Sena SR10, AUX power ON/OFF trigger not working (solved)

ST1100Y

ST1100Y

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Got my GF that SR10 on her NT700VA to enable a 2-way with her SMH5... headset pairing, PTT, etc... all working fine as expected, latest firmware installed, all smooth... :thumb:

What for the life of will not work, is the SR10 turning OFF when the ignition switched 5V goes out, and to turn back ON when the 5V gets live again... :confused:

Box and literature claim "12V bike ignition on/off control"... :shrug2:

Once 5V are applied only the red LED lights solid, indicating [charging], so you've to turn the kit ON manually... solid blue & solid red, all working...

With 5V OFF both blue & red LEDs just remain ON... till the darn battery runs empty...

Any key combination I've overlooked there?

Hint: I used a quality inline 12V-5V micro USB power supply instead of the supplied cigarette lighter plug...
 
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ST1100Y said:
Box and literature claim "12V bike ignition on/off control"... :shrug2:

Once 5V are applied only the red LED lights solid, indicating [charging], so you've to turn the kit ON manually... solid blue & solid red, all working...

With 5V OFF both blue & red LEDs just remain ON... till the darn battery runs empty...
Click to expand...
Have you tried disconnecting one thing at a time, to see what will turn off the LEDs?

Is it possible the LEDs are staying on just because of a power-supply capacitor, etc?
 
I run my SR-10 on battery only. I guess you could charge it at lunch, but I have never had a problem with it lasting all day. The only problem I have is getting a reliable connection with Cardo PackTalk Bold. I guess I'll be switching to Sena this spring.
 
You need to use the supplied 12V plug to make the unit turn on/off automatically with the bike's power. It will not work with a USB cable.
 
Bust-A-Nut said:
You need to use the supplied 12V plug to make the unit turn on/off automatically with the bike's power. It will not work with a USB cable.
Click to expand...
It's not "a USB cable"... its a designated, stabilized, fully electronic 12V - 5V voltage converter/power supply... (had a look that crude design in the delivered thingy?!)...

Will have another go on this during the weekend...
 
First shown the "voltage converter" supplied by SENA

As said, a very crude design, at least I would have used a linear reg IC...

SENA cig adapter.jpg


But this label could be an indication that there is some flag or bridge inside the micro-USB plug...

SENA cig adapter label.jpg

Will test tomorrow...
 
That is not a standard USB supply. There is no voltage regulator; only four diodes in series, each of which has a forward drop of 0.6v.

The output with 12 volts in is (12 - (4 x 0.6)) 9.6 volts; more with more in. That's why they warn you to not use it on other devices.
 
Larry Fine said:
There is no voltage regulator; only four diodes in series, each of which has a forward drop of 0.6v.
Click to expand...
My sentiments exactly... considering the onboard voltage these days being close to 13V, the SENA (or any) 5V device will soon be cooked...
An LM7805 with a 10mF on each side would be the minimum setup IMHO...
 
A trick that is used with the SM-10, which is a cousin to the SR-10, is to open the case and unplug the battery. This forces the unit to power off and on with the power supply. Not sure if this will work on the SR-10, but thought I would share.
 
Larry Fine said:
The output with 12 volts in is (12 - (4 x 0.6)) 9.6 volts; more with more in.
Click to expand...
Optimistic numbers... ;)
At a purchase price of € 199,- my basic electronic knowledge is pretty disappointed about such a flimsy "PRC circuitry"; I mean we talk fractions of a cent on component/MFG value... :confused:
Ran measurements today: battery @ 12,5V, output of SENA thingy: 10,74V !! :scared2:
Still ran a bench-test with that cig plug (amazed that it didn't blow the internal battery... :rolleyes: ), and the SR10 did respond with proper ON/OFF behavior... if that's due a "flag" inside the USB plug, or by the massive voltage it gets shoved in, is yet not determined...
 
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mlheck said:
A trick that is used with the SM-10, which is a cousin to the SR-10, is to open the case and unplug the battery. This forces the unit to power off and on with the power supply.
Click to expand...
Good tip and, if it works, a simple fix worth a try; with the slight risk that the unit "forgets" the BT pairing though...
 
mlheck said:
A trick that is used with the SM-10, which is a cousin to the SR-10, is to open the case and unplug the battery. This forces the unit to power off and on with the power supply. Not sure if this will work on the SR-10, but thought I would share.
Click to expand...
This trick does not work on the SR-10. I have a SR-10 and did try this. Using the 12v cigarette adapter does work if the adapter is on a switched power.
 
ST1100Y said:
As tested today, but the output of >10V is WAY too high...
Click to expand...
So you now work for Sena and know their power supply is providing too much voltage. I tend to trust the manufacturer to supply the correct equipment to power their product.

The picture is from the included 12v cigarette adapter.
 

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A weird concept, not mentioned anywhere in the literature... :mad:
The SR-10 obviously detects if there 5V or 12V present at the USB line and changes to [charge] or [ON/OFF]...
The 4 zener diodes simply serve some form of "protection" from the +14V you see in a running vehicle system... :confused:
Will have to work with that as temp solution for now, but I'll instantly break out the soldering iron once the shops have normal operations again to build a proper circuit...
 

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Found those (8 PCBs for a tenner... ;))

IMG_20200425_093315.jpg

Testing @ ~14V input...

IMG_20200425_083928.jpg

... getting a fully stable 12V output, now that I like :cool:

IMG_20200425_083908.jpg

Wrapped and secured in shrink-tube, installed in the NT, all working as supposed... :cool:
 
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Alright, Bluetooth auto re-pairing works too... <phew!> o_O
Always the unknown frontiers with those modern gadgets, wasn't convinced that the SR10 will memorize the headset...

But the Kenwood is also ripe to receive one of those neat buck step-down PCBs as solid power supply, since the genuine battery eliminator showing some intermittence...
 
Well, after I upgraded the power module for the Kenwood radio, we still had some issues

- she receiving me pretty much flawless
- I'm OTOH getting high pitch buzz from her radio, with her audio only very faint in the background...

Almost giving up on this setup I gave it one last twitch by installing a noise-filter into the power supply... and...

Eureka, it finally works! :cool:
The NT seems to have a pretty dirty and noisy onboard voltage... (so much about "newer is better"...)
A bit over a mile within rural(!) area, is quite a good range for those analog PMRs and serves the purpose.
 
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