In this video I start to build up the transmitter portion. Not much micropython here unfortunately. I am going to be using a few sources. This is traditional phasing transmitter http://www.arrl.org/files/file/Technology/tis/info/pdf/9304027.pdf and this is one built around the Tayloe mixer seen in the receiver http://www.wb5rvz.org/ensemble_rxtx/index?projectId=14 Specifically this portion http://www.wb5rvz.org/ensemble_rxtx/09_qse I will be building both and comparing. In this video I will build up the Audio phasing section. Schematics and board here: https://github.com/thaaraak/Tinypico-Radio/tree/master/kicad/Transmitter More on Phasing radios can be found in Chapter 9 of Experimental Methods in RF design ... https://www.youtube.com/watch?v=_56MiQ4oBJw

Dan Tayloe's original document http://www.norcalqrp.org/files/Tayloe_mixer_x3a.pdf The Eagle files for the board are here https://github.com/thaaraak/Tinypico-Radio/tree/master/eagle No changes to the micropython source for this video I meant to say LM4562 - https://www.ti.com/lit/ds/symlink/lm4562.pdf A separate debugging video is here: https://youtu.be/EarY64Lf3ls ... https://www.youtube.com/watch?v=iwBk3jIxszI

... https://www.youtube.com/watch?v=HPYLRg0Ju5o

In this video I enhance the clock I started in this video https://www.youtube.com/watch?v=2hyc2fgf3Io&t=1022s with the following: - Use the external low speed oscillator to improve accuracy - Use the MAX7219 LED Driver IC - Include the Time and TimeZone libraries - Use the Beitian GPS receiver My github repo for the code https://github.com/thaaraak/GPS-Clock The MAX7219 datasheet is here: https://datasheets.maximintegrated.com/en/ds/MAX7219-MAX7221.pdf The Beitian GPS receiver is available here (not affiliated) https://www.banggood.com/Beitian-BS-280-232-GPS-Receiver-Module-1PPS-Timing-With-Flash-+-GPS-Antenna-p-1334706.html?akmClientCountry=America&cur_warehouse=CN Here's a link to a simple RX/TX RS232 to TTL circuit http://picprojects.org.uk/projects/simpleSIO/ssio.htm Timezone and Timelib arduino libraries https://github.com/JChristensen/Timezone https://github.com/PaulStoffregen/Time The LED/MAX7219 combo from Amazon https://www.amazon.com/gp/product/B087B8WTRZ/ref=ppx_yo_dt_b_asin_title_o07_s00?ie=UTF8&psc=1 Please Note: There is a bug in the code currently parsing the GPS RMC message. I am using strtok to parse which doesn't work where there are duplicated delimiters. I'll post a fix shortly Update: I added the "zstrtok" function from the zstring library to fix the above: https://github.com/fnoyanisi/zString Index 0:00 Intro 0:51 Using the Low Speed External Oscillator 1:49 Configuring the LSE in STMCube 4:54 The MAX7219 LED Driver 6:40 The MAX7219 Datasheet and capabilities (excuse focus) 8:05 Configuring SPI MAX7219 10:48 MAX7219 SPI write code 11:43 MAX7219 Operation Codes / Registers 13:31 MAX7219 In action 20:48 Using Timezone and TimeLib code 24:14 Local time displayed on the LED 25:18 Converting RS232 voltage levels from the Beitian 280 to 5V 29:55 RS232 signals from Beitian displayed on oscilloscope 30:58 Converted signals displayed on oscilloscope 31:54 Wrap up ... https://www.youtube.com/watch?v=m8SF6exYkSs