CG K/ J/ S/ B to 4-20mA 0-1800 Celsius Thermocouple Converter TC Input 4-20mA Output Head-mounted Temperature Transducer – first impressions

CG K/ J/ S/ B to 4-20mA 0-1800 Celsius Thermocouple Converter TC Input 4-20mA Output Head-mounted Temperature Transducer.

So the concept is that one can program the transducer module for a range of input sensors, and lower and upper limits to the conversion range. Another significant benefit is that it does cold junction compensation (and it does not seem possible to disable it if you wanted).. Continue reading CG K/ J/ S/ B to 4-20mA 0-1800 Celsius Thermocouple Converter TC Input 4-20mA Output Head-mounted Temperature Transducer – first impressions

EARU Programmable Thermocouple K J PT100 to 4-20mA Converter TC RTD Input 4-20mA Output Head-mounted Temperature Transducer – first impressions

This article is a review of the EARU Programmable Thermocouple K J PT100 to 4-20mA Converter TC RTD Input 4-20mA Output Head-mounted Temperature Transducer.

So the concept is that one can program the transducer module for a range of input sensors, and lower and upper limits to the conversion range. Another significant benefit is that it does cold junction compensation (and it does not seem possible to disable it if you wanted). The stated cold junction compensation range is narrow at 20-60°, it seems unlikely but bears testing. Continue reading EARU Programmable Thermocouple K J PT100 to 4-20mA Converter TC RTD Input 4-20mA Output Head-mounted Temperature Transducer – first impressions

Making a jtag2updi adapter

This article is about selection and reprogramming of an adapter to make a jtag2updi adapter using the code published at https://github.com/ElTangas/jtag2updi.

The purpose is for programming some of the newer AVR chips that use UPDI.

Above is a JTAG ICE that I purchased, but I did not check the pics carefully enough and fell foul of the Chinese Cheats. The chip arrowed is the USB-RS232TTL chip, it is a PL2303HX which will not work in Windows 10 since the driver was poisoned many years ago. Continue reading Making a jtag2updi adapter

SNTP synchronised clock v0.04 – beta release

The SNTP synchronised clock (ssc) is an ESP8266 based time of day clock with an LED display.

Above are two prototypes both using HT16K33 display modules. (The display has a blinking colon, it is off in the pic.) There is a silicon photo transistor just above the display, used to sense day/night and the firmware changes display brightness. Continue reading SNTP synchronised clock v0.04 – beta release

Chinese 9.6V 700mAh Tamiya style battery pack

I had need for a rechargeable 9.6V NiMHbattery to replace a worn out one.

The last was made by fabricating a pack with AA long life cells and it worked well for 10 years… but its time had come.

The above pack on eBay for $12 ($17/Ah) looked interesting, though it would need a wrap of heavier heatshrink. Continue reading Chinese 9.6V 700mAh Tamiya style battery pack

Chinese 3.0V 16340 CR2 Lithium Ion batteries

I had need for a rechargeable CR2 battery. The ‘standard’ CR2 is a non-rechargeable Lithium battery of nominal 3.0V.

I purchased two Ultrafire batteries advertised on eBay as Lithium-ion of 800mAh for $20. Without further qualification, we normally take Lithium Ion to be nominally 3.6V. The batteries are marked Li-ion 3.0V. Continue reading Chinese 3.0V 16340 CR2 Lithium Ion batteries

ESP WiFi relay project – update #1

ESP WiFi relay project – preview previewed a WiFi controllable relay board using commonly available low cost hardware from sources like eBay and Aliexpress.

The stimulus for the project is a remotely WiFi controllable relay for reset function in a remote controlled ham station, basically to recover operation of some system element by bouncing the power.

The information presented here applies to development v0.2.

Features:

  • support typical multi channel relay boards;
  • ESP8266 and ESP32 firmware versions;
  • WiFi credentials programmable via a captive web interface;
  • DHCP or static IP;
  • mDNS responder;
  • flexible configuration stored as json file in on-board LittleFS file system;
  • optional authentication to secure remote access.

 

Above is a ESP12F_Relay_30A X2_V1.1 relay board (~$20 inc shipping) deployed for field testing. This board has a switched mode power supply on board and will run on 7-28VDC. In this application, the AC circuit is wired through the NC contacts, and the relays are operated to break the power. Normal operation is with the relays released, and current consumption @ 13.8V is 30mA. Continue reading ESP WiFi relay project – update #1

WriteOptiBoot.bat

I have lots of projects across a range of microcontroller architectures where reliably programming a new instance of the target is required.

Using an IDE to compile and load, eg traditional / common use of the Arduino IDE, is not a path to that reliability.

A better approach is to save compiled binaries, and have a saved method of programming the chip, binary application code, EEPROM if needed, and hardware settings such as fuse bits, options etc.

Let’s look at an example,  a cmd file or bat file to program certain Arduino architecture boards with a customised Optiboot bootloader. Continue reading WriteOptiBoot.bat

ESP WiFi relay project – preview

The impetus behind the project is a remotely WiFi controllable relay for reset function in a remote controlled ham station.

The information presented here applies to development v0.1.

Features:

  • support typical multi channel relay boards;
  • ESP8266 and ESP32 firmware versions;
  • WiFi credentials programmable via a captive web interface;
  • DHCP or static IP;
  • nMDNS responder;
  • flexible configuration stored as json file in on-board LittleFS file system;
  • optional authentication to secure remote access.

A variety of integrated relay boards

Above, a Yunshan relay, not recommended as RESET pin is tied high. This one was binned, quite a waste of money. It exemplifies a common problem in that the RESET line is often not available on a header pin, this one is worse in having tied RESET high and no header pin for EN. Continue reading ESP WiFi relay project – preview