I’d like to measure the levels of harmful gasses in my living room, I can do this with a VOC sensor (volatile organic compound; will pick up CO2, cigarette smoke, burning candles, etc.).

So, I’m going to wire up an ESP32 with a solid state gas detector, and a VOC sensor!

This one here, a ZP07-v4.0 outputs levels low, mid, high of VOCs in the air around it. This will not tell me what the VOCs are though.

This little beauty will though, and give me “measurable” levels of CO, nitrogen dioxide and ammonia. Sweet.

Now, to wire this all together to an ESP32!

Some coding…

Voila, an air quality sensor for my living room, that reports back to my home automation server every 5s. I’ll start graphing the levels soon, see if I can glean any useful info, how many cigarettes smoked, how “stinky” apartment is ?

Woop! I survived the shitshow that was 2020. Now, what to do?

I know, I’ll extend my home IoT network, add more sensors, relays, LEDs, some well-being monitoring schtuff. Planning to control/monitor with HomeAssistant running on an RPi 4 (MQTT server, and ESPHome server).

For the rest of January I’ll be adding an ESP a day!

First, a simple 12V relay, powered by this cute lil ESP-01s. Relay will power 2 computer case fans, 1 which will pull air through a carbon filter; 1 will cool an RPi cluster.

What? Why?

Found acrylic panel in DIY store, was given a vacuum cleaner free if I did “something cool with it”. I kinda wanted access to a vacuum former, but fuck it, might as well build.

Planning

Found 50*50cm 5mm thick sheets for 20 monies, got two. 2m outer edge, bought 2m of nice thick wood, cubic wood too. Found this amazing drill attachment for making big holes of different sizes, bought it.

Sketching

It’s a box, I didn’t bother.

Getting into it!

• 2 x 50cm * 50cm Acrylic sheets 5mm thick
• A drill with 3mm drilly bit
• TIME
• Wood (for frame)
• Silicone sealant
• Tensioning rods
• Heating element
• Hinges
• Clips
• An assortment of screws
• Permanent markers, fine tipped, 2 colours minimum

First things first. Sheets are 50*50cm, I need to.make a frame of outer size 50*50, and inside, a frame of smaller 6mm square wood to provide additional support. In one of the sides, there needs to be a hole for the vacuum cleaner inlet.

With the frame made, and additional supports installed for the acrylic base, cut to the inner dimensions of the frame; I think this will make for a better way to maintain a seal, and thus partial vacuum.

Now to paint! I don’t want to be regarding wood all the time. I use an acrylic plasticote paint, yellow, on inside and out. Hmmm. I should have sanded this frame inside and out first :/ oh well

Now, to put in the base acrylic layer, this will be screwed to the support, and silicon sealant used above and below!

Screwed in, and sealed, the bottom looks like this:

Sealing gaps on the outside was done, and I moved to the top side.

Before laying the top plate, a zigzaged a metric shittonne of sealant, aligned, lowered the acrylic plate, and pushed hard on edges, and started screwing with 6-8mm legnth screws, 5 each side (because science, lol, na I didn’t have enough screws for more ?). Thanks to my trusy Bosch IXO for making the screwing easy (also, omg, it charges over usb!).

Now, all that is left is to test. I have a spare vacuum cleaner ~1800 watts and a hole in the side of this box that almost fits the business-end tube in, would perfectly fit a plumbung tube, I would do a screw adaptor… (I’ll probably slightly enlarged hole by excessive sanding).

NOTE: Testing comes in next post, I do wonder if I need to drill some more teenie tiny 1 mm holes to the top.

NOTE 2: heatingy bit comes in next buildlog!