(Kai Hofmann) #423

Workbench question:

I have one of these 6V block batteries for road works laterns (don’t know the right english name :wink:
So I wonder if it is an good idea to use this for my things uno … but what I can’t find outside is a type of battery holder for this 6V type. Because I hate to solder cabel directly to the battery - does someone of you know if such a thing exist?
Otherwise I have to construct one myself …

(LoRaTracker) #424

A lot of people have probably never have seen the battery inside of a road work lantern, why would they, so perhaps you could provide a picture, to avoid confusion ?

(Kai Hofmann) #425

Done, thanks for the hint.

(Jeff Uk) #426

Often also used in longer life/higher current portable consumer appliances e.g. I have an old Roberts AM/FM/SW radio of late mothers that used two dating from late 70’s/early 80’s as well as such ‘industrial’ apps. Typically type 4R25 or aka 996 6V.

(LoRaTracker) #427

Ah the one with springs.

I have openened up some of those, a long time ago I would say, and they were just D cells inside.

So why do you want to use the 6V lantern battery, do they have more capacity versus D cells ?

D cell battery holders are easy to find.

(Kai Hofmann) #428

I can’t belive that there are 4 D-Cells inside :wink: But maybe something that looks similar.
For me it would be nice to use them, because I have them at hand - so why only using them for the latern?
Would also be nice to know how long a thinks uno could work with one.

(Jeff Uk) #429

Besides torches, lantern & portable radios I think these are also much loved by Ducati motor bike owners - the battery typically sits on a steel or carbon fibre plate but not sure what connector is used - may be worth approaching your local Ducati owners club or motorcycle outfitter/supplies shop?

I often power higher powered LoRa kit (base stations etc.) for pop up/short term test deployments using 3000/5000mAH rechargeable USB power banks but typically such devices dont like low duty cycle low current devices and shut off about after as few tens of seconds as they think there is nothing connected! so for such devices I have used a PJ996 6V or pp3 9V type feeding a 5-24v input dual usb 5v output adapter such as those readily available on ebay and use that for nodes with usb power inputs (LoRaMOTES or RAK811 senor/tracker bds etc. if the uno takes such a feed (havent looked) then with a power adaptor you should be good to go. sorry cant help with the actual spring connectors - i just use flying leads with either pop on battery connector (for the pp3) or croc clips for the 996’s (not permanent deployments just test tests/pop ups as I say…). Have also just bought a bunch of these 18650 adaptors similar to Borroz suggestion above
image…a bit more compact than the 4R25/996 :wink: and rechargeable :slight_smile:

(Jeff Uk) #430

Can you recall if that was reputable brand? Have seen cheap or fake C cells where there is just a single AAA inside and cheap/fake D cells with single C cell and even a single AA inside! When I dismantled old 996’s years ago they seem much more complex…maybe manufacturers cost cutting now on less frequently used form factors …or may be fake/cheap clones? When next 996 dies will make a point of dismantling rather than just throwing in recycle bucket and look for myself :wink: (couple of EveryReady Mercury-Cadmium Free units are near EOL so not too long now!)

(Kai Hofmann) #431

Nice to know that such a thing is available - I have searched badly for some kind of this.
Thats because I bought by accident :wink: some of these ESP32:


And in the first round I added 1,27mm pins to it:

Which was not very wise, because I can’t find your half-sized breadboard :wink:
But I found another (better) solution on amazon:


Not my best soldering, but I really hate these small things - so in the end it looks like this:

Hopefully this will work - have not tried it yet.
Btw. whats the smallest LoRa part to make an ESP32 work with?

(Kai Hofmann) #432

Just to show you that my C64 has nearly the same color as your cartridge :wink:


and from inside:


(LoRaTracker) #433

Too long ago to recall.

What is the capacity of those ‘lantern batteries’ compared to a D cell ?

Alkaline cells are cheap enough in the UK, Poundland, Ikea, Maplin etc.

Anyway soldering wires to the springs is very easy, they is virtually no risk of heating the battery itself.


I used them to, very long time ago, didn’t know they still exist :sunglasses:… inside are 4 D cells… not complete, but only the ‘core’… so yes its equal to 4 x D in series = 6 V


finally I did it… I ordered an E paper display on eBay
small one because they are still a bit expensive
its really my first one… I’m a bit emotional now :crazy_face:

inspired by some vids and articles

(Kai Hofmann) #436

e-paper is a nice thing, I am playing around with this one:

Has 7,5" for 59€ and is compatible with raspberry pi, arduino and esp32.


yes that’s a very nice one !
I’ve seen this VID

only thing I never understand, be it TFT / LCD whatever… they never offer a nice way to mount these displays … the end result always looks … well… DIY imho

  • what are your experiences with E paper displays… for example ’ they don’t have a backlight, can you still read them in lowlight conditions ? ’

(Kai Hofmann) #438

I use it as a todo list reminder/calendar inhouse - so I don’t really have lowlight problems, because my light goes on when the roller blinds shutdown, and they did, when the sun goes down :wink:
The only thing I am really missing is touch for e-paper … best would be a DIN A4 epaper with touch - that would be a great thing.


what about mounting this on the front …

(Gry Kyo) #440

Power projects…

Oh, man! These looked so much bigger in the Aliexpress photo!

Where did I put my +1’s? :eyeglasses:


LOL. +3’s :eyeglasses: will do great. :sunglasses:


test button with buildin LED (reset / Tx)