Cliff knobs – a pleasure to touch


In our portfolio can be found quality knobs from company Cliff suitable for a wide range of potentiometers and encoders.

A device with excellent specification, quality components used, …., but a one step is still missing to reach a great overall impression – it is to use a quality and aesthetic control components.

Probably you´ll agree, that knobs for potentiometers and encoders belong to a “group of critical components”, determining a resulting look of a device. Company Cliff specializes on development and production of these components already from 1977 and considerable experience are reflected in a precise construction and a wide portfolio of components produced.

Directly from our stock, we´re able to offer you a few interesting series:

  • K87MAR – plastic two-color knob with a colored top part and a side line. Available in 8 standard color versions. Thanks to a big popularity and a mass production, their price is very affordable. User friendly, soft – “rubber-feel” surface. Excellent for color coding of potentiometers groups in equipment with many knobs. 6mm „D“ shaft.
  • K87MBR – plastic two-color knob, very similar to series K87MAR, but only a side line is in color. Affordable price and a mild “rubber-feel” surface. 6mm splined shaft or 6 mm “D” shaft.
  • K18 – universal plastic knob for electronic encoders. Available in 5 colors and 3 weight categories. In our stock can be found 2 heavier versions (35 and 50g) in a grey and black color.
  • KMK – universal aluminium knob with a machined aluminium shell and a molded plastic inner. Available in a black or natural anodized surface. Push-on installation. In our stock can be found 4 versions with a 25 mm diameter – KMK25 in a black and silver (natural) color, with a 6mm splined as well as “D” shaft.

Types for splined arbors have 3 relatively robust juts (as visible on a Picture), that´s why they´re suitable only for potentiometers with deeper splines, or with a lower splin count. From our offer they´re suitable for example for Taiwan-Alpha potentiometers and they´re not suitable for potentiometers Piher series PC16.

Further information will provide you the K87MAR, K87MBR, K18 and KMK datasheets. Upon request, we´re able to deliver you more types from the portfolio of Cliff knobs.

Cliff knobs – a pleasure to touch – [Link]

Basic Temperature Control for Refrigerators

This design is a basic temperature control for refrigerators that has an electromechanical circuit. It specifically uses MC9RS08KA4CWJR microcontroller which has an 8-bit RS08 central processing unit, 254 bytes RAM, 8Kbytes flash, two 8-bit modulo timers, 2-channel 16-bit Timer/PWM, inter-integrated circuit BUS module, keyboard interrupt, and analog comparator. This project effectively controls temperature of any device using resistors and capacitors.

The refrigerator temperature control is a basic RC network connected to an I/O pin. A variable resistor (potentiometer) is used to modify the time the capacitor takes to reach VIH and adjusting its resistance varies that time. A basic voltage divider with one resistor and one thermistor is used to implement the temperature sensor. The thermistor resistance depends on the temperature. For each temperature, we have a different voltage in the divider. This value is effectively measured with the Analog-to-Digital Converter (ADC) implemented by software that uses one resistor, one capacitor, and the analog comparator. In addition, VDD and VSS are the primary power supply pins for the MCU. This voltage source supplies power to all I/O buffer circuitry and to an internal voltage regulator. The internal voltage regulator provides a regulated lower-voltage source to the CPU and other MCU internal circuitry.

This temperature control will not only be applicable to refrigerators but also to electronic devices that need temperature monitoring. It is a low cost device that may be integrated to appliances, medical and industrial equipment.

Basic Temperature Control for Refrigerators – [Link]

The Art of Representing Floating-Point Numbers as Integers


Mário Ribeiro writes:

Have you been using float or double variables to perform mathematical operations on embedded systems without a Floating-Point Unit (FPU)? You are doing it wrong! That’s incredibly inefficient.

An FPU is an hardware block specially designed to carry on arithmetic operations on floating point numbers. Even though the C/C++ code may work without an FPU, it’s always much faster to use hardware designed for a specific purpose, like this one, instead of relying on a software implementation, something that the compiler will do for you, knowing the hardware restrictions you have but not in an efficient manner. Essentially, it will generate a lot of assembly code, greatly increasing the size of your program and the amount of time required to complete the operation. Thus, if you don’t have an FPU available and you still want to perform those arithmetic operations efficiently you’ll have to convert those numbers to fixed-point representation. Integers! But how? By scaling them. Let’s see how that scaling value may be determined.

The Art of Representing Floating-Point Numbers as Integers – [Link]


DIY soldering station


MatthiasW over at DebuggingLab posted his DIY Weller station clone project, that is available at Github:

At the Forum I read about a DIY Weller station. Basically an Arduino shield to drive a Weller soldering tip. As there is not much to it, the board simply contains an precision OpAmp, a power MOSFET, 2 buttons for adjusting the temperature and a display to show the current values. This design looks like a good starting point for my own advanced project. As I have lately discovered a 1,8 inch SPI TFT at for an amazing price ( ~ 4.60 $ / 3,70 €), I started using them regularly in my projects. So I surely wanted to use it with this soldering station as well.

DIY soldering station – [Link]

LiTiny- A Tiny LiIon charger for most things battery


Rohit Gupta made this LiTiny project, a tiny LiIon charger:

In the end I had a LiIon charger capable of charging batteries @700mA restricted due to thermal dissipation limits of home made PCBs.

LiTiny- A Tiny LiIon charger for most things battery – [Link]

ESP8266 WiFi Shield for Arduino and other micros


by drmpf @

This ESP8266-01 WiFi Shield is an alternative to the Very Cheap/Simple Wifi Shield for Arduino and other micros. The Very Cheap/Simple Wifi Shield for Arduino and other micros uses an Adafruit HUZZAH ESP8266 module and is the simplest to wire up. However if you already have an ESP8266 module, you can use these instructions to make a WiFi Shield using it.

This instructable uses the ESP8266-01 module, if you have one of the other ESP8266 bare modules, provided the module has GPIO0 and GPIO2 available, then you can use these instructions. If the module makes GPIO15 accessible YOU MUST connect it to GND via a resistor with a value between 3K3 and 10K.

ESP8266 WiFi Shield for Arduino and other micros – [Link]

Unipolar 4-Phase Stepper Motor Controller


Unipolar 4-Phase Stepper Motor Controller Board will help you control a Stepper Motor or 4 individual Solenoids. This circuit consisting of transistors that serve as current amplifier and also diode to prevent damaging back EMF, circuit uses Darlington transistors to provide high current capacity to unipolar stepper motor. Just provide sequence of pulse using Micro-Controller or descript circuit to roll out the unipolar motor. On board High Watt resistor to control the current, value of the resistor can be set as per your load current requirement.

Unipolar 4-Phase Stepper Motor Controller – [Link]

EAGLE BOM generation script

bom-gen_001Dilshan Jayakody writes [via]:

This is a quick post about EAGLE parts list generation script which I was written to replace existing “part2html.ulp”. This script generates more organized and detailed BOM HTML file and it can directly replace “part2html.ulp”.

This script is tested with EAGLE 6.6.0, but it can also work with older versions of EAGLE software.
This script is available to download at github with usage details.

EAGLE BOM generation script – [Link]

How to use an LCD displays – Arduino Tutorial


by codebender_cc @

The LiquidCrystal library allows you to control LCD displays that are compatible with the Hitachi HD44780 driver. There are many of them out there, and you can usually find them by the 16-pin interface.

In this tutorial you will learn how to use LCD 16×2 display (and 20×4) with Arduino uno.

You will also learn how to use lcd.begin(), lcd.print() and lcd.setCursor() functions

How to use an LCD displays – Arduino Tutorial – [Link]