A friend of mine was looking for inexpensive power outlets/strips with USB control and he couldn't find a decent one. It came to my mind that this is a great project for Hexabitz! There are plenty of wifi-controlled outlets out there but what if you want a CAN-controlled power socket? Or IR-controlled? or simply old-fashioned serial port? It's almost impossible to find something off-the-shelf to cover all these needs so why not build your own? Hexabitz modules are so tiny and you can combine together whatever modules you want to get any weird functionality! Turned out a really fun project trying to squeeze modules in such a tight space.
WARNING: Voltages higher than 24V can be dangerous! Make sure you know what you're doing and use protection (circuit breakers, etc.) whenever possible. Don't attempt this without supervision if you haven't dealt with higher voltages before.
Files
Firmware 1.zip
Gesture-controlled power strip. H08R60 (IR module) custom firmware.
I got few power strips from Home Depot. It's really difficult to tell if there's enough room inside before you open them up so you might need to experiment with few models (but at least make sure they're wider than a single module, i.e. 30mm, which almost all power strips are.) In some power strips, there's enough space to stuff in modules without any modifications. In other ones, you might need to remove the power switch or one or more outlets. In most cases, you will probably need to at least remove some internal ribs or drill some holes. Also, wiring gets tight with thick power cables so try to get the spaciest power strip you can find!
2
Choose what modules you want in there
I modified two power strips. Once has the IR ToF sensor module (H08R60) to replace its power switch so that you can use hand gestures to turn on/off and the other one has a BLE and a USB modules so that you can control it via a smartphone or connect to your PC and use the CLI. Of course you need an AC relay and a 3.3V power supply as well as few mounting modules. Here's the complete list.
Setup 1
1 x 600 VAC / 1.2A Solid State Relay Module (H0FR60)
1 x 3.3V / 1A DC-DC Buck Power Supply Module (H03R00)
4 x M2/M2.5 Triangle Mounting Hole Module (T00R10)
1 x power strip
M2 nylon screws and spacers (height according to your design)
Ended up using Mini USB-B module instead of the USB-B in the picture to reduce size.
3
Start assembling the modules together and find out best fit
This step will require some iterations. You will need to find the best place inside the power strip and maybe remove some internal features that are blocking the modules. Remember that you can also go vertical and tune the vertical spacing based on module height, available space the way you want to access your modules, etc.
Not applicable. The warning needs to be on the product page for your relay module, and front and center on any example projects (like this one) that use line voltage.
This is a hobby project using a hobby and prototyping hardware. We always assume users have full responsibility of their actions and they know what they're doing. I don't think this is different from someone soldering or welding something or using the mill or the electric saw for a project. The relay module is rated up to 600 VAC max by its components and there's a warning label of high voltage but it's not a certified product since it's not intended for commercial use.
Not good enough in my opinion. Exposed 120vac is quite a bit more dangerous than soldering. You should spell out in clear terms that anyone using this product to control line voltage needs to know what they're doing, and make the warning the first thing the user reads. Example from Sparkfun: https://www.sparkfun.com/products/15032 and Adafruit: https://www.adafruit.com/product/3191
I like the colored warning labels in Sparkfun website. Hopefully we can make something similar in the future. Right now I'll add a textual warning to the page and that should do it. I'm in direct contact with all initial users who have access to our modules and I'm making sure already they know what they're doing (not targeting beginners yet). Thanks for the advice though!
Sharing a project like this in an official capacity seems like it opens your company up to all sorts of legal liability. I'm not a lawyer, but telling your customers to hack on 120vac stuff might be a bad idea. At the very least, you need a big warning in the project description about line voltage safety. What kinds of line voltage related certs (i.e. UL) do your 120vac relay modules have?
I actually just remembered that we have a legal disclaimer at the end of this article regarding our hardware and software: https://hackaday.io/project/76446-hexabitz-modular-electronics-for-real/log/117213-hexabitz-software-architecture although I know most people don't read these things.