Flashing LED driver using an ESC described a LED driver for an animal deterrent using a repurposed brushless DC motor electronic speed controller.
This article describes a simpler implementation based on a Chinese 8051 architecture microcontroller, the STC15F104E.
Above, the schematic. A very simple circuit with just a handful of electronic components (one capacitor, two resistors, one LDR, one Polyswitch, 4 x LEDs and the MCU). Continue reading Fox flasher MkII
This is a review of an inexpensive MH-1210 Chinese bang-bang thermostat that was purchased on eBay for around A$13 complete with thermistor sensor and postage.
This one was a replacement for one incorrectly sent (wrong supply voltage).
Above is the thermostat. Continue reading Review of inexpensive Chinese thermostat – MH-1210 #2
I wanted to embed some thermistors in battery packs to use them with CBAIV and sought specifications from Westmountain Radio who declined to supply the information.
It is a straight forward matter to measure the resistance of a thermistor immersed in a stable bath of water, and similarly to observe the software response to standard resistors. Continue reading Thermistor for CBAIV
After almost 50 years working with 8bit microcomputers and microcontrollers, I thought it about time to get my hands dirty on some 32bit microcontrollers.
The plan is to investigate two streams, one ST Microcontoller based and one ATMEL based, both ARM architecture. Continue reading Time to get some experience with 32bit microcontrollers
One often sees enquiries by people trying to save the hex file made during the Arduino build process.
It is not trivial, as in their wisdom, Arduino hides these details, and builds the hex file in a randomly named temporary directory for each IDE which it deletes when the IDE is closed.
There are times when you may want to save the hex file, perhaps to load it without a bootloader or using a non-supported bootloader, Flashing LED driver using an ESC was just such a project. Continue reading Capturing the AVR hex file built by Arduino on Windows
This is a review of an inexpensive 8010F Chinese bang-bang thermostat that was purchased on eBay for around A$13 complete with thermistor sensor and postage.
Above is the front view of the thermostat. There are many thermostats on the market with similar front panels, but they differ in internals and most importantly, performance and quality.
Above, the rating label is clear and informational. It is rated at 10A for resistive loads (AC-1), but it is doubtful that AC-3 motor loads of more than 20-30% of that should be used. Continue reading Review of inexpensive Chinese thermostat – 8010F
I have described a solution an overheating problem with my IC2200H at Cooling an IC2200H.
Another solution for control of the fan to minimise nuisance draft and noise is one of the inexpensive digital thermostats on eBay.
I reviewed one of these things at Review of inexpensive Chinese thermostat – MH-1210. It had its issues, but as modified for 12VDC operation, I tested it for control of the fan in the above pic.
Above is the thermostat, though modified, purchased for about A$12 including post and the sensor thermistor. Don’t buy the MH-1210 as some at least are shipped with incorrect calibration. Continue reading Cooling an IC2200H – update #2
David, VK3IL, describes a small transmitting loop (STL) at Portable magnetic loop antenna.
At VK3IL’s 3m circumference LDF4-50B loop on 40m. I reviewed his loop behaviour on 40m, and its efficiency was quite low… though typical of a loop of that size at that frequency.
Radiation resistance of a STL is proportional to the fourth power of frequency, and since it is often dwarfed by loss resistance, we should expect that doubling frequency will dramatically improve performance.
As far as I can glean from the article, it is made from a 3m length of LDF4-50B Heliax, and uses a Patterson match to tune it.
David offered measurement of VSWR around centre frequency for the loop approximately matched (VSWR=1.24) on 20m. He has measured the VSWR=2.86 bandwidth shown between markers 2 and 3 to be 45kHz. Continue reading VK3IL’s 3m circumference LDF4-50B loop on 20m
This is a review of an inexpensive MH-1210 Chinese bang-bang thermostat that was purchased on eBay for around A$13 complete with thermistor sensor and postage.
Above is the thermostat. Note that the middle terminals, the 230VAC power input terminals are labelled ONLY in Chinese. It is rated at 10A for resistive loads (AC-1), but it is doubtful that AC-3 motor loads of more than 20-30% of that should be used. Continue reading Review of inexpensive Chinese thermostat – MH-1210
David, VK3IL, describes a small transmitting loop (STL) at Portable magnetic loop antenna.
As far as I can glean from the article, it is made from a 3m length of LDF4-50B Heliax, and uses a Patterson match to tune it.
David offered measurement of VSWR around centre frequency for the loop matched on 40m. He has measured the VSWR=2.6 (the half power) bandwidth shown between markers 2 and 3 to be 22kHz. Continue reading VK3IL’s 3m circumference LDF4-50B loop on 40m