Can I increase the range? IR and RF

[Stiganator]

Nikon D70, D50, D40 remote

If I dropped in say a 10 ohm resistor into that puppy and assuming that little battery is like 3.3 volts should that increase the LED output giving me more range for the remote?

Do you know of any small RF units i could connect this to so I wouldn't need line of sight.

I could make a bracket that sat between the camera and the tripod that would hold the IR unit that would be activated by the RF unit that way I wouldn't have to see myself pointing to the camera with the IR remote and I could theoretically get greater range. What kind of range do you think I could get with a compact RF setup?

 

[CTho9305]

Make sure you don't exceed the rated current of the LED.

 

[PottedMeat]

The maximum current that can be sourced/sunk by that GPIO pin is 25mA - I dont know the forward voltage of that IR LED but he listed 33-220Ohms for the resistor so he probably took that into account. You may be able to just supply the thing with another CR2032 battery in series for a total of 6V then drive a npn transistor with that GPIO pin. Have a IR LED attached to the collector with a resistor and you may be able to drive the LED with around 30-40mA.

 

[bobsmith1492]

Replace the transmitter with a laser diode driven by a transistor. I send AM audio probably 100 yards in my back yard using a cheap old laser pen. The only problem may be if the phototransistor at the receiver doesn't respond well to the laser light, but you'll never know unless you try.

 

[par0dox99]

Depending on how far you want to take this, I would design an rf link using the nordic chip.
I have had great success with these rf modules in burst packet mode. 300 meters plus in open fields, through walls at closer range.

http://www.sparkfun.com/commerce/product_info.php?products_id=151

sparkfun even has some sample pic code to get you started.
They also have some smaller versions of the nordic chip but you loose range quickly.

 

[Stiganator]

Do you think I could extend the range on that Nordic chip? 1MB@150 meters, 250K@280 meters, I really only need so send a single signal. So maybe like 1 byte? does that mean I could get it up to say 500 meters?

 

[Stiganator]

That site is awesome btw.

 

[par0dox99]

I know right, sparkfun my proverbial candy store.

These things have a CRC built in (Cyclic redundancy check), if it fails it will dump the packet and you will never know it. You can turn it off so you might be able to extend the range using the minimum payloads on everything and minimizing the total packet length, but how much I'm not sure. 500 m might be reaching but I've never tried it. The only problem with going without a CRC is that the data fields could be corrupt at large distances.


Another i've been wanting to play with but haven't yet are these.
http://www.maxstream.net/products/xbee/xbee-pro-oem-rf-module-zigbee.php
This is claiming a 1 mile line of sight range. About the same as the size as the nordic, just much more sophisticated

 

[Mark R]

I'd do it the brute force and ignorance way.

Replace the LED in the remote with an N-MOSFET in open-drain configuration. Use it to drive a bank of high-power IR emitter LEDs.

Optionally, use some collimating optics to form a near-parallel beam. I've seen this done in a simple 'video sender' by placing a single IR emitter at the focus of a simple fresnel lens - this setup could send a video signal 100 feet.

 

[Stiganator]

The downside to using an array of IR is you still need to have LOS. In fact you also have to be on the left side of the photo to hit the sensor since the lens would block it form the right. RF would be ideal because you could be anywhere and activate it from a pocket or what have you.

 

[slackwarelinux]

Another interesting route other than IR or RF might be ultrasonic. I don't know much about the potential range of ultrasonic switches though.

Originally posted by: par0dox99
I know right, sparkfun my proverbial candy store.
Another i've been wanting to play with but haven't yet are these.
http://www.maxstream.net/products/xbee/xbee-pro-oem-rf-module-zigbee.php
This is claiming a 1 mile line of sight range. About the same as the size as the nordic, just much more sophisticated

I've got a pair of the Xbee Pro modules, and they work great. I have not tested them to a mile, but they easily work across my house. They are a bit of a pain to interface with microcontrollers because they use 3.3 volt signaling.

I don't think these would be a very economical solution for a single command remote though, the Xbee Pros cost 32$ each, compared to a less than one dollar IR LED. The circuit would also require a more complicated regulated power supply, and possibly a bigger battery. Anyways, the Xbee modules are really great though.

 

[Stiganator]

with the Xbee Pro do you have to buy two of them or do they come as a set receiver and transmitter? I think the nordic came with both.

 

[par0dox99]

Originally posted by: Stiganator
with the Xbee Pro do you have to buy two of them or do they come as a set receiver and transmitter? I think the nordic came with both.

Unfortunately, you have to by two units to complete an RF link in both cases. The link I sent you for sparkfun, shows two units in the picture but if you scroll down the page at the bottom right above the "add to cart" you will see a disclaimer stating, "Sold by single units."
You'll have to design two transceivers with two microcontrollers.

 

[par0dox99]

Originally posted by: slackwarelinux
Another interesting route other than IR or RF might be ultrasonic. I don't know much about the potential range of ultrasonic switches though.

Originally posted by: par0dox99
I know right, sparkfun my proverbial candy store.
Another i've been wanting to play with but haven't yet are these.
http://www.maxstream.net/products/xbee/xbee-pro-oem-rf-module-zigbee.php
This is claiming a 1 mile line of sight range. About the same as the size as the nordic, just much more sophisticated

I've got a pair of the Xbee Pro modules, and they work great. I have not tested them to a mile, but they easily work across my house. They are a bit of a pain to interface with microcontrollers because they use 3.3 volt signaling.

I don't think these would be a very economical solution for a single command remote though, the Xbee Pros cost 32$ each, compared to a less than one dollar IR LED. The circuit would also require a more complicated regulated power supply, and possibly a bigger battery. Anyways, the Xbee modules are really great though.

The Nordic is 3 volts as well. You should check out TI's MSP430 family, great low power controller.