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Discussion Starter #1
I have an XR650L (and hopefully soon a Wee/Vee) and have freqently had the frustration of not being able to talk to my wife, or the guy who's riding with us that day.

I have searched high and low, and cannot for the life of me find a simple solution that is practical and simple AND doesnt cost an arm and a leg.

Problem solved with just a little :headbang:

I am not really sure how to start this, as I am not installing it on my motorcyle(yet) as I am away from home for a while.

Oh goodness....here we go,

Parts list:
*NADY MRC11x Radio $69.99
http://www.newegg.com/Product/Product.aspx?Item=N82E16872125001&cm_re=nady-_-72-125-001-_-Product

*NADY MO-HEADSET $14.99 (for passenger, unit comes w/ 1 already)
http://www.newegg.com/Product/Product.aspx?Item=N82E16872125003&cm_re=nady-_-72-125-003-_-Product

* +5V Fixed-Voltage Regulator (7805A) $1.59
http://www.radioshack.com/product/index.jsp?productId=2062599

* TO-220 Mounting Hardware $1.99
http://www.radioshack.com/product/index.jsp?productId=2102859

* Small gauge wire roll (two pair inside one sheeth)
* Silicone caulking
* mount for radio
* couple misc. parts


w/


-Ok, the problem I saw with this setup (the MRC11x) is that it only operates on batteries (3xAAA) and has a 48hr standby-runtime. So for a trip, where one might be doing constant intercom/b2b it would drain the batteries rather fast. Also dependant on the batteries, is the power output (ie-range...)

-I looked for a charger for a while, and the only one that I could was a wall charger, the problem with that, is while charging the radio shuts down. -So much for constant power...

My solution was to let my inner USN electronics technician out, and rig it up.

First, I'll explain the theory...
According to the MRC11x data sheet:
Low Battery Display Threshold ........................................... 4.3-4.6VDC
Transmit Current (4.6VDC High Power) .............................. <0.8A (TX); <30mA (STBY); <100mA (RX)
Current Drain (Intercom) ..................................................... <100mA
Standby Current (4.6VDC) .................................................. <30mA
Power Required .................................................................. 4 Ni-Cad, NiMH or Alkaline AAA batteries (4.6-6.0 VDC)
Battery Life 4.6VDC (4xAAA) ............................................... >48 HR (RX)

The red lettering indicates the correct operating voltage requirements for the radio. (as well as the 'low voltage' threshold)

In order to provide power to the unit, we must 'mimic' the batteries, the only problem is that a motocycle is obviously not 4.6-6.0VDC. Luckily, for us, that is a simple fix, radioshack.com carries (most stores as well) a small model/hobby regulator called a 7805A, which accepts 0-35VDC and will regulate it down to +5 VDC up to 1A.
-Now we just need to know the requirements (mA) of the radio, well back to the handy spec sheet, we see this:
Low Battery Display Threshold ........................................... 4.3-4.6VDC
Transmit Current (4.6VDC High Power) .............................. <0.8A (TX); <30mA (STBY); <100mA (RX)
Current Drain (Intercom) ..................................................... <100mA
Standby Current (4.6VDC) .................................................. <30mA
Power Required .................................................................. 4 Ni-Cad, NiMH or Alkaline AAA batteries (4.6-6.0 VDC)
Battery Life 4.6VDC (4xAAA) ............................................... >48 HR (RX)





TADA! the amprage req can be met easily. for componet's safety sake, it would be wise to be able to disapate some heat as it would be running at 80% capacity. We shouldnt need much, so the above TO-220 Heatsink should do just the trick and still not be bulky.

-So with the theory done, how do we apply it?



With the above schematic you can see how we tied into vehicle power. you have the option here to make it ignition hot, or always hot, honestly, i personally would use ignition hot as it would more than likely prolong the lifespan of all the components (radio too)

with the wires hooked to the 7805A VR, both the incoming 12vdc, and the reg. 5vdc to the device, you should now be able to silicone the heatsink/reg inside of the battery compartment with the wire trailing out. Tuck the few wires inside the battery compartment in there, and pop the lid back on. I think the easiest route here is notch a small hole in the cover for the cable, and smear a drop of silicone on the inside to protect it from the weather (abap)
the 12vdc lead wires can be hooked where ever you would like, and the radio will remember its settings as it uses a rom chip to store the data entered. (ie. remembers your station settings and ect...) :thumbup:



sorry for the long post, i was trying to figure out how to power this, and it hit me out of nowhere how simple it really was :beatnik:

im going to sleep, this post wore me out!! :sleep: x11ty billion!
 

