{"id":17227,"date":"2023-06-21T23:11:32","date_gmt":"2023-06-22T03:11:32","guid":{"rendered":"https:\/\/scruss.com\/blog\/?p=17227"},"modified":"2023-06-22T09:26:37","modified_gmt":"2023-06-22T13:26:37","slug":"speech-from-python-with-the-syn6988-module","status":"publish","type":"post","link":"https:\/\/scruss.com\/blog\/2023\/06\/21\/speech-from-python-with-the-syn6988-module\/","title":{"rendered":"Speech from Python with the SYN6988 module"},"content":{"rendered":"\n

I’ve had one of these cheap(ish – $15) sound modules from AliExpress for a while. I hadn’t managed to get much out of it before, but I poked about at it a little more and found I was trying to drive the wrong chip. Aha! Makes all the difference.<\/p>\n\n\n\n

So here’s a short narration from my favourite Richard Brautigan poem,<\/a> read by the SYN6988. <\/p>\n\n\n\n

Sensitive listener alert!<\/strong> There is a static click midway through. I edited out the clipped part, but it’s still a little jarring. It would always do this at the same point in playback, for some reason.<\/p>\n\n\n\n

The only Pythonish code I could find for these chips was meant for the older SYN6288 and MicroPython (syn6288.py<\/a>). I have no idea what I’m doing, but with some trivial modification, it makes sound.<\/p>\n\n\n\n

I used the simple serial UART connection: RX -> TX, TX -> RX, 3V3 to 3V3 and GND to GND. My board is hard-coded to run at 9600 baud. I used the USB serial adapter that came with the board.<\/p>\n\n\n\n

Here’s the code that read that text:<\/p>\n\n\n

\n#!\/usr\/bin\/env python3\n# -*- coding: utf-8 -*-\n\nimport serial\nimport time\n\n# NB via MicroPython and old too! Also for a SYN6288, which I don't have\n# nabbed from https:\/\/github.com\/TPYBoard\/TPYBoard_lib\/\n\ndef sendspeak(port, data):\n    eec = 0\n    buf = [0xFD, 0x00, 0, 0x01, 0x01]\n    buf[2] = len(data) + 3\n    buf += list(bytearray(data, encoding='utf-8'))\n    for i in range(len(buf)):\n        eec ^= int(buf[i])\n    buf.append(eec)\n    port.write(bytearray(buf))\n\nser = serial.Serial("\/dev\/ttyUSB1", 9600)\nsendspeak(ser, "[t5]I like to think [p100](it [t7]has[t5] to be!)[p100] of a cybernetic ecology [p100]where we are free of our labors and joined back to nature, [p100]returned to our mammal brothers and sisters, [p100]and all watched over by machines of loving grace")\ntime.sleep(8)\nser.close()\n<\/pre><\/div>\n\n\n
This code is bad. All I did was prod stuff until it stopped not<\/em> working. Since all I have to work from includes a datasheet in Chinese (from here: ??????-SYN6988???TTS????<\/a>) there’s lots of stuff  I could do better. I used the tone and pause tags to give the reading a little more life, but it’s still a bit flat. For $15, though, a board that makes a fair stab at reading English is not bad at all. We can’t all afford vintage DECtalk hardware.<\/p>\n\n\n\n
The one thing I didn’t do is used the SYN6988’s Busy\/Ready<\/em> line to see if it was still busy reading. That means I could send it text as soon as it was ready, rather than pausing for 8 seconds after the speech. This refinement will come later, most likely when I port this to MicroPython.<\/p>\n\n\n\n
More resources:<\/p>\n\n\n\n