Headphone Charging Case - HDR175

Thread Starter

Ezachari

Joined Jan 30, 2021
3
For all those that enjoy helping newbies this is the post for you.

I am relocating my outdoor theater to our backyard using headphones now and ditching the big speakers. I have 8 sets of the Sennheiser HDR175 and want to rig up a way to charge them all while in a simple carrying case.

Can anyone assist on how to correctly wire/power such a device?

Charging Station: https://en-us.sennheiser.com/tr175
 

wayneh

Joined Sep 9, 2010
17,152
For all those that enjoy helping newbies this is the post for you.

I am relocating my outdoor theater to our backyard using headphones now and ditching the big speakers. I have 8 sets of the Sennheiser HDR175 and want to rig up a way to charge them all while in a simple carrying case.

Can anyone assist on how to correctly wire/power such a device?

Charging Station: https://en-us.sennheiser.com/tr175
In my opinion, the best (easy, cheap, reliable) approach would be an off-the-shelf charger designed for lots of simultaneous AAA NiMH cells. Just take them out of the headphones to charge them.

If you don't care for that approach, the biggest challenge I see is mechanical, not electrical: getting a reliable connection to the built-in charging contacts on the headphones. Once you have that solved, you could probably still use off-the-shelf chargers. Yes, you could build your own charger with the appropriate electronics. There are dedicated ICs that properly charge various battery types, and you could build around one of those. But really there's no need in my opinion.
 

Thread Starter

Ezachari

Joined Jan 30, 2021
3
In my opinion, the best (easy, cheap, reliable) approach would be an off-the-shelf charger designed for lots of simultaneous AAA NiMH cells. Just take them out of the headphones to charge them.

If you don't care for that approach, the biggest challenge I see is mechanical, not electrical: getting a reliable connection to the built-in charging contacts on the headphones. Once you have that solved, you could probably still use off-the-shelf chargers. Yes, you could build your own charger with the appropriate electronics. There are dedicated ICs that properly charge various battery types, and you could build around one of those. But really there's no need in my opinion.
I would like to essentially “hang” them on a single rod that had multiple charging connections. Just like the top of the charging base. It there some type of off the wall system that can be modified to fit these needs?
It is all about conscience and ease of use. We want to be able to pickup a case that house all the headphones and a single base station. Wall it outside, plug it in and pull out the headsets for use. Then when finished, unplug and pack it back up, take it inside and then plug it into the wall for charging. It should also stop charging once the batteries are full.

I am just not familiar enough with these systems to design the electronic components. The case can easily be built at our shop once I know what electronics to design around. Thanks again for any additional help!
 

wayneh

Joined Sep 9, 2010
17,152
We want to be able to pickup a case that house all the headphones and a single base station. Wall it outside, plug it in and pull out the headsets for use.
Are you sure a single base unit will work with that many headphones? The manual says,
"Multi-receiver transmission – transmitter supports up to two pairs of headphones simultaneously"​
 

Thread Starter

Ezachari

Joined Jan 30, 2021
3
Are you sure a single base unit will work with that many headphones? The manual says,
"Multi-receiver transmission – transmitter supports up to two pairs of headphones simultaneously"​
Yes, the biggest problem to figure out is the charging.
 

wayneh

Joined Sep 9, 2010
17,152
Yes, the biggest problem to figure out is the charging.
Well, each headphone set will need its own battery charge controller system, suitable for 2 AAA NiMH cells.

It’s possible it manages each cell separately. The photo looks like a 3-pronged connector. I think you need to sort that part out first. Do you have a multimeter? A $10 one would be fine for checking voltages and current for this project.

Once you know what you need, you can either buy or build the charge controllers. You’ll also need a power supply rated high enough for the combined current. That’s not hard once you know what each charger needs. First things first.
 

Smelterer

Joined Jan 22, 2021
1
If you have the opportunity or access to a radio market, go there.
Often they sell homemade devices or something similar there. It might be easier to buy a more or less similar charger and just rebuild it. The voltages and amperages are about the same for similar devices, and it would be easier to re-flash the controller than to do everything from scratch.
 
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