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Open Source Hardware

90 posts
I had hoped to to have completed the basic design by now but I've spent a lot of today thinking about power supplies, but not getting quite far enough to commit to paper (or CAD). The idea was always to have a a separate power conversion board, so there is no reason that the rest of the design can't be offered up for discussion without the psus.   All the schematics will be posted as .pdf s but it's probably easier to have the blurry .jpgs in this blog for instant reference.   I' ...
15/08/2020 This is still very much work in progress.   I've confirmed my primary choice of display, the Riverdi RVT43ALBFWN00, available from Mouser and RS. It has an SPI interface over a 20 way FPC and uses a Bridgetek controller chip. This is fairly smart and reasonably well documented chip and very much mitigates the slowness of controlling a hi res display over SPI. It costs about £27.   Here's a picture - of the important side !     The plan is that the disp ...
Overview   Once again there are few (if any) component vlaues on the schematic, these will appear in the BOM later on. Treat the pin numbering on the FPFA with caution, I shall swap pins as appropriate when I layout the board.     The Details   The DAC digital interface is forced to SPI mode by pulling pin SPI2C low. The FPGA drives it s three SPI signals (the DAC can't return any data to the FPGA. The analogue signal from the DAC is low pass filtered by the Sallen an ...
This is my first stab at the input amplifier for the Archaeology Resistance Meter Project. It's tagged as armp   Overview The schematic has (almost) no component values but I shall talk about them in the text. All two terminal components are in 0603 packages unless marked otherwise.   A better print of the schematic is uploaded as a .pdf in Open Source Hardware   The original plan was that the maximum possible (working) input voltage would be +/- 15V but comments from dav ...
Introduction Overview Using the Code Settings Section Functions Section Main Code Section Putting it all Together Summary   Introduction For a recent environment sensor project I wanted to make use of an analog moving-coil meter. They are still manufactured and available new from Aliexpress for very little, and are also available from what I’ve heard, from Ham radio meet-ups.   They can be driven from analog circuits, or from microcontrollers and ...
I've been covering the engineering and maker communities for over a decade now, and it never ceases to amaze me when these communities come together to solve complex issues. Take for example the E-Nable Project. Engineers, Makers, and Citizen Scientists teamed up to create open-source, 3D printable prosthetics for children that anyone with a 3D printer and basic tools could create. Likewise, a new group on Facebook has been created to bring those same groups together to collaborate on designing ...
The blog post here is just a place to put files and diagrams related to an electret microphone element amplifier circuit that is intended for basic sound or speech applications. The circuit is based on requirements from  BigG  and analysis from michaelkellett. It was created as part of a discussion in the comments here: https://www.element14.com/community/message/289305/l/trying-to-understand-how-r-c-affect-an-audio-signal-when-used-in-a-… That discussion can be referred to, ...
Introduction How does it work? Building a Temperature Sensor Summary   Introduction This blog post describes a really simple (near-trivial) project – wiring up a thermistor!   Thermistors are great, but have a limited operational temperature range compared to (say) thermocouples. The aim was to use a thermistor for fast, accurate ambient temperature measurement because this is handy for checking the room for those who are slightly obsessive over their environment ...
Hi, I've got some items unrequired, if you're in the UK and wish to have it, please let me know if you want "chemistry" or "LoRa" or "Heating" stuff and I'll post it for free. All of this stuff is new and unused, and I hate to just throw it away since it's quite useful stuff.   Chemistry stuff: 6 x 100ml beakers (glass), a plastic funnel, 4 glass pipettes and some boxes of universal indicator (like Litmus paper).     LoRa stuff: Two SX1276MB1MAS (European variant) LoRa transc ...
shabaz

Building an LCR Meter

Posted by shabaz Top Member Jul 23, 2019
Introduction Recently there's been lots of interest in capacitor equivalent series resistance (ESR) and many other capacitor topics (e.g. see Deep Dive into ESR, Introduction  and Capacitor Leakage Experiments and Experimenting with Polymer Capacitors ). This blog post briefly discusses how to build a tool that can attach to a PC, in order to measure the impedance of components. For a brief overview of impedance, and why it can be important, see Measuring Capacitor Characteristics   ...
This post documents an enclosure for the milliohm meter described here and is a tale of how the mechanical bits are often as difficult to get right as the electronics.  The meter parts have been stored away, and thus it was not really available due to the lack of an enclosure.  Today I finally got around to putting it all together.   Here it is all wired up but outside of the enclosure: I am not that pleased with the wiring - too easy to bump loose and not that tidy - but easy ...
Introduction For open source projects, I usually create a table containing the parts details or bill of materials (BoM), but it is tiresome to then re-enter all that information into the Farnell or Newark website, to order the bits.   The March 2019 update to the element14 website contains the ability to paste BoM content and it will auto-convert into a nice table with hyperlinked buttons to go directly to the Farnell/Newark product page for each component, or a single-button to purchase a ...
Note: This is part 2 of a two-part project. For first part, see here: Building a Low Cost Solder Fume Extractor – Part 1   Introduction This project concerns a solder fume extractor that does as the title suggests, and sucks up solder fumes from soldering irons : ) It consists of a box containing multiple fans and filters, and a hose attachment with a funnel on the ingress side, and an egress side with the control/connectors. There is also an 'Aux' port, for additions such as LED la ...
This post documents the first working Version 1.3 of an inexpensive but reasonably accurate meter for measuring resistance in the milliohm range. The development to date is documented in the links at the bottom of this post.  Version 1.3 contains numerous upgrades and suggestions from Shabaz, Gene Breniman, John Wiltrout, and Jon Clift to which I am indebted.   It's Alive! Those who were following the project may have given up it has been so long since the last post.  The reas ...
Looks like there is a new Xilinx Spartan7 board on the market!       The S7-Mini board has been officially launched at Embedded World 2019, by Trentz Electronic, a German company specialized in the design of high-speed data acquisition, high-accuracy measurement and embedded digital signal processing systems based on FPGA and CPU architectures.   The design of the prototype board comes from last year collaboration between  Black Mesa Lab and OSH Park, which is now ...

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