Product design help needed... rotary switch

[Lee Ash]

Hi... My name is Lee, I own a company called Lash Creative which makes Bespoke Vaping devices. (Ecig stuff!) I am designing a new product at the moment which uses a DNA40 chipset.... this basically allows you to vary the power to a heating element... amongst other things. I am not an expert on electronics, I work with wood and metal, primarily on a lathe. The chip has a connection on the board for power up and a connection for power down... you would attach simple small momentary actuators and have them side by side. I would like to replace these with a rotating control... something that rotates both ways, infinitely and dials in the amount of power.... My question... is there such a thing? As I said, electronics is not my speciality, so any suggestions would be appreciated. Here is the DNA 40 chipset... top of the page.
**broken link removed**

Thanks Lee

 

[KeepItSimpleStupid]

yea, sort of.

This https://www.sparkfun.com/products/9117 is a rotary quadrature encoder, but it does not give you the outputs you need. The rotary encoder generally consists of detents; two signals 180 degrees out of phase; a push button; and sometimes an illuminated shaft (RGB LEDS are possible).

This won't get you to the UP/DOWN signals you need. This chip https://elmelectronics.com/ebench.html#ELM402, the ELM 402 and possibly others might. It still may have issues and it still might require some "glue logic" to interface to the DNA 40. The ELM402 is a PIC ucontroller pre-programmed to do this function.

Possible issues are voltage (The ELM chip 2-5V), the amount of time the buttons have to be depressed on the DNA 40 (Has to be within the limits of the ELM). What logic is being used.

Is that "contact closure" to ground, to +Vdd or part of a matrix switch. What is Vdd? Typically, the processor "pulls" up a pin to the supply voltage and the switch grounds it. Something called "debouncing" is done to ensure one press.

Two more chips can convert the output of the ELM to Open drain if a contact closure to ground is used.

The voltage across the switch and the voltage across the switch when pressed will help.

The encoder, could possibly eat power because two LEDS would have to be powered all of the time UNLESS you could make capacitive sensing work. (A whole nother topic).

 

[4pyros]

Looks like you could use a volume control pot with a built in power switch.
You may need a flip flop for the power up and power down signals.
Some thing like this;
https://www.parts-express.com/500k-audio-taper-potentiometer-with-switch-1-4-shaft--023-600

 

[KeepItSimpleStupid]

I didn;t realize it also had a "Potentiometer" mode.

Potentiometer:
As an alternative to the digital interface, an analog potentiometer can be used to dial in the
power setting. If connected to the UP/POT pads, the DNA 30D will automatically detect analog mode
and use the potentiometer instead of the buttons. Resistances between 1k and 10k ohms are
recommended. To reverse the direction of turn for adjustment, reverse the Potentiometer – and
Potentiometer + connections. Any type of potentiometer can be made to work – shaft, shaftless, slide,
etc.

Volume controls have a LOG taper, not linear. Bet the potentiometer suggested should be linear.

 

[4pyros]

Bet the potentiometer suggested should be linear.

You may be right but a LOG taper may work well enough.