In this blog we will experiment with vacuum tube logic gates. We will be using low voltage so it is totally safe. We will use a 6al5 twin diode tube. In the circuit below shows how to use it as semiconductors diodes but it’s very same as for vacuum tubes. Simply wire positive and negative …
Author Archives: Justin Roeder
Capacitance substitution board
In this blog I will show you how to make a dip switches capacitor substitution board. Its very simple since capacitors add up in parallel. So if you look at the schematic you will get an idea.
USB charger data voltages
You may be thinking that usb charging devices use just the 5v and ground wires? Well your wrong as those devices don’t want to break the charger by drawing too much current. They require certain voltages on the 2 data lines. It took me alot of research to figure out how to configure it. If …
Simple doorbell/alarm
This is probably the simplest doorbell or alarm circuit that is out there. The buzzer will not be constantly on since the buzzer gets switched on by a capacitor. The circuit draws hardly anything when off as you will see in the graph below. As the capacitor gets charged its current lowers down a lot. …
Arduino Video poker for the TV
Here is a project I have been working on. It hooks up to the tv and allows you to play 5 different types of video poker games. The game is in black and white and some of the suits look funny. The pinouts can be found in README.MD file. Youtube videos
Birthday Project 2022
Here is the birthday project of the year: TV Arduino Video Poker machine with real poker machine buttons.
Serial Port PWM
In this blog I will show you how to generate pwm with a computer with a serial port. This tool was originally written by subcooledheatpump from YouTube. I made it better where you can choose which com port to use(by command-line or by being prompted to do so). Controlling it is now better since now …
The simplest in-circuit transistor tester
This is the simplest in circuit transistor tester. It uses two ammeters to measure the transistor gain. It is kinda like the heathkit IT-18 one but uses 2 meters instead of one. I plan on using relays for the polarity switch instead of a 5PDT Rotary switch. It uses a LM317 regulator for providing a …
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Offline, online and reconnect tool
This tool checks the internet connection to see what Internet Provider your using. Good for VPNs and getting your server back online. You can use reconnect.bat file to help fix network problems or alert you when you lost connection or your ISP Name has changed. To make your batch detect first open your command prompt …
How to make the computer talk from any batch file
It is possible to make the computer talk by a batch file or any windows program. All is needed is a tiny VBScript file that use Microsoft Speech API OLE Object. Also all sentences passed to the command must be surrounded with quotes. Otherwise it will not sound the best. You may download, copy, modify …
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Circuit Simulator