Archive for 2010

Uni-Trend UT81B Review

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I was looking for a decent handheld oscilloscope/meter and eventually ended up buying the UT81B from Uni-Trend. There isn’t much information available about this model so I decided to do a small review of it.

Let’s start with some basic specifications from the manufacturer:

  • 8MHz bandwidth
  • 40MS/s sample rate
  • adjustable trigger (level and slope) with single-shot mode
  • voltage, current, resistance, capacitance and frequency measurement
  • 10 screen memory
  • 160×160 monochrome display with backlight
  • USB connection

Specs seem quite good for a handheld device and it should accurately display signals up to 4MHz. Time to check it out!

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PIC Countdown Timer


This project is intended as a countdown timer for a UV exposure box for PCB development that uses fluorescent UV lamps (it will also work with any other lamp, don’t worry). It is based around a PIC16F627 micro and has following features:

  • adjustable time in 15-second increments (up to 10 minutes)
  • lamp preheat feature
  • two button operation (with audible feedback)
  • countdown alarm (when timer reaches zero)
  • relay for lamp switching
  • 7-segment display

10 minutes?

I have chosen the upper time limit of 10 minutes which should be more than enough for most applications and initial time is set for a 5 minute countdown (I’m preparing a revised software which will load initial time from EEPROM so it can be configured manually). Step increment of 15 seconds has been chosen partially due to ease of operation because there are only two buttons – time adjustment and start/stop. Time adjustment is incremental meaning that each time you press the button time is incremented by 15 seconds. When upper limit is reached time is reset to zero and the process repeats. Start/stop button is used for, you will never guess, starting and stopping the timer with lamp preheat feature.

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Hello world!


Welcome to Arc’s Lab!

As you can probably notice the site is pretty much useless at the moment since I just started it.


Here I will present my own electronics projects/circuits and provide all the schematics and instructions required to build them. You can also expect to find some random posts mostly related to electronics as well as component tests and small circuits which have extensive applications in other projects.


As soon as possible! I already have some cool projects for you, just be patient until I write something meaningful.

For whom?

Mostly for semi-experienced people interested in electronic and DIY. I will assume you know some basic theory and have skills necessary to etch your own PCBs and solder components in place.


In plain english and without much fuss! Expect some gramatical and spelling errors since english is not my native language.

“See” you soon!


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