I have to give Elecrow a shoutout for excellent service. I have ordered several batches of printed circuit boards over few months. For most of these, i sent the files Sunday evening (in the US) and i have received the boards Monday of the following week. This was using the standard processing time option and DHL Shenzeng shipping. I usually order a few different boards at a time or some other stuff so I can't say exactly what the shipping cost for a single batch of boards would be, but it's about $20 - $25. If you've shipped anything by UPS or FedEx recently, $25 from the far side of the world is not unreasonable.
The service for my latest batch of boards was unbelievable. I submitted the files Tuesday night...and had the boards the next Monday! Standard processing time and DHL shipping as above.
Still stuck on the board design stage but I'll have that figured out soon enough. Weird that this stage of my game is what is holding me up. I have everything else I need to get my bread-boarded ideas on tiny boards. What is a WTT Beeper if I may ask?
WTT = Wales Turbulence Timer, the project I've been working on forever with the FAA. The timers have undergone a year of testing at airports in the northwest, with excellent acceptance.
A request was made to be able to adjust the volume of the magnetic beeper that signals the end of a countdown period. Turns out this isn't a simple task! The board is an audio replacement to provide adjustable volume.
A square wave oscillator feeds an integrator to make triangle wave - high frequency harmonics rolled off - to provide a more pleasant tone. From there, a digipot controls the level into a power amp. The amp drives a 12mm speaker that can belt out a surprising volume.
This board hangs off the ICSP connector to control the digipot using I2C. The control line for the normal beeper turns the amp on at the appropriate times.
Pretty cool! I searched for it here and didn't find anything. Is this for small aircraft or commercial? Some terminology here to search on though. Especially the digipot. It seems there is a device for anything that can be controlled by I2C or SPI.