Bluetooth 'Zephyr'

[PeterJ]

Has anyone come across this Bluetooth module included with this +2 before? I can't find any details on the internet.

https://www.ebay.co.uk/itm/394083963532

I have Bluetooth on my ZX Spectrum Clone - ZX Sizif-512 and it works flawlessly.

[Tiger]

It's a little bit strange because there is nothing to see about a "pairing method" on the pictures. If it is build within the Spectrum there must be anything to see how you can pair Bluetooth devices. So I think it is a simple Bluetooth to Audio module (ESP32 or anything like this) but it is not described in the offer .. Why don't take an app like "ZX Tape Player" or "PlayZX" to transfer Spectrum files via smartphone to the Speccy ear-input?
A link to Zephyr is here: https://docs.zephyrproject.org/latest/s ... tooth.html
It seems to work with Bluetooth-dongles like this
https://www.snapdeal.com/product/zephyr ... 0408865321

[PeterJ]

Hi @Tiger,

Thanks for that. I've had very mixed results with the audio lead method, but using the same apps as you mention on my Android device via Bluetooth just seems to work perfectly every time.

[Nitrowing]

Lots of basic Bluetooth modules pair with '0000' - my OBDII modules, my audio receivers...

[zx64]

I have Bluetooth on my ZX Spectrum Clone - ZX Sizif-512 and it works flawlessly.

Which module do you have in sizif?

[PeterJ]

Hi @zx64,

Apologies for the delay. It's one of these:

https://www.aliexpress.com/item/4001152611701.html

MH-MX8

[Pobulous]

How well does it work with the more finicky speedloaders?
Quite a neat (and cheap!) solution if it works well.

I would be interested to know where they wired it in.

[PeterJ]

Hi @Pobulous,

I'm happy to test any games. Just PM me a list.

[oO cozy Oo]

I`ve been looking to add a bluetooth module to an old spare zx spectrum , which is the best place to get a safe 5v point from and ground, also left and right which part of the audio pionts do i solder ?



Cheers

[KWF]

MH-M18 modules got weak audio outputs, the signal swing is approx. 1V only and you need an amplifier.
Have look here: https://forum.tlienhard.com/phpBB3/viewtopic.php?t=3847
and here:


I've designed and built an external module that can be connected to any ZX Spectrum via the edge connector.

[oO cozy Oo]

@KWF thanks for the info, the reason I was asking because the zx sizif 512 and the zx max 128 uses this module on its own without an amplifier?

sizif bluetooth module

[KWF]

I cannot find any reference to the BT module in ZX Max 128K. I am not familiar with ZX Sizif and how the BT module is connected there, but there is 3.3V TTL logic instead of 5V.

[oO cozy Oo]

I cannot find any reference to the BT module in ZX Max 128K. I am not familiar with ZX Sizif and how the BT module is connected there, but there is 3.3V TTL logic instead of 5V.

Thank you for the reply

On activeconsult web site there is a zx max 128 with a bluetooth module on it, but it looks like its soldered to the board it self? see below on the link.

https://store.activeconsult.co.uk/shop/ ... iewsPage=2

[KWF]

I've checked Sizif512 schematic and the BT module audio output is connected to the Tape In input, biased there and then amplified/converted to square wave using NOT gates (74HCU04 type fed off 3.3V line), and finally wired to 3.3V CPLD.

In ZX Max 128, the audio output of BT module might wired in similar way, with amplification done by Type In (Q9) transistor.

In ZX Spectrum, there is no such think like a pre-amp with single transistor. The EAR input cicrcularity is a bunch of passive components forming high-pass filter with its output connected directly to ULA. ULA needs a bit of "push" for EAR reading, so anything below 2.5-3 V amplitude might be ignored.

[oO cozy Oo]

@KWF
Thank you for the info, so its not straight forward

[KWF]

It would be straight forward if you selected a different BT audio module than MH-M18. There are off shelves modules with embedded audio amplifiers.

[oO cozy Oo]

This is the cheapest way that i have found "Wireless Bluetooth 3.5mm Phone To AUX Car Stereo Music Receiver Adapter "

£2.99 ebay delivered

[KWF]

You are missing the point, because this one is suitable for line/aux inputs and gives low level output signal. ZX Spectrum EAR input needs a bit of power.

[oO cozy Oo]

You are missing the point, because this one is suitable for line/aux inputs and gives low level output signal. ZX Spectrum EAR input needs a bit of power.

I`ve used this and I adjust the sound on my phone you can make it louder

[oO cozy Oo]

Just to finish with me on this issue I found someone on ebay selling zx spectrum bluetooth modules with fitting instructions £4 with £1.60 shipping UK

https://www.ebay.co.uk/itm/394602102724 ... SwsZJkUQlL

[PeterJ]

Has anyone found an external Bluetooth solution that works well?

[mark8bit]

that cheap Bluetooth 5.0 in last reply, i got some this week but haven't had time to fully test yet (plan was more for the +2A & amstrad cpc ) but tested it on a 48k using ear connector and have been unable to load a standard game but to my surprise it loads my OTLA files no problem at all.. one thing i thought of is that maybe the standard loaders i tried are larger wav files that it would have to compress on the fly where as the OTLA loaders are already smaller mp3 that didn't need any compression.. but i have not had time to look at this yet.. also there is a case for it on thingiverse ..