I want to be able to dim a led strip with a MCP41100 but I have no idea how to connect the digipot to the led strip...

It is connected to an ESP8266. I will have to figure out how to address the digipot from the ESP8266.

Here is the datasheet

  • \$\begingroup\$ This isn't a very good approach for dimming LEDs, as you're unlikely to get very good linearity just by varying the resistance between your power source and the LEDs. Also, your pot is likely to get very hot if your strip's high power. You could use it in the feedback loop of a switch-mode constant current regulator, which might work well, but is a fairly difficult circuit. The best approach, however, is probably to use PWM, which would probably end up being quite similar to the project described here. \$\endgroup\$
    – Jules
    Sep 10 '17 at 11:53
  • 1
    \$\begingroup\$ So you mean that I only need a MOSFET? What am I going to do with those MCP41100 then? :p \$\endgroup\$
    – Kaymaz
    Sep 10 '17 at 19:09

There are two primary methods of LED strip brightness control (that I know of)... PWM (as mentioned by Jules) and current control. Voltage control is not much use (e.g. using a digital pot as a voltage divider), as the gradient between the LEDs being 'off' and 'on' is so steep, and one also needs to be mindful of how much power is dissipated in the resistor.

A digital pot is redundant if you go the PWM route.

For current control, a digital pot can indeed be used to control the brightness of the strip at the service of a microcontroller. e.g wifi control message > microcontroller > digital pot > dimmer circuit > LED strip.

Current-control LED dimmer circuits are easily found with a quick internet search. They typically use a pot to control a high-gain PNP (NPN + PNP combo). Current-control arguably provides better flicker-free lighting even when dimmed (depending on PWM frequency).

An example current-control dimmer circuit can be found here on GitHub (GlowBall). It uses a manual pot, but that could be substituted with a digital pot (and probably parallel resistor to scale the resistance range appropriately depending on the digital pot resistance). Disclaimer: yes, that's my repo.

  • \$\begingroup\$ Thank you for your explanations! I will use a Logical MOSFET with the PWM pin of the ESP826. \$\endgroup\$
    – Kaymaz
    Sep 13 '17 at 7:42

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