Generic heating / cooling controller describes a bang-bang type thermostat based on a AtTiny25.
This article works up an example application using a Pt100 RTD sensor. Pt100 is the designation for a platinum (Pt) resistance temperature detector with nominal resistance of 100Ω at 0°. Pt has a nearly linear resistance / temperature characteristic and high accuracy. Continue reading Using a Pt100 RTD with my generic heating / cooling controller
The N2006P is a inexpensive PID controller, typically for heating and cooling operations. There are lots of similar devices for under A$20 on eBay.
Above, the controller in a minimal test harness using a Type K Thermocouple for temperature sensing and 40A SSR mounted on a heatsink. (The SSR output should be protected with an MOV for inductive loads.) 480VAC 40A SSRs sell for as little as A$5 on eBay. Continue reading N2006P PID checkout #1
The Slot.it CA20Z is Ford GT40 supplied as a ‘white’ kit which requires assembly and painting work.
Above is the part assembled body after painting with Tamiya X-7 acrylic. Continue reading Slot.it CA20Z build
I couldn’t help myself… I bought a Raspberry Pi 2 (RPi2) to evaluate.
The RPi2 has 1GB of main storage (double that of the earlier RPi B+), and a 4 core 900MHz processor against a single core 700MHz process in the the RPi B+. Continue reading Raspberry Pi 2 initial impressions
Further to AIM 885 produces internally inconsistent results…
A new release, AIM885A appeared recently.
In the common theme of one step forward, two steps backwards, this version produces error popups when started.
The above popup appears twice when starting AIM885A. Just another symptom to undermine confidence in the system. It doesn’t make sense to me, and the program appears to otherwise start and run. Continue reading AIM 885A produces internally inconsistent results
This article builds on Accuracy of AIMuhf system – AIM865A vs AIM882 on a ferrite cored inductor by adding a measurement using AIM885 of the same test inductor.
Above is the test inductor. It comprises 6 turns of 0.5mm PVC insulated wire wound on a BN-43-202 binocular balun core. Continue reading Accuracy of AIMuhf system – AIM865A vs AIM882 vs AIM885 on a ferrite cored inductor
New features in version 885 is
Fixed “Refer to Antenna” function… so lets check it out.
The AIMuhf was calibrated using the supplied OSL components and AIM885.
Above is a sweep of a 1.05m length of Belden 8262 (RG58C/U) cable (with o/c termination) attached to the AIMuhf. Continue reading AIM885 Refer To Antenna checkout
Some time ago I published a calculator for estimating the impedance of RF inductors on toroidal ferrite cores (Calculate ferrite cored inductor).
The calculator (input form above) use the core dimensions and complex permeability as the basis for calculation.
There are some popular cores that are not simple toroids and so not suitable for direct use with that calculator. For these cores, a practical method is to measure the inductance constant Al (inductance of 1 turn in nH) at low frequency (where µ=µi), and using the µ’,µ” characteristic from the datasheets, to calculate the impedance at the desired frequency. Note that µ’,µ” are usually frequency dependent for ferrite materials. Continue reading A new impedance calculator for RF inductors on ferrite cores
I received a sample of speaker wire from a correspondent who asked me to characterise it.
Even if I had the time, a 50mm sample isn’t sufficient to characterise in a meaningful way… but let’s have an abbreviated look which will highlight the pitfalls of this stuff.
First thing to do is measure the conductors, stranding and diameter. There are 14 strands and several measurements fall just below 0.15mm diameter. This is probably nominal 0.15mm with new drawing dies which are a little undersize. Continue reading Speaker wire is so popular as an RF transmission line