100 lines
3.5 KiB
Markdown
100 lines
3.5 KiB
Markdown
# NixiESP12
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## Intro
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Yet another Nixie clock project!
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Some highlights:
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* K155ID1 driven IN-12A or IN-12B tubes for hour, minute, seconds. Use 36k resistors on these tubes.
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* BS108 driven IN-6 or [similar 4*10mm neon bulbs](https://www.aliexpress.com/item/32344955038.html?spm=a2g0s.9042311.0.0.6ab14c4dCxpPZ0) for digit separation. Use 270k resistors on these bulbs.
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* 74HC595 for serial to parallel conversion
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* ESP8266 for time synchronization. Use 1k resistors for pull-up.
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* LM1117-3.3V and LM1117-5V regulators for logic power supply
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* No tube step up converter on-board, pin headers for connecting
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<a href="http://www.ebay.com/itm/DC-5V-12V-to-170V-DC-High-Voltage-NIXIE-Power-Supply-Module-PSU-NIXIE-TUBE-ERA-/322511957768?hash=item4b1735ef08">third party power supply</a>
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* KiCad design with 3D models from http://miniwatt.info
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Some KiCad screenshots:
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<img src="https://git.k-space.ee/lauri/nixiesp12/raw/master/nixiesp.png"/>
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## Install
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Install dependencies on an Ubuntu 18.04 box:
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```bash
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apt install -y python3-pip wget picocom make
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pip3 install adafruit-ampy esptool
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```
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Boot ESP8266 with program pin held low and flash MicroPython:
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```bash
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cd firmware
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make erase
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make flash
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```
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Reboot ESP8266, open serial to to the controller and format filesystem:
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```
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import os
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os.umount('/')
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os.VfsLfs2.mkfs(bdev)
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os.mount(bdev, '/')
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```
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Finish with by uploading scripts:
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```bash
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make upload
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```
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Power cycle the device and via WiFi connect to the device,
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network name is MicroPython-XXXXXX and password is micropythoN.
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Navigate to http://192.168.4.1 to start the configuration wizard.
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## Configuring
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If firmware is unable to connect to preconfigured wireless network
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or it is started up for the first time wireless network
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with password `micropythoN` is created.
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Connect to that wireless network and open http://192.168.4.1
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in web browser to configure the clock.
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## Assembly tips
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Some cheap 1117V regulators don't offer short circuit protection
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and once blown pass through input voltage,
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make sure you get ones with protection otherwise you can fry ESP8266
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or serial-to-parallel chips.
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Once the PCB is milled or etched make sure you clean the 180V rails thoroughly,
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that voltage is high enough to cross gaps of 0.1mm.
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Once that happens it burns a thick dark trace into the fiberglass of PCB and
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it's pretty tricky to clean up.
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The PCB is designed with 0.4mm clearance to be compliant with HV designs.
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This clearance of course assumes that PCB traces are covered.
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Either use solder mask or conformal coating.
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Use the bench power supply to gradually power up the device,
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at 9V set current limiter to 0.5A max.
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5V linear regulator can be omitted and bypassed if 5V wall adapter is always used.
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Otherwise 6V-12V wall adapters are suitable,
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Thincan DBE60 9V wall adapters are pretty much perfect for the job.
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Note that the higher the input voltage the more power is dissipated
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as heat on the 3.3V and 5V voltage regulators, thus at 12V the device gets really hot.
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## Debugging
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* If you get nonsense reading during boot up sequence 0..9 likely the connection between serial-to-parallel chips and high voltage drivers
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is flaky. Either there are shorted pins or there is no connection at all. Check soldering joints and check for shorts between lines and line to ground.
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* If single tube doesn't light up likely the gas has escaped the tube, find replacement tube.
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* If single digit does not light up likely the tube socket pin is mangled or it is not properly soldered on the side where the PCB trace runs.
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