ANNOUNCE: the SqueezeAMP, next generation squeezeboxen amplifier/receiver

[Paul Webster]

Have you tried using your Echo to send to SqueezeAMP via Bluetooth?
If it works for you then I'll have another go.

Also - is there a way to stop neighbours connecting to the Bluetooth (e.g. to have a way to enable/disable new devices from pairing - while allowing registered devices to connect/disconnect)?
I ask because we recently heard a neighbour typing and I think it was because their Bluetooth headset had connected to a Bluetooth speaker in our place (not SqueezeAMP).

[frahe]

Lipo Balancing?

I really like this thing a lot and you've done a great job. I'm searching for diffenrent options to expand my system. Actually used a pi zero with justboom amp zero. But this thing here would be a much nicer mobile solution!
I would like to admit, that you should really revise the charging of the LiPo batteries! When I look at the pictures there is no connection for balancing the voltage of these. These batteries are really sensitive to overcharging and with three batteries in series you'll may easily get a too high voltage at one of the batteries. Just remember samsung handys a while ago... They had only bad cell quality, without overcharging. And you'll be using these players in your home, possibly standing on furniture. I'm coming from RC models and there you're charging your batteries with a balancer charger and in a special fire-proof bag... These cells may be a little bit more brittle like the ones used here and in RC you're charging at higher rates, but care should be taken when charging these cells!
Greetings,
Florian

[philippe_44]

ANNOUNCE: the SqueezeAMP, next generation squeezeboxen amplifier/receiver

I really like this thing a lot and you've done a great job. I'm searching for diffenrent options to expand my system. Actually used a pi zero with justboom amp zero. But this thing here would be a much nicer mobile solution!
I would like to admit, that you should really revise the charging of the LiPo batteries! When I look at the pictures there is no connection for balancing the voltage of these. These batteries are really sensitive to overcharging and with three batteries in series you'll may easily get a too high voltage at one of the batteries. Just remember samsung handys a while ago... They had only bad cell quality, without overcharging. And you'll be using these players in your home, possibly standing on furniture. I'm coming from RC models and there you're charging your batteries with a balancer charger and in a special fire-proof bag... These cells may be a little bit more brittle like the ones used here and in RC you're charging at higher rates, but care should be taken when charging these cells!
Greetings,
Florian

Hi Florian - Thanks.

Regarding charging, first there is no room for a charger with a cell balancer but although you are totally right that it’s a better solution, I disagree it’s mandatory in this case.

I’ve recommended only using packs with individual cell protection which is the case for all pre-assembled pack you find on the market, so that eliminates this risk.

Then, it’s a common practice to have such 2 or 3 cells in serie without a balancer and it’s part of the reference design of these chipset vendors.

There is a big big difference with RC: for RC use case, the charge / discharge rates are so high (10x C) that the cells will become unbalanced. Here, the rate are much lower (C or C/2) that the risk of unbalancing are very low.

I have made a pack for the Boom and a 3D printer attached case that makes it a permanent portable solution using the same principle and I’ve been running 5 of these these for more than 4 years now and I also have 3 telescopes using similar system and they are all running fine and have not shown any signification réduction in capacity.

Again, all packs have individual protection to avoid serious issues, so worst case you loose capacity.

Philippe

[philippe_44]

Have you tried using your Echo to send to SqueezeAMP via Bluetooth?
If it works for you then I'll have another go.

Also - is there a way to stop neighbours connecting to the Bluetooth (e.g. to have a way to enable/disable new devices from pairing - while allowing registered devices to connect/disconnect)?
I ask because we recently heard a neighbour typing and I think it was because their Bluetooth headset had connected to a Bluetooth speaker in our place (not SqueezeAMP).

I will try today to use my echo. Wrt blocking pairing, yes this can be fairly doable, at least to allow only one device. A list will be more complicated.

[sle118]

There is a big big difference with RC: for RC use case, the charge / discharge rates are so high (10x C) that the cells will become unbalanced.

I also do custom drones, and battery chemistry is different: LiPo vs Li-ion. LiPo is known to be unstable under specific conditions (which is like 90% of the time). SqueezeAmp should be assembled with Li-ion, the more stable type that's found everywhere these days.

As with Samsung's issue, I believe that most does were caused by batteries that did not fit Samsung's requirements for size; under charging/heat, their size became too large for the casing tolerances, causing ruptures in the battery wrapping.

[philippe_44]

I will try today to use my echo. Wrt blocking pairing, yes this can be fairly doable, at least to allow only one device. A list will be more complicated.

I tried with my Alexa, it worked

[Paul Webster]

I tried with my Alexa, it worked

I just tried again and still does not work for me.
When I pair the devices I see the green status LED on SqueezeAMP change from flashing (idle) to solid.
But when I ask Alexa to do something that should have a spoken response, I hear nothing.

I've done more research and found that this has been happening to a few people (since Sep 2019 or so) and was claimed by Amazon to be fixed in December 2019.

https://www.amazonforum.com/forums/devices/echo-alexa/524331-echo-alexa-does-not-change-volume-on-my-bluetooth

My Echo (Dot 2nd Generation) shows version number: 649649820
... which appears to be newer than Amazon lists on their firmware status page at

https://www.amazon.com/gp/help/customer/display.html?nodeId=GMB5FVUB6REAVTXY

which shows 649649720

[philippe_44]

I just tried again and still does not work for me.
When I pair the devices I see the green status LED on SqueezeAMP change from flashing (idle) to solid.
But when I ask Alexa to do something that should have a spoken response, I hear nothing.