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Interesting....
Although having to buy two 70 dollar radios, 15 bucks each for headsets, and various other parts. doesn't seem that cost effective.
A Scala rider set wouldn't be much more money and is all set up.

Let us know how it works while riding.

Ken
 

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Interesting....
Although having to buy two 70 dollar radios, 15 bucks each for headsets, and various other parts. doesn't seem that cost effective.
A Scala rider set wouldn't be much more money and is all set up.

Let us know how it works while riding.

Ken
I agree. I'd just go with the Scala unit. Unless you like tinkering :mrgreen:

Also, using a 7805 to regulate down to 5V from 12-14VDC is very inefficient and you waste a lot of power, not to mention the regulator will get very hot. Not a good way to do this. Use a small switcher power supply instead, they are just a little bigger than a 7805. The exact model number eludes me at the moment but I can dig it up if you are interested.
 

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Discussion Starter #4
@maggot
requires only one radio for your motorcyle, your buddy would have to buy one to do bike2bike. it IS however compatable with anything that uses the FR spectrum.

@Arne
i was going for size, as the 7805a fits in the battery compartment. i was looking at another option, a different power regulator that you would have to mount somewhere else, and run the 5v feed to the bars (power several small devices as it was like 10A or something)

ultimatly i choose size, as 'a lot of power' is relative to the device/regulator. relative to the bike output, power loss is minimal i would think
 

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I love DIY and I love to hack things, so I understand you need (and problem).

That said, just bite the bullet and purchase an AutoCom or some other pricey, but well regarded comm system. I tried a few cheapies including one of two that I built and in the long run you will be happier (and maybe even spend less) with a "store" bought unit.

Either way, post up the solution and your comments. Good luck!

I have searched high and low, and cannot for the life of me find a simple solution that is practical and simple AND doesnt cost an arm and a leg.
Problem solved with just a little :headbang:
 

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Discussion Starter #6
yeah, i have a problem, its called take things apart and see whats inside...
even worse than that, i know perfectly enough to be dangerous!

autocom? how much do they run?
 

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Discussion Starter #8
sadly, i cannot access youtube from here, bandwidth restrictions :(

eventually i found it last night, but more inportantly i found a unit breakdown on a different site to show me the pros/cons.

looks nice, but dang, those are expensive. I have two bikes to outfit, so my costs double.
 

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Discussion Starter #9
I agree. I'd just go with the Scala unit. Unless you like tinkering :mrgreen:

Also, using a 7805 to regulate down to 5V from 12-14VDC is very inefficient and you waste a lot of power, not to mention the regulator will get very hot. Not a good way to do this. Use a small switcher power supply instead, they are just a little bigger than a 7805. The exact model number eludes me at the moment but I can dig it up if you are interested.
something more along these lines?

http://www.powerstream.com/dcdc.htm

or were you talking about componet level?

was the power loss 'a lot of power' in reference to componet level efficiency? i dont see how this could ever draw any serious amount from the vehicles charging system.
 

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Also, using a 7805 to regulate down to 5V from 12-14VDC is very inefficient and you waste a lot of power, not to mention the regulator will get very hot.
There may be better ways, but there is not a simpler way (IMO). I have built many many many 7805 rigs to get USB power from a bike or car. So far non have failed and I didn't heat sink any of them. The bigger 7805 package device seems pretty tuff.

Power use should be a non issue unless you plan to use it without the motor running for very long time periods.

That's just my experience.
 

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Discussion Starter #11
There may be better ways, but there is not a simpler way (IMO). I have built many many many 7805 rigs to get USB power from a bike or car. So far non have failed and I didn't heat sink any of them. The bigger 7805 package device seems pretty tuff.

Power use should be a non issue unless you plan to use it without the motor running for very long time periods.

That's just my experience.
The game plan, is that after i get back, i hook this up so when the ignition goes hot (turn the key) that the radio (and regulator) will also go hot. So there should be no issues with power drain on the battery as, even if it were transmitting all the time on high, 5V @ .80A is a VERY nominal draw on the electrical system.

just mho :mrgreen:
 

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The game plan, is that after i get back, i hook this up so when the ignition goes hot (turn the key) that the radio (and regulator) will also go hot. So there should be no issues with power drain on the battery as, even if it were transmitting all the time on high, 5V @ .80A is a VERY nominal draw on the electrical system.

just mho :mrgreen:
IMHO, I agree with your HO.
 

