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Temperature measurements with an NTC thermistor




Following a discussion on Facebook I put here an online tool to calculate the output of a voltage divider consisting of a fixed resistor and an NTC thermistor following a first order Steinhart–Hart equation.

The calculations are based on a voltage divider where either the voltage over the NTC or over the pass resistor is measured. You can change the values in the script according to your own settings. If you break the script for some reason, just reload the page.

SageMath uses Python as programming language.

Not WormFood’s AVR Baud Rate Calculator

This page without a frame: https://sciencetronics.com/uwezi/avrbaudrate.php

.errordiv { padding:10px; margin:10px; border: 1px solid #555555;color: #000000;background-color: #f8f8f8; width:500px; }#advanced_iframe {visibility:visible;opacity:1;vertical-align:top;}.ai-info-bottom-iframe { position: fixed; z-index: 10000; bottom:0; left: 0; margin: 0px; text-align: center; width: 100%; background-color: #ff9999; padding-left: 5px;padding-bottom: 5px; border-top: 1px solid #aaa }#ai-layer-div-advanced_iframe p {height:100%;margin:0;padding:0} var ai_iframe_width_advanced_iframe = 0; var ai_iframe_height_advanced_iframe = 0;var aiIsIe8=false;var aiOnloadScrollTop=”true”; if (typeof aiReadyCallbacks === ‘undefined’) {
var aiReadyCallbacks = [];
} else if (!(aiReadyCallbacks instanceof Array)) {
var aiReadyCallbacks = [];
} function aiShowIframeId(id_iframe) { jQuery(“#”+id_iframe).css(“visibility”, “visible”); } function aiResizeIframeHeight(height) { aiResizeIframeHeight(height,advanced_iframe); } function aiResizeIframeHeightId(height,width,id) {aiResizeIframeHeightById(id,height);}var ifrm_advanced_iframe = document.getElementById(“advanced_iframe”);var hiddenTabsDoneadvanced_iframe = false;
function resizeCallbackadvanced_iframe() {}function aiChangeUrl(loc) {}

Some Toner-Transfer PCB Highlights

Some recent highlights from my home-made circuit boards using the toner-transfer method.

0.5 mm FPC breakout board

Yes, I have been told that I am crazy before… Designed in KiCAD

0.5 mm pitch FPC breakout board – before etching

0.5 mm pitch FPC breakout board – half-way etched

Continue reading Some Toner-Transfer PCB Highlights

Canvas: Using Python to create Calculated Questions

Background

I just recently started with Canvas because Uppsala University has decided to use it as its upcoming LMS platform after a failed attempt with another product. Therefore I had already spent some time with Blackboard and was quite fond of the calculated questions type in quizzes. I quickly found out that Canvas offers […]

Continue reading Canvas: Using Python to create Calculated Questions

A tiny watchdog

In a recent quick-and-dirty project with a Wemos D1 mini clone I had some problems with the reliability of the code. The ESP8266 contains two watchdogs which have the sole purpose to reset the chip if the firmware ever should get stuck. Previously I experienced these watchdogs to be too aggressive, but this was […]

Continue reading A tiny watchdog

Hacking IKEA trådfri lighting automation

I recently visited IKEA again and got interested in their affordable line of home automation/LED lighting products called TRÅDFRI (meaing wireless in a play-with-words kind of Swedish). Of course there was already an internet community active in hacking these devices and I joined in.

Getting started

I installed the gateway and after pairing devices […]

Continue reading Hacking IKEA trådfri lighting automation

project update: a TTL/CMOS computer

Exactly one month later – our electronics course at Uppsala University just approaches its end – and I got the next shipment for my new project: 1.1 km of equipment wire.

new project: a TTL/CMOS computer

Watching Ben Eater’s youtube series on his breadboard computer based on discrete logic chips inspired me to pursue my own construction. Apart from a lack of time I also needed some more breadboards, which arrived today.

twenty new […]

Continue reading new project: a TTL/CMOS computer

A visitor on the balkony

http://www.sciencetronics.com/greenphotons/wp-content/uploads/2018/02/20180226_balkong_malmabacke.mp4

Top deal of the week?

Today I received a newsletter from the publisher Elektor. I am offered a special deal on a Peltier power generator which can power an LED light from a small candle. And this for an astonishing price of €99.95 instead of the normal price of €119.95.

Great offer from Elektor.

I’ll have to […]

Continue reading Top deal of the week?