I've done more research and found that this has been happening to a few people (since Sep 2019 or so) and was claimed by Amazon to be fixed in December 2019.

https://www.amazonforum.com/forums/devices/echo-alexa/524331-echo-alexa-does-not-change-volume-on-my-bluetooth

My Echo (Dot 2nd Generation) shows version number: 649649820
... which appears to be newer than Amazon lists on their firmware status page at

https://www.amazon.com/gp/help/customer/display.html?nodeId=GMB5FVUB6REAVTXY

which shows 649649720

Sound was pretty low for me as it was the combination of low Alexa volume and low LMS volume, so pushing both up did a difference. My echo is 1st Gen. I’ve made modifications that I’ve not published yet, but I don’t think this should impact you. Maybe make sure that LMS is stopped *not* paused - this has been fixed now but was not working correctly in the version you have

[Paul Webster]

Thanks - Pause v Stopped resolved it for me - in that I could hear Alexa speaking.

If Bluetooth (noise - not connection) had priority then I think I would use it even if it meant missing a few seconds of LMS playing something while the announcement came out.

[chill]

I’ve recommended only using packs with individual cell protection which is the case for all pre-assembled pack you find on the market, so that eliminates this risk.

I had a go at making my own 2x18500 pack. I used a couple of flat-top unprotected cells (these), and added a protection PCB (the 'Ver 3 7.4V 2A' PCB from here). The PCB protects against overcharging, full discharge, over-current and short circuit.

I don't have the tools to weld tabs onto these batteries, and I was a bit nervous about soldering directly to them, but with a hot soldering iron, a large flat solder tip, and a bit of flux it was fairly easy. I sleeved them with a bit of thick rubber heat shrink, to insulate the contacts and stabilise the whole assembly. They're a nice snug fit in the case. The cells have a nominal capacity of 2000mAh, and they last aaaaaages.

[philippe_44]

I had a go at making my own 2x18500 pack. I used a couple of flat-top unprotected cells (these), and added a protection PCB (the 'Ver 3 7.4V 2A' PCB from here). The PCB protects against overcharging, full discharge, over-current and short circuit.

I don't have the tools to weld tabs onto these batteries, and I was a bit nervous about soldering directly to them, but with a hot soldering iron, a large flat solder tip, and a bit of flux it was fairly easy. I sleeved them with a bit of thick rubber heat shrink, to insulate the contacts and stabilise the whole assembly. They're a nice snug fit in the case. The cells have a nominal capacity of 2000mAh, and they last aaaaaages.

Nice! Re soldering batteries, I've read that using acid core solder does the right chemical reaction for the steel/nickel-plated battery terminals. I bought such solder a while ago but not tried yet ... as I'm doing spot welding on my packs, but that reminded me that I need to try this solder reel I have. Will keep you posted

[Paul Webster]

I have SqueezeAMP directly connected to some passive ceiling speakers.
Sometimes the sound cuts out for a second or so but the green light on SqueezeAMP does not start flashing.

I have found that reducing the sound level stops the problem - so I assume that this is power related.

Do you think it is the speakers that are cutting out (some sort of built-in limiter) or is it SqueezeAMP itself (I suspect SqueezeAMP because both speakers cut out at the same time and return at the same time)?

If SqueezeAMP is changing the power supply the solution?
If yes - do you think I should increase the voltage or max amps ... or decrease?
The current supply is rated (but untested) as 12V 2A

[philippe_44]

I have SqueezeAMP directly connected to some passive ceiling speakers.
Sometimes the sound cuts out for a second or so but the green light on SqueezeAMP does not start flashing.

I have found that reducing the sound level stops the problem - so I assume that this is power related.

Do you think it is the speakers that are cutting out (some sort of built-in limiter) or is it SqueezeAMP itself (I suspect SqueezeAMP because both speakers cut out at the same time and return at the same time)?

If SqueezeAMP is changing the power supply the solution?
If yes - do you think I should increase the voltage or max amps ... or decrease?
The current supply is rated (but untested) as 12V 2A

Power supply seems fine, assuming it delivers - What about heat?

[frahe]

Hi Florian - Thanks.

Regarding charging, first there is no room for a charger with a cell balancer but although you are totally right that it’s a better solution, I disagree it’s mandatory in this case.

I’ve recommended only using packs with individual cell protection which is the case for all pre-assembled pack you find on the market, so that eliminates this risk.

Then, it’s a common practice to have such 2 or 3 cells in serie without a balancer and it’s part of the reference design of these chipset vendors.

There is a big big difference with RC: for RC use case, the charge / discharge rates are so high (10x C) that the cells will become unbalanced. Here, the rate are much lower (C or C/2) that the risk of unbalancing are very low.

I have made a pack for the Boom and a 3D printer attached case that makes it a permanent portable solution using the same principle and I’ve been running 5 of these these for more than 4 years now and I also have 3 telescopes using similar system and they are all running fine and have not shown any signification réduction in capacity.

Again, all packs have individual protection to avoid serious issues, so worst case you loose capacity.

Philippe

Thank you Philippe,
for the detailed answer and all other for the discussion. I learned from your posts. I didn't have in mind that these cells are also produced with protection circuits. And yes in this case everything is fine, you won't need a balancing, since these cells will do it by themselves. Especially since you're charging with lower currents. Would be nice to have a notice on the github repository, that one should use cells with inbuilt protection circuits. I suppose there will be more people like me not aware of that.
Greetings,
Florian

[Paul Webster]

Power supply seems fine, assuming it delivers - What about heat?

I'll try orienting it a different way (it is on a shelf with very little free airflow so could be that).