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Bluetooth antenna?

I just finished breadboarding that usb keep it live circuit I'd linked to a couple of posts up. It worked first time=) I'd even had to substitute a couple of parts- I used a 0.1uF electrolytic cap instead of the ceramic disc cap and a bc556 instead of the bc177 the designer suggested. I just used what I had...

usb555 test by dik_dolan, on Flickr

I have it clipped onto a usb battery bank and so far (30 minutes now), It pulses a 175mA drain every 10 seconds, which as the designer Ajoy Raman said, does seem to keep this battery bank at least, awake. I'm still waiting on my spare BT modules to arrive, so I haven't tried it on my only one I have yet. I'd hate to kill it doing something stupid=)
Apologies if this is all too much off topic Steve!
 
Not at all off topic, great work. Is that a 555 set up as an astable with a 10s cycle time, turning on the little tranny and lighting the LED? Top class thinking if so.
 
Yep as far as I understand it, anyway. I think most of the switched load is via R4- the 22R- the led is more to just show it's working. I'm quite probably wrong tho. I've forgotten 99.9% of the already scant electronicary knowledge I may have once had. All credit to the gent that came up with the idea and posted it, Ajoy Raman. Here's the link again. https://www.instructables.com/id/Current-Pulsing-Keeps-Power-Bank-Active/
Thank you sir!
Once my spare BT boards arrive I'll give it a proper test, and then try to dead bug build one into a small case with usb in/out.
 
Good scheme. I don't need mine to run off a battery and microscopic power consumption isn't a design aim, so I'l thinking that a 12V generic supply for the amp and a spur off that running a regulated ~5V generated by an LM317 will get it running off one plug.
 
Good point about dead bug building Steve. I've only done it once before many years ago, when I knocked up an inverse RIAA test box. It worked, but if I'd made a mistake it would've been a nightmare to correct. I've got some veroboard that I put away somewhere safe a few (25!) years ago, I'll have to try to find it.

I've also spent the last hour or so watching and reading about kicad and Fritzing. I do like the idea of getting a pcb made. Hmmm, we will see.They look like a whole new world of brain ache=)
 
For something so simple and one off there's no need for a pcb, vero is fine. I used to use it all the time.
 
Oh I totally agree! But I had a very educational afternoon watching and reading about Gerbers, vias, rats nests, silkscreens,masks etc. All pretty much new to me, and I'm still considering trying one or more of the programs out and seeing if I can actually get a clue how it's done- but probably not for this project. Watching some kicad videos made it look as easy as using photoshop when all you're used to is crayons=)
 
Well, my cheap chipamp is here, all of £2.50 or something similar from China. It looks great, I haven't plugged it in yet. No BT module yet, I'll have to wait for next weekend.
 
Shame about the long wait, hopefully your module arrives soon. I'm still waiting for my spares to arrive too, otherwise I'd happily bung one in the post to you.

Which amp did you get? Mine is the TDA7297, like this one. http://rover.ebay.com/rover/1/710-5...0001&campid=5338728743&icep_item=152513987661 It really is excellent and for the price, outstanding=)

A bit off topic, but I've also been eyeing up, and ordering a small mountain of arduino bits to play with. I can feel more headaches incoming. Last bit of programming I tried was on my speccy....... How hard can it be?
 
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Stop press, the bits have now come. I'm blown away with how good they are. The BT adaptor gives a stable connection and runs off a phone charger, no need for any fiddling to keep a power bank alive. In addition it was sent from the best schoolboy joke address ever. Will you believe Elephant Kok Tong Village? Honest. For added sniggering, Tong Village is near me. The BT thing is om a PCB 25mm sq, with power and audio out, that's it. The thing is so small I could just screw it to a bench, or the back of a speaker. Same with the amp. So, shall I put it in a box or just screw it to a shelf? Shall I do both and buy another?
 
Dik Dolan said:
Shame about the long wait, hopefully your module arrives soon. I'm still waiting for my spares to arrive too, otherwise I'd happily bung one in the post to you.

Which amp did you get? Mine is the TDA7297, like this one. https://www.ebay.co.uk/itm/AC-DC-12V-TDA7297-Dual-Channel-2-15W-Digital-Audio-Amplifier-Board-Kit-Module/152513987661?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649 It really is excellent and for the price, outstanding=)

A bit off topic, but I've also been eyeing up, and ordering a small mountain of arduino bits to play with. I can feel more headaches incoming. Last bit of programming I tried was on my speccy....... How hard can it be?
Click to expand...
Surprisingly simple! All the grunt work has been done and its a case of just providing input to macros. If you buy a cheap kit of modules the code comes with the bits so you are up and running straight away. You can then play and see how it works.

Download and install the free adrduino IDE application and you'll see plenty of example code in there already to get you going.

https://www.arduino.cc/en/main/software

Cheers,

DV
 
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Nice one Steve, great aren't they. Mine is all still unboxed- I like seeing all the bare boards and wires=)

Which has lead to:

DV, so far so good. I ordered separate bits from several suppliers, but youtube and google are a godsend. I'm still waiting on quite a few more packages of chinesium do-dads and modules to play with, including small stepper motors, lcd displays from old nokia phones, a bag of plastic gears and wheels, and I'm compiling a list of more sensors and doohickeys I "need". I love this stuff. I'ts dirt cheap and great fun... and educational=)

Been watching many various youtube channels including but not limited to: AVE,This old Tony, Dronebot workshop, Julian Ilett, robojax. Thank you to all of them!
I've no real goal here, just to learn and stretch myself a little with no pressure and pass a lot of time. Stops me from falling back into bad dark places of my mind for a while!
 
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Anyone got a very rough idea how hot the heatsink gets if run loud for long enough to stabilise the temperature?
 
I can't help you there Vinny, sorry. I only ever listen at very low volume and the heatsink barely gets above room temp at those levels.
 
Vinny said:
Anyone got a very rough idea how hot the heatsink gets if run loud for long enough to stabilise the temperature?
Click to expand...
I can report that it gets up to warm skin temperature after an hour of reasonably loud thrashing into inefficient speakers. Not hot, just pleasantly warm. This is in free air, indoors. The thing sounds great, better than it has any right to.
 
Cheers Steve - very helpful.

All the bits plus cables/connectors have arrived, I just need a morning free to rig something up reasonably tidily so that I can judge what I need to buy in terms of an enclosure, allowing for the heatsink being outside of it.
 
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