unlikely to be a simple project, working at RF frequencies...

Offline johnwarfin

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Re: Small Receiver
« Reply #2 on: June 14, 2013, 03:42:13 PM »
simplest solution is a tiny low cost rc rx. small flysky units can be had for around $10 and the radio controller aint much more. for really small theres 200 milligram diy versions. google is your friend.

Offline jwatte

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Re: Small Receiver
« Reply #3 on: June 14, 2013, 05:19:01 PM »
All the micro receivers I can find are bigger than the Sparkfun one posted in the original request.
Do you have links to smaller ones? That would be useful.

Offline fester225

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Re: Small Receiver
« Reply #4 on: June 15, 2013, 05:45:44 PM »
If you only need 1 channel, could you use light?
"There is only one basic human right, the right to do as you damn well please. And with it comes the only basic human duty, the duty to take the consequences." -- PJ O'Rourke

Offline johnwarfin

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Re: Small Receiver
« Reply #5 on: June 15, 2013, 08:16:53 PM »
All the micro receivers I can find are bigger than the Sparkfun one posted in the original request.
Do you have links to smaller ones? That would be useful.


flysky is the most common chinese protocol and there are radios available ranging from $14 4ch to top of the line 16ch with most advanced features at any price. heres a diy flysky rx that weighs 190milligrams and isnt much bigger than grain of rice and costs less than $4 to make:

http://www.rcgroups.com/forums/showthread.php?t=1798913

theres also commercial versions from companies like frsky and dreamsky that weigh in less than a gram when stripped. in fact the most common brand protocol is spektrum and orange and lemon versions weigh  little more than a gram or two and cost about $5. if you have trouble searching these off the shelf ones let me know and i will get you more links.


Offline johnwarfin

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Re: Small Receiver
« Reply #6 on: June 15, 2013, 08:28:18 PM »
i should also mention the sparkfun ook device linked is the tx which op mentioned was not size constrained. the rx is much bigger. and niether are functional out of the box. little more than uhf front ends really. as mentioned a computer is required at each end to decode any control signals.

the rc units are smaller, cheaper, and ready go regarding control of servos, lights, or motors.

Offline jwatte

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Re: Small Receiver
« Reply #7 on: June 15, 2013, 08:35:14 PM »
Ah! You dead bug solder a chip, and can get down in size. None of the commercial units I found were anywhere near as small, and all of the "packaged" units in that thread have a much bigger PCB.

Here's the "how to go small" picture, for reference:
http://static.rcgroups.net/forums/attachments/2/3/3/4/3/1/t5456482-159-thumb-IMG_1505.jpg?d=1358449727


Regarding using light: Yes, you can use light, if you can figure out a good way to tell an intentional signal apart from ambient light changes. A tuned laser sender and narrowband infrared sensor might be one way to try it. Using a specific modulation frequency (like IR remote controls use 38 kHz) would be another.

Offline johnwarfin

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Re: Small Receiver
« Reply #8 on: June 16, 2013, 11:45:59 AM »
Ah! You dead bug solder a chip, and can get down in size. None of the commercial units I found were anywhere near as small,


then i highly recommend checking out dave theunissons commercial products:

http://www.micronradiocontrol.co.uk/rx_dt.html

there are other similar sub-nano rx available from similar companies but his are most popular. having had considerble experience with those ook units i assure you, even before attaching controllers to make them work, they are much bigger. basically legacy designs from early car/garage keyfobs and have been replaced with modern 2.4ghz transceiver modules which are cheaper and outperform.

in any case imo off-the-shelf rc rx is by far the cheapest and easiest path for wireless control. bare rf modules and ir circuits can be made to work but require considerable expertise and experience.

Offline jwatte

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Re: Small Receiver
« Reply #9 on: June 16, 2013, 12:04:15 PM »
Wow, that Rx31 is pretty small! Thanks for the link!


 


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