I am a software engineer and have limited experience with conventional circuitry. Recently, I have built a prototype device that uses an Arduino Uno, a Bluetooth module, an array of temperature/humidity sensors, and an OLED readout display, which currently relies on I2C. The function of my device is to simply wait to receive a BT signal, which wakes it from low power, then enables data acquisition by the temp. sensors for a fixed length of time while averaging at each read interval, and then displaying the averaged temp. & humid values on the OLED.

Ultimately, I am trying to determine if can move away from the ATmega328p chip and design a MCU-less circuit with conventional electronics for a production model. My project objectives motivating this idea are: achieving lower material and labor costs and eliminating the dependence on software and firmware. Both are equally important to me. However, I do not know if I am creating other substantial obstacles for myself in doing so. How can I determine 1) if what I’m asking is even possible to do given the functional requirements of my device and 2) if it’s the right choice going the MCU-less approach based off my project objectives?

  • 3
    \$\begingroup\$ MCUs are being pretty conventional for decades. Anyway, having BT implies a usage of some MCU anyway. You can get some better suited MCU with integrated BT though for your purposes. \$\endgroup\$
    – Eugene Sh.
    Mar 9, 2021 at 22:56
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    \$\begingroup\$ Might have misunderstood the requirements but what you describe without MCU/etc sounds practically unfeasible. I mean, you need I2C, Bluetooth, low power/sleep, etc right? \$\endgroup\$
    – Wesley Lee
    Mar 9, 2021 at 23:01
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    \$\begingroup\$ OLED display, BT and so on are going to require either an MCU or equivalent implemented in some (extremely complex) manner. Forget about MCU-less and choose which MCU. \$\endgroup\$ Mar 9, 2021 at 23:10
  • \$\begingroup\$ If the task has multiple disparate steps, go MCU. Your entire first paragraph = multiple disparate steps. \$\endgroup\$
    – DKNguyen
    Mar 9, 2021 at 23:48
  • \$\begingroup\$ $1 Pic uC can do this. \$\endgroup\$ Mar 9, 2021 at 23:49

1 Answer 1


Yes, you could reduce the part count by getting an IC that has bluetooth and a microcontroller in on IC (there are some to look at here) which are becoming more prevalent on the market right now.

It wouldn't be a MCU-less circuit necessarily because the MCU and the bluetooth module would be combined.

  • \$\begingroup\$ With BT is there no real way of integrating it without some sort of MCU. I am quite unfamiliar with the inner workings of BT. Maybe worth some time to understand... \$\endgroup\$
    – Bryan A.
    Mar 10, 2021 at 1:19
  • \$\begingroup\$ The modules make it easy in many cases with AT commands instead of needing to write software \$\endgroup\$
    – Voltage Spike
    Mar 10, 2021 at 2:20
  • \$\begingroup\$ @VoltageSpike I think you may have a mistranslation or an auto-correct mistake in your comment \$\endgroup\$
    – user253751
    Mar 10, 2021 at 13:07
  • \$\begingroup\$ Woah, yeah, that is not what I intended! You never know what your phone is going to throw out when you use voice commands! I missed it because there was another error that I corrected, definitely editing that comment \$\endgroup\$
    – Voltage Spike
    Mar 10, 2021 at 16:06

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