Planet Arduino

Measuring voltage with a multimeter is easy enough, and current is a bit harder, but reading both values simultaneously can be a challenge. If you’re tired of having to replug or find two meters, then look no further than Karl Kristian Torp’s palm-sized Tiny V/A. 

His Arduino Nano-based unit takes input from a power supply via a female barrel jack connector. This supplies the load through a male connector output, and also powers the Arduino, an IN219 sensor, and a 0.96” OLED display. Everything is housed inside a 3D-printed case.

A single capacitive touch buttons allows you to easily navigate Tiny V/A’s menu and change settings like sensor range and refresh rate. Additionally, it can even powered over USB as needed for an expanded voltage range.

More details on the project are available in Torp’s Instructables post.

If you ever wondered about building your own multimeter, YouTuber Electronoobs shows us just how to do so with an Arduino Nano.

Aside from the Nano, he’s using a 128×64 OLED screen to display stats and battery level, and a 16-bit ADC for precise measurements. Power is provided by a small onboard LiPo battery, and he’s even included a charging module to help keep things topped off. Everything is housed inside a custom 3D-printed case. 

The device doesn’t just measure voltage, resistance, and current, but is capable of reading capacitance and inductance as well—measurements that you wouldn’t necessarily expect on a commercial meter. If you’d like to create your own, the schematic and code are available on Electronoobs’ site.

Raj @ embedded-lab.com writes:

Here is an instructable that describes a DIY shield which would convert your Arduino board into a multifunctional digital multimeter. This shield can be used with “Arduino” UNO und Duemilanove boards, and can display the measurements on a 16X2 character LCD and/or on the serial monitor window on PC. This digital multimeter Arduino shield has the following features:voltmeter ranges : 0-10V; 0-30V; 0-100V ampmeter range : 0-500mA ohmmeter ranges : 0-1KOhm, 0-250KOhm diode, LED, continuity tester LED functionality tester transistor Beta meter.

Turn your Arduino board into a digital multimeter with this shield - [Link]

You can’t argue that Arduinos are extremely popular with the maker/hacker community. Some would say that there is certainly no shortage of projects to make using them. [Milen] thought otherwise and felt it was time to create an Arduino-based multimeter.

At the heart of this project  is a common Arduino Uno. The additional parts were kept to a minimum in order to keep down the overall cost and project complexity. The finished product can measure voltage from 0-100v, amperage up to 500mA and resistance between 0-250 kohm. If you need to check for continuity, it can do that too.

All of the parts required to make the multimeter fit on a shield that plugs directly into the Arduino. Banana plugs allow for attaching test leads. The measurement values are displayed on an LCD screen and/or (if connected) to the Arduino IDE Serial Monitor. If only using the serial monitor, the LCD screen can be omitted to save a few bucks.

If you would like to build one for yourself, the above link has detailed instructions, schematics and a bill of material. The best bang-for-the-buck multimeter available is still the Harbor Freight Special that you can usually get for free with purchase.

[Thanks Karl]

This Instructable will teach you how to use the Arduino Analog ports. johnag @ instructables.com writes:

Digital Voltmeters (DVMs) are a special case of Analog to Digital converters- A/DCs.- they measure voltage – and are usually a function of a general purpose instrument called a Digital Multimeter( DMMs), commonly used to measure voltages in labs and in the field. DMMs display the measured voltage using LCDs or LEDs to display the result in a floating point format. They are an instrument of choice for voltage measurements in all kinds of situations. This instructable will show you how to use the Arduino as a DC DVM (Direct Current Digital Volt Meter).

Make a Mini Arduino programmable 4 channel DC-DVM - [Link]

In this review we examine the new Agilent U1177A infra-red to Bluetooth adaptor for the Agilent  U1272A DMM. You can also use the adaptor with the U1240-series DMMs with the optional adaptor. With some PC or Android device software you can monitor or log data from up to three DMMs. So let’s have a look and see what it’s all about.

Introduction

The adaptor arrives in a small box:

… with the following contents:

It was a relief to see the AAA cells included as we didn’t have any in stock. The yellow document is the China RoHS sheet, and the instructions are short but well detailed. The unit itself is quite small:

To fit the battery or reset the device, the front cover slides open revealing the innards to some degree:

and the rear:

The unit clips soundly to the rear of the DMM, however it does stick out quite a lot:

If you need to leave the meter unattended, you’ll need a level and vibration free surface, as the adaptor can be knocked out relatively easily from the top. The adaptor also blocks the hole at the back which some users may use with a hook or loop for positioning the DMM.

Software and Operation

You can use the U1177 with two platforms – Android and Windows, and we tested both. I’m sure if you have Mac Parallels, etc., that there may be some success there but I haven’t tested them. There are two applications available for Android devices – the mobile logger and mobile meter. You can download them both from the Google Play app – just search for ‘agilent‘, and the results should be

The third app is a game that is somewhat entertaining. We tried the applications on two Android devices – a HTC Velocity running Android 4.0.3 (which failed miserably, the software kept freezing) and a Motorola Xoom MZ601 with Android 3.2. I would say now that the software is marked “Beta” so caveat emptor. The data logging software worked on the Xoom but not the “Agilent Mobile Meter”. Moving forward, the logging software is quite good – you can display a graph, table or statistical value of the incoming data from up to three separate DMMs.

Below is a rough video of using the Xoom with data logging. We first make the Bluetooth connection, then measure resistance of a 1k ohm logarithmic pot, change the view to data table, then stop the logging and email the data. The app can email a .csv file which can be opened with any spreadsheet, etc. Using the app you can label each DMM feed to avoid confusion with the data files in the future.

Using the U1177A with a Windows 7 x64 machine was a lot more successful. You can download the Windows-based software from here (97 MB). After pairing the adaptor with the bluetooth connection software, the Agilent software loads but does not connect. You need to alter the data speed to 19200bps and select the COM port from the drop-down list in the “communication settings” on the left-hand side of the window, as shown below:

You can also use terminal software and AT commands to change the parameters of the U1177A, which is described in the user manual. Moving forward, once connected you can measure and log to your heart’s content. You can display a virtual meter:

Or choose a graphing display mode:

Note the short drop in value to zero as the graph increased on the far-right of the measurement in the image above. This occurs when the meter is changing range, just as the LCD will blink off then on due to the same phenomenon. Finally, you can also display the data as a table, for example:

Finally, you can export the data to a .csv file which can be opened with the usual spreadsheet or text editing software:

Using Windows OS Remote Multimeter Use Data Logging Other connection – hyperterminal etc. 

Conclusion

For data logging to a PC that is in Bluetooth range, the U1177A fits the bill. Although you can get a serial to IR cable (and early U1272A owners should have received one when the firmware update was released), the Bluetooth module will certainly be useful when moving around a worksite, or taking remote measurements from extreme temperature or NVH environments. The Android apps need to move out of beta stage – however due to the variety of devices and OS versions in the market this may be a long journey. However considering the price (~Au$52) it is inexpensive enough to keep around just-in-case.

Note – the U1177A was purchased by myself and reviewed without notice. Residing in Australia, ours was purchased from element14.com.

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