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8 Oscilloscopes under €400 – Nut & Bolt – [via]
An oscilloscope is an essential tool when trying to understand what is going on inside your electronics. It is an expensive piece of kit: even a simple model costs several hundreds of euros/dollars. While it is possible to buy great second-hand analog oscilloscopes for a lot less, they are very bulky and don’t have the digital storage capabilities of modern oscilloscopes. In this post I’ll list the sub-€400 digital storage oscilloscopes I evaluated before purchasing one for Nut & Bolt.
8 Oscilloscopes under €400 reviewed - [Link]
Sergei Bezrukov writes:
A device for detecting toxic gases is a must in every household. This particularly concerns carbon monoxide (CO), as most private houses are equipped with furnaces burning natural gas for heat. Any blocking of the exhaust pipes (e.g. a squirrel in a pipe, or heavy snowfall in winter) might lead to poisoning with lethal outcome.
Commercial devices for detecting CO are priced about $30 – $100 and are generally much more expensive than the ones for detecting CO2. Most of them just detect some presence of CO and launch an alarm without indicating the CO level. Building a CO-meter by yourself is not much less expensive than the cheapest commercial devices of that kind if we consider just the cost of components and their shipping. This is not that bad if you are doing electronics and already have many of them, but the sensor itself costs about $14. However, you can completely control your own device, program the alarm threshold, and adjust it for your needs. It is also worth mentioning that building your own device is at least a $100 fun
Digital carbon monoxide (CO) meter - [Link]
diy.viktak.com writes:
The geek inside me has always wanted a fridge that shows the inside temperature for both the freezer and the fridge compartments. However, when we recently replaced our very old fridge we ended up getting a new one without the built in thermometer. So I decided that one of my next projects would have to rectify this problem.
Dual PIC Thermometer - [Link]
z097dsa writes:
This is a project for a Russian IN-13 bargraph Nixie tube to use it as an indoor room thermometer. It is named “NixieTherm” and is also available as a fully complete kit incl. enclosure as shown at www.Nixiekits.eu
The IN-13 is a special construct of a gas discharge Neon display and works similar to the well know Neon bulb in illuminated mains power switches or as Nixie tubes. But this bargraph has a current depending length of the glow. As all other cold discharge tubes also the IN-13 needs a “little bit more” high voltage to work; at least 120VDC. The current through the tube must be limited, normally with a resistor. In the NixieTherm this is done with a high voltage transistor, as we need a variable current from 0….4.5mA.
Analog IN-13 bargraph Nixie tube thermometer - [Link]
Sergei Bezrukov writes:
This is a shortened translation from Russian of my article published in Радио (Radio) magazine, no. 8 (2010) pp. 21-23. The voltmeter is designed for controlling DC voltages at the output of a dual bipolar power supply. It not a universal instrument, since its input resistance does not exceed 40K, which might be too low for some measurements. However, it is perfectly fine for power supplies and does not noticeably load their output. The range of input voltages is 0 to 24V for positive supply and -24V to 0 for negative one.
The voltages are sampled every 300 msec and displayed on a 9-digit LED display. Only 8 digits are used, the middle digit slot is always off and serves a a separator between negative (on the left part of display) and positive (on the right one) readings. The unit provides a 0.01V resolution. For small negative voltages (not exceeding 10V in absolute value) a leading minus sign is displayed. For positive voltages a leading zero is suppressed.
Voltmeter for bipolar power supplies - [Link]
Sergei Bezrukov writes:
This was my last weekend project, which I needed to complete urgently. The LC-meter design is based on a front-page article in Everyday Practical Electronics magazine, no. 3, 2010. A similar project is also published here. Assembled for a very occasional usage, I did not put it into a case.
LC meter - [Link]
Sergei Bezrukov writes:
This is a shortened translation from Russian of my article published in Радио (Radio) magazine, no. 12 (2009) pp. 18-21. The micro-ampermeter described here is intended for experimenting with low-power devices. I have just a general multi-meter in my home lab, which is not very convenient to use. The reason for this is that now-days many electronic devices have a power saving mode, where their current consumption drops down in 1-3 orders of magnitude. Measuring current in a device that periodically enters a sleep mode makes it necessary to frequently adjust the multi-meter range, unless it is automatic. Unfortunately, my multi-meter is not automatic. Moreover, I often need to measure current along with voltage, which makes working with my measuring device even more inconvenient.
The micro-ampermeter described here has the following features:
- Monitoring current range: 0.05μA – 10mA
- Four subranges: 0.05μA – 9.99μA, 10μA – 99.9μA, 100μA – 999μA, 1ma – 9.99mA, automatic range switching.
- Voltage drop: 82mV max
- Automatic shutdown after approx. 3 minutes of inactivity
- Battery operation from 2xAAA batteries, average drawing current 10mA
Automatic micro-ampermeter - [Link]
Sergei Bezrukov writes:
This project is based on the Function Generator described on Mondo Technology web site. I just did very slight changes and fixed some obvious typos in schematic. The code is rewritten for the Microchip MPLAB IDE syntax.
Device features
- Frequency range: 11Hz – 60KHz
- Digital frequency adjustment with 3 different steps
- Signal forms: sine, triangle, square, pulses, burst, sweep, noise
- Output range: ±15V for sine and triangle, 0-5V for others
- Sync output for pulses
The device is powered from 12VAC which provides a sufficiently high (over 18V) DC voltage needed for a normal operation of 78L15 and 79L15. The 12V power supplies are replaced with 15V ones. This is done in order to LF353 Op-amp could output the full range of signals to a 1K load. By using a ±12V supply this resistor must be at least 3K.
60kHz PIC Function Generator - [Link]
Sergei Bezrukov writes:
My goal was to design a simple and user-friendly frequency counter which would be capable to handle radio FM frequencies and have an autonomous power supply. Powering it from batteries benefits to the device portability and makes working with it more convenient by eliminating a mess of power cords in a home lab. I use it just occasionally and a small size is a bonus simplifying its storage in a table drawer.
Most of similar devices I have found on the Internet use an LCD module with a built-in controller. Such a device draws pretty much current. Also, many high-speed counters use power-hungry ICs which makes it difficult for a battery operation. Finally, many projects are poorly documented which makes any modification unnecessary difficult. So, I started my own design which uses modern high speed and low-power ICs and can work from a single AA cell.
150MHz PIC Frequency Counter - [Link]
Fast Frequency Counter - [Link]
Test Thyristor and Triac using this circuit. Pay attention on mains voltage!
Thyristor – Triac Tester - [Link]
