[DECtalk] Fw: Looking for a home for a couple of serial synths
Text_to_Speech at GMX.com
Thu Sep 9 10:29:21 EDT 2021
On 9/9/2021 3:08 AM, Tom Kopec wrote:
> A DECTalk Express should power-up OK on external power with a dead/missing
I'd have to check that. It might rely on the battery as a voltage clamp.
> The battery uses 600mAh prismatic ni-cad cells, which are very difficult to
> find.. I don't think they are in current production.
> I have seen some Chinese NiMH cells that might sort-of work, but the charger
> circuitry is not compatible with NiMH cells.
And, the different chemistry will yield a different, overall, "battery"
voltage (9V -- 7.5 if you opt for just 5 cells -- instead of 7.2V)
> There isn't a lot of room in there to hack in another solution. With
> significant hacking it is might be possible to convert to a lithium battery,
> but that's not plug-and-play.
Again, different chemistry means yet another incompatible battery
voltage (likely 8.4V instead of 7.2). Though you can likely
find some flat "bag cells" and *possibly* trick them into
fitting in the available space.
[I can't recall if the DX reports battery status as this would be
another aspect of operation that would be altered. "Low battery"
may not be!]
The smarter approach is to design a pack that sits outside the
device (or, at least interfaces to the power inlet). This gives
you a bit more leeway on characteristics and capabilities.
E.g., a pair of 18650's would likely power the device for
a whole (solar) day!
But, at the end of the day, it's still a pretty big box for what
it does. Compare to the synthetic speech you get from a cell phone
(that easily fits in your pocket and runs all day).
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