300 mm DRO with Arduino (ATTiny85 and Nano)

In this video I show you a nice DRO with a great range (300 mm) and good resolution (0.01 mm).

I “hacked” the DRO and was able to hijack its data and clock signal and convert it into human readable values using an ATTiny85 microcontroller. I made my own tiny display unit for this DRO and the principles I used is applicable to similar DROs and digital calipers as well as any Arduino-compatible microcontrollers.

If you want to buy the things I used in the video and support me at the same time, please consider using my affiliate links on my website:

[CuriousScientist]

Hey! Please make sure you check my website (link is in the description)! I did some improvements to the code and I also uploaded a "pure" Arduino code that you can directly upload to a Nano or Uno without any modifications. Cheers!

[Tensquaremetreworkshop]

Excellent information, this has saved me considerable time on my current project. One small point- your code line 'convertedValue += (pow(2, i) * dro_bits[i]);' is incredibly computation intensive- and repeated 19 times. Bit-shifting is simpler, and assembling in a long (actually, 300mm only needs an int) before moving to a float will save considerable time. For scales under 600mm, only reading 16 bits, and bit shifting during reading [if (digitalRead(data) (unsigned int)rawData += (1 << i);] (aligning i will be required) will reduce final computation to an int to float conversion- and reduce storage. All this may become important if the Arduino has other things to do- which mine will. Thanks again for your efforts.

[vancehines]

Excellent Video. around 6:00 6 Nibbles = 3 Bytes = 24 bits.

[isidoromaich]

Amazing project! Great work you've done here. In the past I was watching the caliper2pc project but it never ended up to convinced me. I will be watching how this evolve.

[mousam_upadhyaya]

Excellent thorough tutorial, I like the pace of tutorial and 15:28 - Nice lines 😃

[markmaker]

Great tutorial and explanation of how everything works, thank you!

[jtreg]

Hi there, do you have Frizing diagram for the Nano circuit? I looked for it on your blog, only saw the one you did for ATTiny... but really nice video thank you!

[jamesan]

I enjoyed your tutorial on the 300mm DRO. I do not see any level change cct, from 3.3V to 5V. I have adapted the cct. and sketch to Arduino Nano but clk and data signals are too low to trigger inputs without level changing. Could you explain how you get the Nano to work without level changing. Thanks.

[mrdebug]

nice & proper work + explanation 👌🏻 I only miss thy sync with the pause in the CLK signals to start at beginning of the 24 bits...
maybe this was the binking the display in your Demo?

[rbgohome]

I am totally new to electronics, but working with 3D printers and laser engravers raised the wondering about how it all works.
Already dreaming of creating my own tough and precise CNC milling machine; one of the concerns is precision of linear motion system for XYZ.
Does the number of steps of a stepper motor, exactly results in the target position?
Does the advances per step during a full stepper motor rotation, fluctuates?
Already saw how to drive stepper motors with Arduino. Combined with your greatly appreciated information,
allows to drive a stepper motor, capture the data stream of a DRO, and produce graphs/statistics about precision of the motion system and or components used.
I will make time for this before the summer. Thank you for sharing this.

[petercohen]

Hello, thanks for the excellent video. Have you found out the reason for those strange incorrect readings and fixed the problem in the "pure" Arduino code?

[negvorsa]

I think the waiting for the start condition code is not correct, you may fall into the middle of any other falling edges ...

[milanercegovic]

Hello how are you. Videos are great to watch and well explained from start to finsh. I would like to install rotary encoder wirh a shaft directlly to lead or ball screw to achieve DRO insted magnetic or glass scale connected to a Bluetooth TouchDRO. Can it be done. Thank you.

[puneethpoduri]

I can hear a low frequency hum like a motor running. can anyone else hear that?