Ken Shirriff has written an excellent in-depth look at a Titan missile guidance computer: I’ve been studying the guidance computer from a Titan II nuclear missile. This compact computer was used in the 1970s to guide a Titan II nuclear missile towards its target or send a Titan IIIC rocket into the proper orbit. The […]
Author Archives: DP
DIY long lasting voltage regulator circuit for Raspberry Pi
Jithin @ rootsaid.com writes: Raspberry Pi is simple, handy and cheap yet powerful single board computers of all time. It has USB ports to connect hardware such as pen drive, keyboard, mouse, HDMI port for display out, 3.5 mm port for audio and several GPIO pins to work with embedded projects, all of which can […]
Building my own 50Ah LiFePO4 lithium battery pack
Kenneth Finnegan posted his DIY 50Ah LiFePO4 lithium battery pack build: Several years ago, I had purchased a 20Ah 12V Lithium Iron battery pack from Bioenno for my various 12VDC projects. To help protect it, I ultimately built it up into a 50cal ammo can with a dual panel-mount PowerPole connector on the outside, which […]
Low cost open source ventilator
Johnny Chung Lee writes, “In the event that COVID-19 hospitalizations exhaust the availability of FDA approved ventilators. I started documenting a a process of converting a low-cost CPAP (Continuous Positive Airway Pressure) blower into a rudimentary Ventilator that could help with breathing during an acute respiratory attack. If interested, follow along the Github Project“ More […]
Looking inside a vintage Soviet TTL logic integrated circuit
Ken Shirriff examines a 1980s chip used in a Soyuz space clock: The clock is built from TTL integrated circuits, a type of digital logic that was popular in the 1970s through the 1990s because it was reliable, inexpensive, and easy to use. (If you’ve done hobbyist digital electronics, you probably know the 7400-series of […]
App note: Nonideality of ground
Ground in PCB design, another app note about grounds from Renesas. Link here (PDF) Ground is supposed to be ideal. It should be a black hole for stray currents where the voltage is always zero. Unfortunately, those stray currents travel through some non-superconducting material, so small voltages arise. You may not notice small changes in […]
App note: Grounding techniques
Renesas detailed app note about grounds. Link here (PDF) Ground is taken for granted. We stand on it, we dig into it, we make mud pies out of it. The ground isn’t supposed to move. We don’t have to think about it; it just is. When it comes to grounding a circuit, we assume that […]
AVR high voltage programmer 2
Dilshan Jayakody posted an update on his AVR high voltage programmer project we covered previously: AVR-HV2 is Arduino based high voltage parallel programmer for AVR microcontrollers. This programmer can read, write, and erase both flash memory and EEPROM. Also, this can use to set fuse bits of AVR MCUs. Compare with the previous version of […]
Rothko clock Nixie shield with 6 IN-17 tubes
Florinc writes: This Nixie shield was designed by Tyler around 2013, as an open source project. A little after the successful kickstarter campaign, it just disappeared. I was one of the backers and I received a couple of PCBs for my contribution. I used them to build clocks and I even wrote some review blog […]
Cassette Pi IoT scroller
The Cassette Pi IoT scroller project @ kyliemander.com The Cassette Pi is a self-contained real-time notification scroller, all housed neatly inside a transparent cassette tape. A Raspberry Pi Zero is sandwiched between the two tape reels, retrieving Internet of Things notifications from the fabulous IFTTT service, delivered almost instantly to the Pi via an Adafruit.IO […]
Making an OBD-II solar trickle charger
Kerry Wong shows how to make a simple solar trickle charger: On a few occasions my car struggled to start when I returned from my business trip and I had to charge the battery manually later on by hooking up a charger, which was quite inconvenient. So I decided to make a simple solar trickle […]
App note: DC-to-DC design guide
DC-DC converter design guide from Vishay. Link here (PDF) Manufacturers of electronic systems that require power conversion are faced with the need for higher-density dc-to-dc converters that perform more efficiently, within a smaller footprint, and at lower cost despite increasing output loads. To meet these demands, Siliconix has combined advanced TrenchFET and PWM-optimized process technologies, […]
App note: Torque recommendations for TO-220 devices
App note from Vishay on the impact of torque on thermal resistance of TO-220 devices. Link here (PDF) When the TO-220 was first introduced, most applications required something less than the full power handling capabilities of this package. Hence, the TO-220 is almost taken for granted in terms of its excellent power handling capacity and […]
DIY 18650 Powerwall with onboard BMS
A DIY 18650 Powerwall with onboard BMS @ openhardware.co.za While I cannot afford a Tesla PowerWall, I’ve spent some time drawing up a PCB to house 7x 18650 cells in series. Each board has onboard Battery Management: *Overvoltage Protection (per cell) *Undervoltage Protection (per cell) *Balance Charging *Overcurrent Protection *Main pack Fuse The design files […]
The core memory inside a Saturn V rocket’s computer
A closer look at an LVDC core memory module: The Launch Vehicle Digital Computer (LVDC) had a key role in the Apollo Moon mission, guiding and controlling the Saturn V rocket. Like most computers of the era, it used core memory, storing data in tiny magnetic cores. In this article, I take a close look […]
Building a Raspberry Pi stratum 1 NTP server
A how-to on building a Raspberry Pi stratum 1 NTP server: So this article is going to be my notes on how I built one using a cheap GPS module off eBay as the reference time source and a Raspberry Pi. (a 2B in this case, but hopefully the differences for newer models will be […]
App note: NTC thermistors
Application examples of Negative Temperature Coefficient (NTC) Themistors, app note from TDK. Link here (PDF)
App note: What are Y-Capacitors?
Vicor’s app note about the basics of Y-Capacitors and their uses. Link here When electronic equipment is connected to the AC mains, it has the potential to generate common-mode electrical noise. If this is allowed to flow back on to the mains supply line, it can disturb other equipment also connected to the same line.
Build a DMX FeatherWing to control lights with a Feather M0
Glen Akins writes: This project uses an Adafruit Feather M0 Basic Proto board to control a group of Color Kinetics or other RGB light fixtures using the DMX-512 protocol. We’ll build a DMX-512 interface FeatherWing then connect it to the Feather M0 using a Particle Ethernet FeatherWing. Once the hardware is built and assembled, we’ll […]
Sinilink WIFI-USB mobile remote controller
Peter Scargill blogged about his AliExpress Sinilink WIFI USB controller project: So here’s a thing – I had this all set up and working perfectly with Tasmota on my WiFi – then plugged the unit (USB male end) into a USB3 connector – and it immediately lost the lot – well, the settings, not Tasmota […]