Arduino Data Glasses for My Multimeter

147,199

1,649

164

Posted

Introduction: Arduino Data Glasses for My Multimeter

Grand Prize in the
Epilog Contest 8

Second Prize in the
Arduino Contest 2016

Video of the working device

Trying to build a cheap Arduino Data Glasses for everybody. Why? I just wanted one.

It's working, and now it can even help to avoid accidents. From the first idea to the working prototype, it took 4 Month

The challenge was, that It should be constructed out of common materials that can be found easily. The project is more about how to build the optical system for this HMD. One thing is clear, you can not just place a screen in front of your eyes, because it will not be possible for them to focus it.

In the logs you can see from the first tests to what I have now.

The optical design was the most difficult part, but I think I found a solution for this. The costs of the prototype amounted to +-70Euros.

And now I have a Head-Up Display For Hight Voltage

Step 1: What's Inside and How Does It Work?

The received Bluetooth data is displayed, on the OLED display. It's then reflected over the mirror, goes through the lens and you can see the picture in the little transparent acrylic glass.

That is the simple explication. The details are coming now :)

Step 2: The Lens. the Most Tricky Part

I made the data glasses work, but it was more a trial an error challenge.

So I took a google crash course in optics.

First of all I had to understand the difference between a real and a virtual image with lenses. Then a very important thing is, that a human eye can only focus an object at a distance of min 25cm. And all what I needed was this formula (1/f) = (1/o) + (1/i) where f is focal length of the lens o is object distance to the lens and i is the distance of the virtual image.

Here are the values I used:

with f=10cm and o=7.3cm

you will get an i=-27.03cm (virtual images have always a negative value) and a magnification M=3.7

Lens Calculation Website
http://hyperphysics.phy-astr.gsu.edu/hbase/geoopt/image4.html

Step 3: Alternative Lens

I know that the lens is hard to find. I uses one of a cheap cardboard wich has lenses with a Focal length of 100mm and not like the google cardboard 45mm

UPDATE

I think I found a good solution for the lens. I just checked the physical data (FL = +- 110mm). and they should be perfect. I have no time right now, to test them, but if somebody could do it and give me a feedback, this would be great. A small Fresnel lens should do the job. and they are cheap and easy to find on the internet. And you can cut them with a cutter.

Like this one https://www.amazon.com/Small-Fresnel-Lens-Magnifier-Pack/dp/B00CF5ZXKK

An otherf alternative is a the lens of a head mounted magnifier. Normally they deliver 3 to 5 lenses and one of these should have a FL between 110mm and 120mm which works fine. It's just a little bit heavier and not so easy to cut

Step 4: Electronics

Here are all the electronic parts for the data glasses

I just used a smaller battery in the final version.

To use the 280mA battery, I had to change the 3k resistor against a 5.6k resistor on the original board. The charging current is now reduced to +- 200mA.

Step 5: the Enclosure

For the first tests, I used an enclosure made out of cardboard. This was a cheap solution and worked very well

For the final version, I used my 3D printer. The style file has been created in 123design. I need to make a few modifications to the design, but it's not bad for the first try.

Step 6: Connecting the Owon B35T Multimeter With the Data Glasses

This multimeter has an intern bluetooth 4.0 communication, so you can connect it to your phone or tablet

I had to reverse engineer the serial protocol.

Config of the BT module. I used a simple Arduino program to send and receive Data to and from the module. First you have to set the module to Central.

AT+ROLE1 moule = central

AT+RESET reset AT+SHOW1 show Bluetooth name in response

AT+IMME0 connect automatically

AT+FILT0 scan for devices

AT+DISC? Show devices

To connect to the Owon B35T type AT+CONE0(Mac adress of the Multimeter)

These softwares can be found on github https://github.com/awall9999/Arduino-Glass

Videolink to the bluetooth test

Step 7: The Final Arduino Data Glasses

Here you can see, how all the parts fit in the enclosure. I tried different holders for the acrylic reflector

Here is also a part list:

Link to the software on github

Link to all the videos on youtube

Step 8: Pictures and Videos of the First Steps

Test setup with different lenses

First bluetooth test video

One of the prototypes video

Things to do:

  • Finishing the Software, to auto connect to a Owon Multimeter
  • Adding a battery indicator in the display. (The BLE module has this feature)
  • Building different reflectors with tint and mirror foils, to make the glasses work in a bright area,
  • Reducing the weight and redesigning the enclosure.
  • Testing with a smaller 0.49 inch display.

Share

Recommendations

  • Remote Control Contest 2017

    Remote Control Contest 2017
  • Arduino Contest 2017

    Arduino Contest 2017
  • LED Contest 2017

    LED Contest 2017

We have a be nice policy.
Please be positive and constructive.

Tips

Questions & Answers

160 Comments

Very cool! The number of times I've needed a third hand to hold my meter!

Sadly my old meter (Fluke 79) was made before Bluetooth was even a twinkle!

Could someone send the cardboard templates?

Great project!

I just wanted to pass on a good source of inexpensive lenses of all types, as well as beam splitter mirrors that transmit 50/50 (for a brighter image than plain acrylic). Go to surplusshed. com, they have hundreds of lens types you can browse, or use the lens finder if you know what you're looking for. A lens similar to the one in this project (double convex, 19mm diameter, 10.8cm focal length) is item L14219 for $4.50.

They have various types of plate beam splitters for next to nothing.

Also it's just a good place for optics, electronics, robotics parts--all kinds of miscellaneous surplus stuff for cheap. No connection with them, just a satisfied customer.

Noice. Looks like a fun project.

Amazing project! Congratulations.

Congradulation! So cool and usefull

Thanks for sharing

Thumbs up on this one mate such intuitive use of OTS components. RESPECT!

How clever! I’ve often contemplated doing this with my welder. I’d like it to read out the amperage of the weld to a heads up display in my welding helmet in real time so I know exactly how much current I’m giving it with the foot pedal.

Amazing achievement! Thank you.