Ian Wraith designed and built a low cost 2-4 GHz downconverter for an SDR, that is available on Github:
I recently became interested in exploring some of the signals found in the 2.4 GHz ISM band. The problem is that my favourite SDR (Software Defined Radio) an Airspy R2 only covers up to 1.7 GHz. Initially I looked at buying an SDR that could cover the 2.4 GHz band but found either that they were to expensive , had poor performance or weren’t supported by my SDR control software of choice. So I decided it would be best to build a downconverter to take the 2.4 GHz down by 1 GHz so it could be monitored by my Airspy.
MAKERVILLA is back! It will be held 31 July – 2 August 2019 at the National Design Centre Singapore.
MAKERVILLA 3.0 is a 3-day creative learning experience (CLX) design conference for local and international makers, practitioners & educators to gather under one roof for a time of learning, dreaming, hacking and sharing of ideas.
Find out more on their website at makervilla.com. Mark your calendar!
Boris Landoni over at Open Electronics writes, “We use the platform based on the AMS sensors in combination with the Personal Computer and thanks to an ad hoc software we trace on the screen the spectrum curves resulting from the analysis performed.”
More info on Open Source Project page.
Josh built this 6CY7 dual triode valve amplifier:
I’ve always wanted to know what the “tube magic” was all about. There is much opinion in the science of music production, probably because music and its perception is highly personal and subjective. Ive always imagined that since transistor amplifiers were “perfect” with their large amounts of negative feedback, great linearity, and low THD that tube amplifiers must add something to sound that generates their appeal. From the reading I’ve done it has to do with harmonics.
More details on imsolidstate blog.
Another app note from ON Semiconductors about various digital potentiometers application. Link here (PDF)
Analog circuits are made programmable by using digital potentiometers (POTs) to vary the key circuit parameters. This application note provides the analog design engineer with basic reference designs and circuit ideas for controlling the key parameters of analog circuits using digital POTs connected to a computer bus or microcontroller. Analog circuits are made programmable by using digital potentiometers (POTs) to vary the key circuit parameters. This application note provides the analog design engineer with basic reference designs and circuit ideas for controlling the key parameters of analog circuits using digital POTs connected to a computer bus or microcontroller.
Controlling LED brightness through digital potentiometer and a LED driver from ON Semiconductor. Link here (PDF)
Light-emitting diodes (LEDs) require a regulated current, and their brightness is proportional to the current that flows through them. Some LED drivers use an external resistor to set the LED current. A digital POT can replace a discrete resistor with the advantage of providing an adjustable value allowing the LED brightness to dynamically change. Most digital POT circuits have the ability to store permanently the resistor value in non-volatile memory.
Run a Korg SQ-1 Sequencer from a 9V Stompbox supply:
The Korg SQ-1 is a great little sequencer, and one of my favourite bits of kit for its simple hands-on feel and penchant for lucky randomness (I have 3 of them!)
I tend to use it in a live setup with no computer but with a lot of guitar effect pedals on 9V daisy chain cables. The fact that the SQ-1 can only use batteries or USB power becomes a bit annoying so I decided to hack one so it can run on the same power supply as the pedals.
More details on Stuff and Nonsense blog.
Dilshan Jayakody writes:
Simple NTP clock is a maintenance-free clock application developed to work on single-board computers like Raspberry Pi, Orange Pi, etc. This clock application uses the Simple Network Time Protocol (SNTP) to get the time and display it on seven segment display which I designed. This application is designed to work on most of the Linux based systems and had minimum dependencies with system libraries and peripherals. I developed this application to work with Allwinner H2 Plus based Orange Pi Zero board, but this can compile for other platforms without doing any modifications on the source code.
See the full post on his blog.
Ken Shirriff implemented the SHA-256 hash algorithm and ran it on the vintage Apollo Guidance Computer (AGC) that they’re restoring:
We’ve been restoring an Apollo Guidance Computer. Now that we have the world’s only working AGC, I decided to write some code for it. Trying to mine Bitcoin on this 1960s computer seemed both pointless and anachronistic, so I had to give it a shot. Implementing the Bitcoin hash algorithm in assembly code on this 15-bit computer was challenging, but I got it to work. Unfortunately, the computer is so slow that it would take about a billion times the age of the universe to successfully mine a Bitcoin block.
See the full post on Ken Shirriff’s blog.
From the comments on our ESP8266 temperature logger post, Edward Mallon writes:
The ESP8266 has a hardware watchdog timer, so you could probably use that to measure temperature to much better resolution that you’d get from a DS18B20. We get better than 0.003C using the technique with cheap Pro Mini Clones
Ooops, I missed an important aspect of the two clock method – the inter-reading jitter in the micros() reads brings the resolution down to DS18b20 levels.
More details on Underwater Arduino Data Loggers blog.