About Me
My name is Roger Meier, and I am an Electrical Engineer who likes to tinker with hardware and code in his spare time.
On this page, you will find some of the hardware projects I have worked on over the years.
I also host several freeware and open-source projects that you might be interested in.
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Donations
If you think my work is useful to you and would like to donate, please click on the button below.
Disclaimer
THE SOFTWARE TITLES ON THIS WEBSITE ARE PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF THIRD PARTY RIGHTS. IN NO EVENT SHALL THE AUTHOR OR AUTHORS AND COPYRIGHT HOLDER OR HOLDERS OF THESE SOFTWARE TITLES BE LIABLE FOR ANY CLAIM, OR ANY SPECIAL INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THESE SOFTWARE TITLES.
Harware Projects
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There is no better way to annoy your loved ones than blasting them with dad jokes all day. However, you may not always be available to do so when things like your day job get in the way, etc. For the source code, wiring diagram, STL files, etc, download the project archive, using the link to the left. |
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This project uses Amperex ZM1005 nixie tubes salvaged in the 1980s from an old Dana digital benchtop voltmeter. The footprints on the PCB are compatible with ZM1000 and ZM1005 tubes from Amperex, Phillips, etc. However, the circuit should also work any most other Nixie tubes (adjust the booster supply voltage accordingly). For, schematics, PCB files, source code, STL files, etc, download the project archive, using the link to the left. |
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Reusing the hardware from my Termi3 project below, this adds ChatGPT functionality to the TI Silent 700 terminal (or any other retro terminal or computer with an RS232 port). This project is written in MicroPython and runs on an ESP32, using the "gpt-3.5-turbo" model of the OpenAI API. For the source code, download the project archive, using the link to the left. |
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This is a simple build that combines a USB to Serial UART adapter with a Text-to-Speech module and an audio amplifier with speakers. For my version, I used an FTDI UBM232R module, an Emic-2, and a cheap Amp/Speaker kit from Amazon. For a wiring diagram, STL files for the enclosure, etc, download the project archive, using the link to the left. |
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Apr-2023 |
Termi3 is an update of Cameron Coward's excellent Termi2 project. Just like Termi2, Termi3 also runs on an ESP32 with MicroPython and reuses much of Cameron's code, with some enhancements such as special character handling, support for back space to fix typos (very important :-)), recovery from a loss of network without needing to reboot, the ability to prompt the user for new WiFi credentials in case the the setup is moved to a different location and the currently configured WiFi network can't be found, and the support for a configuration menu that lets the user change some basic settings. My project updates the hardware for use with newer TI Silent 700 terminals such as the 703 which can communicate at 1200 baud. It also takes advantage of the TI Silents acoustic coupler port to provide power to the ESP32, thus eliminating the need for an internal battery. Signal level shifting between the TI Silent and the ESP32 is done via a MAX3232 RS232 to TTL level shifter module. The DTR signal from the TI Silent is used to control the EN signal of the ESP32, making it possible to reboot the controller with the "ON LINE" switch of the TI Silent (which can be handy :-)). I may publish a full-fledged Instructable at some point, but meanwhile, you can download the project archive, which hopefully includes enough information for others to be able to build it, using the link on the left. |
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- Teensy 4.1 microcontroller board |
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A clock built with a flip-dot display, driven by NCV7719 half-bridge drivers controlled by a Teensy 3.2. |
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Taking advantage of the versatility of the Emic 2 text-to-speech module, this project creates a fun Halloween prop that is pretty effective in startling trick-or-treaters. The project archive with the Arduino code, parts list, and wiring instructions can be downloaded using the link on the left. |
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A very simple hack using lowpass filters on the VGA color signals and an Arduino that generates PWM from the filtered signals driving an RGB LED strip. The project archive with the Arduino code and schematics can be downloaded using the link on the left. |