Best short distance wireless solution - Electronic Circuits Projects Diagrams Free

cvrider · 15th April 2008, 04:22 AM

I am looking to create a wireless solution with a very small footprint. I want to create 2 wireless transmitters that send to a single receiver. The distance is probably 3 feet or less and I need to transfer maybe a couple bytes of data 2 times a second about. The transmitters need to be as small as possible (quarter sized if possible).

I was looking at some basic transmitters which seem to maybe work:

http://www.rentron.com/Linx/TXM-433-LR.htm

http://www.rentron.com/remote_control/TWS-434-6.htm

I could use a PIC BS1-IC on each transmitter to manupulate data before being sent. However, because there are 2 transmitters, I am worried about noise etc. I then looked at a possible bluetooth solution, but I don't see anything promising besides maybe a Broadcom bluetooth chip which seems to be more for manufacturing than home circuits:

http://www.broadcom.com/products/Blu...utions/BCM2042

The bluetooth however would take care of frequency issues with multiple transmitters.

Does anyone have any ideas on rf products that may meet this requirement? The closest comparison I can think of to what I want to do is similar to a wireless bicycle computer (same distance and transmitter size). However, I don't think those computers send anything complicated over the wireless link.

**3v0** · 15th April 2008, 10:30 AM

At times we get posts such as yours where people post about what they want to do using a description that attempts to hid the actual application. More often then not we provide solutions that do not work for the OP because the original description was too vague. It is much better to describe the application.

This solution requires a 2nd receiver.
Use two transmitters on the same frequency. Equip one with a receiver. The receiver equipped transmitter listens to the other and will only transmit after the non receiver transmitter has finished.

cvrider · 15th April 2008, 07:56 PM

In my application, I want to have two wireless devices attached to each pedal on a stationary bike sending data about my pedal stroke. The data will be sent to a microcontroller with a receiver module and print out some data for me on an lcd. I just want to know the best way to accomplish this. I want the transmitters to be very low power and they really only need to send a few feet. Also, since there will be two transmitters, how can I handle that?

**Nigel Goodwin** · 15th April 2008, 08:20 PM

How are you measuring the power independently on each pedal?.

blueroomelectronics · 15th April 2008, 08:21 PM

What sort of sensors are attached to the petals?

cvrider · 15th April 2008, 09:03 PM

a strain gauge or accelerometer. I'm not sure yet what raw output the pedal device will send. It will most likely be a voltage or resistance value that needs to be sent over rf. It's very possible I will need to send multiple voltage and resistance values if there are multiple sensors on a single pedal. However, I do not want the two pedals on the bike to interfere with one another.

**Nigel Goodwin** · 16th April 2008, 10:24 AM

Use one transmitter and send information from both pedals through it.

To connect them together, drill a hole through the centre of the axle the pedals are on, and feed the wire through - you may need to get someone with a lathe to do this.

But I would have thought you could easily measure the output power from what it's feeding, and individual pedal power by detecting each pedal down stroke.

**3v0** · 16th April 2008, 10:48 AM

There are often several ways to do the same thing.

If there is a clear path from the bottom of the pedals to the base of the bike you could use IR communication. Each side could have its own xmiter and receiver.

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15th April 2008, 04:22 AM	(permalink)
cvrider	Best short distance wireless solution I am looking to create a wireless solution with a very small footprint. I want to create 2 wireless transmitters that send to a single receiver. The distance is probably 3 feet or less and I need to transfer maybe a couple bytes of data 2 times a second about. The transmitters need to be as small as possible (quarter sized if possible). I was looking at some basic transmitters which seem to maybe work: http://www.rentron.com/Linx/TXM-433-LR.htm http://www.rentron.com/remote_control/TWS-434-6.htm I could use a PIC BS1-IC on each transmitter to manupulate data before being sent. However, because there are 2 transmitters, I am worried about noise etc. I then looked at a possible bluetooth solution, but I don't see anything promising besides maybe a Broadcom bluetooth chip which seems to be more for manufacturing than home circuits: http://www.broadcom.com/products/Blu...utions/BCM2042 The bluetooth however would take care of frequency issues with multiple transmitters. Does anyone have any ideas on rf products that may meet this requirement? The closest comparison I can think of to what I want to do is similar to a wireless bicycle computer (same distance and transmitter size). However, I don't think those computers send anything complicated over the wireless link.

15th April 2008, 10:30 AM	(permalink)
3v0	At times we get posts such as yours where people post about what they want to do using a description that attempts to hid the actual application. More often then not we provide solutions that do not work for the OP because the original description was too vague. It is much better to describe the application. This solution requires a 2nd receiver. Use two transmitters on the same frequency. Equip one with a receiver. The receiver equipped transmitter listens to the other and will only transmit after the non receiver transmitter has finished. __________________ search engine for electronic parts Junebug USB PIC programmer kit., USB Bit Wacker, 3v0's Homepage The 15 Minute Printed Circuit Board! (+drill time)

15th April 2008, 07:56 PM	(permalink)
cvrider	In my application, I want to have two wireless devices attached to each pedal on a stationary bike sending data about my pedal stroke. The data will be sent to a microcontroller with a receiver module and print out some data for me on an lcd. I just want to know the best way to accomplish this. I want the transmitters to be very low power and they really only need to send a few feet. Also, since there will be two transmitters, how can I handle that?

15th April 2008, 08:20 PM	(permalink)
Nigel Goodwin	How are you measuring the power independently on each pedal?. __________________ PIC programmer software, and PIC Tutorials at: http://www.winpicprog.co.uk

15th April 2008, 08:21 PM	(permalink)
blueroomelectronics	What sort of sensors are attached to the petals? __________________ Bill Smart Kits build Smart People http://www.blueroomelectronics.com

15th April 2008, 09:03 PM	(permalink)
cvrider	a strain gauge or accelerometer. I'm not sure yet what raw output the pedal device will send. It will most likely be a voltage or resistance value that needs to be sent over rf. It's very possible I will need to send multiple voltage and resistance values if there are multiple sensors on a single pedal. However, I do not want the two pedals on the bike to interfere with one another.

16th April 2008, 10:24 AM	(permalink)
Nigel Goodwin	Use one transmitter and send information from both pedals through it. To connect them together, drill a hole through the centre of the axle the pedals are on, and feed the wire through - you may need to get someone with a lathe to do this. But I would have thought you could easily measure the output power from what it's feeding, and individual pedal power by detecting each pedal down stroke. __________________ PIC programmer software, and PIC Tutorials at: http://www.winpicprog.co.uk

16th April 2008, 10:48 AM	(permalink)
3v0	There are often several ways to do the same thing. If there is a clear path from the bottom of the pedals to the base of the bike you could use IR communication. Each side could have its own xmiter and receiver. __________________ search engine for electronic parts Junebug USB PIC programmer kit., USB Bit Wacker, 3v0's Homepage The 15 Minute Printed Circuit Board! (+drill time)