Switches are a personal decision, but also a practical one. Sometimes you want a slick installation and maybe want to go switch-less and live with the disadvantages. Maybe everything must have a switch for that “just in case” time or maybe a hybrid and just a few key items have an emergency or convenience switch. This post walks through the options and trade-offs for each decision.
Switchless
This is our choice in BlackPaw, we built the van with the concept of a very clean cabinet look with no gauges, dials or switches. We had to compromise because we do not yet have an integration for the Autoterm heater, but that will come in 2026. So apart from that one panel, all our devices are controlled by one of the following method:
- Voice: Most of our devices can be controlled using a Home Assistant Voice Preview device. This allows us to use an “Alexa” style method to control the van, but a local and private one, unlike Alexa, Amazon are not listening in and we do not need to be connected to the internet.
- Tablet: We have a tablet in the cab for driving and a tablet in the living area when parked up. These tablets run Kiosk software that allows then to act as real Control Panels.
- Mobile Phone: Of course when out and about or even if it is more convenient we have dashboards specifically designed for the mobile phone screen size to allow us to control key items.
- Automation: Where possible we want the van to use automation and AI to predict what we really need so that we don’t have to do anything. If I always turn on a light when I enter the van and open the sliding door and it is dark, why would I want to do that manually every time. If I have to turn off a bunch of devices every time I start to drive, why do I want to keep doing that automatically. It makes sense to use AI and automation wherever possible.
A common question when going switch-less, is “What do you do if your automation fails?”. Well we mitigate it in a few ways:
- We only use quality relays, unlikely to fail
- If our Home Assistant server is down for some reason, we can use a webpage interface for each relay so that we can turn an item on/off from there
- We use plumbing ball valves that have a manual switch on them
Yes if an individual relay breaks or maybe the router breaks then we do have to break out the toolbox and replace the relay. For this reason we minimise the number of SKUs in the van and carry one of each item as a spare.
Switches
Switches may be required, either for convenience or emergency reasons. If it is just for convenience, then a wireless switch can be used. If it is for emergency, then a hardwired switch will be used to effectively bypass the relay channel and provide power to the device in case of relay failure.
Wireless Switches
There are some wireless momentary switches available, our preference are the Zigbee switches from Aqara which integrate well into the ecosystem we have rated devices for. The Aqara Wireless Mini Switch T1 uses Zigbee 3.0 and is ideal for almost anything, small with a single, double and long press programmability. It can be placed almost anywhere and uses a standard CR2032 battery. This switch is just communicating with Home Assistant, so it can be programmed to switch a Waveshare Relay channel or a Shelly 230V relay, ideal therefore for both DC and AC power control.
If you are not using voice control, not using your tablet or phone, this switch offers great convenience for a light switch when entering the Campervan. Wireless switches have no redundancy benefits, they are merely for convenience. All your automation infrastructure must be running for these to function.
Relay Hardwired Switches
One point to raise from the start for both DC and AC is the state capability of the switch. Some switches have an On and Off position clearly marked on the switch, maybe with some text or a mark or even an LED light. Home Assistant and the relays will not have a way to physically switch a switch and therefore the state of the switch can get out of synch with Home Assistant. If a physical switch is off and you turn on a device using Home Assistant, the physical switch will not change and therefore could appear to be wrong. For this reason push switches are useful for hardwired switches too. They have no state and therefore you are just toggling the device each time it is pressed. Please ensure you purchase a push button which is a lock switch, not a momentary switch. Lock switches are sometimes referred to as latching switches.
Our AC rated device is the Shelly 1 Gen 4. This relay has a hardwire switch capability rated for 13A. So any wired switch can be wired into the Shelly relay. Acmerota make well designed 230V hard wired push button switches.
Our DC rated device is the Waveshare ESP 8 channel Relay. This has 8 direct inputs which can be linked to trigger the 8 relays. Each relay channel can therefore have a hardwired switch. Each relay channel is rated at 10A, but if using a direct input channel to just turn on/off a relay channel, a 1A rated switch is more than enough. Unfortunately most DC push button switches do not look great because they are solid switches designed for industry or automotive purposes. However many switches rated at 230V will work with a 12V or 24V system.
Obviously it offers no redundancy should the relay fail itself, but still it gives some redundancy and convenience.
Power Hardwired Switches
This option is the ultimate redundancy option and involves powering the device in parallel to the relay, therefore the device can be manually powered using the switch.
A push button lock switch could be used for this scenario, but a single pole switch which shows its state maybe more useful. At a glance you can then see if you are bypassing the relay for control and just powering the device. Please remember under this scenario you are powering the device through the switch, you are not merely controlling a relay circuit. For that reason you will need a 10A switch for DC currents on the Waveshare relay and a 13A switch for AC currents on the Shelly 1 Gen4 relay. Please ensure you purchase a push button which is a lock switch, not a momentary switch.
You can use a single throw rocker switch to just power the device when turned on. If the automation systems are unavailable, then throwing this switch will just power the device directly.
Using a double pole rocker switch offers a slightly different solution. You could power the relay in one position and power the device directly on the other position. The off on the switch would offer a way to isolate the device and not power it either way. This option may be useful for some devices.
These options will allow you to power a device in the event of a complete Home Assistant, Network and Relay failure. Obviously power is still required for this option to work.