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Recommendations

Dualsport, First, thank you for your service!

Interesting project. Here are a few things to add to it. If you move the regulator outside of the bike you make the whole thing portable.

The load on the system is not an issue, but the peak load is an issue on a 7805. They are only rated for 0.5 A continuious(78M05), after that the junction temp rises enough to cause you issues. You definately need a heatsink given the environment its going into(by the way, that could be the frame of the bike). Preferably a boosted design if you do any significant transmitting(stuck VOX?). Improve the hardware your using - vibrations.

The other gottchas to look out for are the transients from the dynamic load and the EMI noise, both from the bike and the radio. Add good caps to the input and output and inductors on both the gnd and power to deal with this(be careful on the cap ESRs with 7805s, read the app notes). Digikey.com will be your friend by the time your done.

Voltar's right, stay away from switchers, too much work(& cost) for what it's worth. It introduces it's own set of issues, especially with the dynamic load you specified.

After looking at this you can see why some people would drop it and buy, but they don't have that need to tinker. Looking forward to seeing you safely home and hearing the results.
 

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Discussion Starter #15
good, HO unite :punk:

yeah, that was just the initial plans. i knew of the 7805 off the top of my head as i have used them in my jeep before for LEDs.

basically, the initial post was the chicken scratch :mod2_beta1:

i see the link you sent me to, for tha variable. i have see a couple, but was unsure (and didnt search TOO hard) on what resistors to put in place. on my home computer i have a program (LTSpice maybe?) that i could figure it out on. maybe i could get a small project enclosure from radio shack, then drop a couple of these LM317HV in to support a bit more amps. THEN, i could run some +5v feeds to the front to house a couple weathertight USB connectors, and rig the radio to plug into the power system via USB, for portability..?

:confused: ahh, its too cold here to think!


as for the :weapons_79:

my pleasure, i personally THANK YOU, for the support! :thumbup:
 

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Discussion Starter #16
as for the amperage, i wouldnt THINK it would be a problem, as the radio limits transmissions to 1.3 mins for internal protection (vox included)
also, during peak operation it would be under 80% load for 1.3 mins.

http://www.nady.com/manuals/motorcycle/mrc11X.pdf
specificly pg 18 (specs i referenced)

http://www.electrokits.com/Datasheets/7805-Datasheet
i wonder if i could come up with like a cordless phone battery that could be charged via the regulator, yet power the radio as well. kinda like an UPS, it would isolate the power? (electrical infer, ect.)
 

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Cheap intercom and bike to bike

I would not waste my time, you are just going to spin your wheels,

go to topgears website and one can purchase a Active plus unit with headsets for 140.00, add a motorola cord $20.00 and you will be in business. The system actually works and is designed for a bike. Bike power it and you are off to the races.

get a pair of motorola GMRS radios (59.00) with nicads and a charger, get the ones that have a mini usb charging port so you can charge them on the fly. this system would also allow one to integrate cell phone, music, and radar detector, and gps..................not too pricey either at least it can grow with you. Kieth

ps I am a autocom distributor but I am sending you to another vendor so we have no conflicts with the board. Kieth

remember penny wise pound foolish...........
 

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Discussion Starter #18
i have no qualms ordering a comm setup. i have heard almost nothing bad about the autocom, other than the price. the problem(s) i face, are outfitting it across multiple motorcycles. autocom would become very expensive for that, nor do i want to have to mess with re-packing it from bike to bike. i would prefer a 'mounted' semi perm setup, on both.

the other problem i have, is called tinkering. i can't help but use a solder gun.... :(
 

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I am contemplating an Autocom but haven't found the price that Keith mentioned for an Active plus with dual headsets..

To Due1Sport... I've read that many put it in a tank bag that's powered. Just move the bag from bike to bike??

I Think I'll start another thread on intercoms. :confused:

Ken
 

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Discussion Starter #20
I am contemplating an Autocom but haven't found the price that Keith mentioned for an Active plus with dual headsets..

To Due1Sport... I've read that many put it in a tank bag that's powered. Just move the bag from bike to bike??

I Think I'll start another thread on intercoms. :confused:

Ken
Ken,
yeah, i havent seen the autocoms for that price either. not saying they dont exist, as i havent searched that hard for one. -not someplace i can tinker on it yet.

this setup you could put whereever you want, within reach of the cables. i personally would be leary about placing it in a tankbag, not for power reasons, but if you will be doing much bike to bike, the ant will not have a clear LOS to the other ant
 
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