user interface, (U.S.) decora style device sized - Page 1
Forum section: electronics / projects

author: ratio
author_rank: Regular Contributor
timestamp: September 11, 2017, 09:23:33 pm
content: Before I get diverted onto yet another side project, does anyone know of a ready-made (or kit) user interface that will fit in a standard U.S. electrical back box, preferably with a decora-style face? (This will be in a separate box, no mains power in the box to worry about.) Ideally, it'll have a small matrix screen, a clickable rotary encoder, 5V powered, & communicate via I2C, but nearly anything that fits, with a line or two of characters & three or four buttons will work.

author: rstofer
author_rank: Super Contributor
timestamp: September 12, 2017, 02:38:38 pm
content: Maybe one of the small OLED displays?https://www.sparkfun.com/products/13003

author: ratio
author_rank: Regular Contributor
timestamp: September 12, 2017, 04:50:02 pm
content: Yah, that's about the display I'm thinking of, but I was hoping to find something all ready to go, just mount a small PCB on the back, land the I2C, and done. I've got a sneaking suspicion that the device yoke will have to be custom made, either 3D printed or ordered from somewhere; and I don't have a 3D printer.http://www.leviton.com/en/docs/ig-gfci_500px.pngshows the approximate dimensions I want to fit.

author: rstofer
author_rank: Super Contributor
timestamp: September 12, 2017, 06:25:09 pm
content: Why not treat your device like a thermostat which doesn't even require a box?If you really want the box, your gadget could be secured to the box but not fit inside the box.One problem with small displays is demographics. Who is your customer base? Hopefully, it will be people with money and they will tend to be older and have eyesight problems. Bigger is better.Here is an example of a thermostat where the designers got it right. The fonts are large, the display is bright and even old people can operate it:https://www.amazon.com/dp/B00SYPSIRU/ref=asc_df_B00SYPSIRU5166614/

author: ratio
author_rank: Regular Contributor
timestamp: September 12, 2017, 10:42:39 pm
content: Funny you should mention thermostats--I do that professionally. Fitting into a box isn't critical, but there's one there already. If I went with something else it'd need to cover that. This is a one-off I expect. I came across an industrial three phase fan the same time I was looking for a whole house fan, so I popped it in & picked up a cheap Chinese VFD to run it from single phase. It works great, but I'm limited on control options unless I want to shell out for industrial controls. What I want is a user-determined 4-20mA current loop signal that will turn off after another user settable 1-12H delay. I've been using a wind-up timer, but if I want to slow the fan down I have to go to the VFD keypad. I had an analog-output stat for a while, but that alone isn't enough control. A week or so ago I came across a current-loop transmitter (http://www.ti.com/lit/ds/symlink/xtr117.pdf), and that got me thinking again. The OLED screens need more current that I'd have available with current loop control, but a 2-10V signal would be fine too, or maybe there's something else that would be fine with <4mA available at switched-on-zero-output.