Clean looking sensor node
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@Nca78 said:
Hello,
one of my big concerns with sensors is to have something good looking without my wife asking me what this ugly plastic box is. After failed searches for good looking and small enclosures, I decided to search for electronic items and only keep their boxes. I have tried with a tiny 333cm 2$ mp3 player and managed to fit a jmodule and sensors + cr2032 inside. But the plastic is still looking too cheap.
Then I discovered those great looking wireless chargers and bought 2 different models, they are pretty bad at charging but they look really good. Only problem: they are flat. No way to put a jmodule inside so I went for an EasyPCB and removed the plastic stripes on the headers to make the pcb as flat as possible. I choosed the smaller (but thicker) black one as in the other the PCB + NRF24 was already too thick (because of the crystal).
https://www.aliexpress.com/item/QI-Wireless-Charger-Charging-Pad-for-Samsung-Galaxy-S7-S6-edge-Note-5-Nokia-HTC-8X/32694769031.html
https://www.aliexpress.com/item/Factory-price-Qi-Wireless-Charger-Charging-Pad-for-LG-V10-Other-Qi-Phone-Mmar25/32639543557.htmlTo fit the pcb I had to remove the right part, and then cut the corners. Still, the antenna of the NRF 24 was too much so I had to cut it too :D I put a 10cm wire instead, soldered at the beginning of the cut pcb antenna and ... it works really well !
Unfortunately I couldn't fit a CR2032 after putting the PCB, so I decided to experiment with alkaline button cells, the more convenient solution was to take tiny ones (LR41/AG3) and put them between power connectors of the PCB.
I also added a bicolor led (green / red) aligned with the led window of the charger, it blinks at each sending loop, wether data is sent or not so I know it's still running. When battery level is high it blinks green, when it gets low it will blink red color so I know it's time to check if I have spare batteries. Also, voltage drop is smaller on red led so it's brighter, green led is dim even at full battery and would be invisible with low battery.I use a SHT21 sensor and at the moment I send every minute (if values changed) the temperature, humidity, battery level (%) and battery voltage (to have history). With the led blinking that's a lot to bear for LR41 batteries (rated between 25-30 mAh) but it's done on purpose, to see how fast they get empty.
The PCB ended up pretty atrocious as I did many trials and errors with it (and kept long pins 11,12,13,RST to program the board and have to bend them to fit inside the box) but fortunately when I close the box everything is hidden and the sensor really looks good. With the led flashing it really feels like a commercial sensor you could buy in a shop. I put the sensor not too far from the usb plug hole, but there are also a opening all around the bottom of the enclosure, so I have no visible difference in measure temperature/humidity when I open or close the box.
Next step is a dedicated PCB to have a clean board and be able to fit bigger coin cell(s).Wow I'm typing too much :D Here are the pictures...
Looks a bit like a solar garden light, whch is also round and which you can buy for $1 and includes a small solar panel, LED, and rechargeable battery. Someday I'm going to investigate whether I can get a wireless node to run off energy it stores from mere ambient light and never need battery maintenance. Seems like it should be possible.
I agree that finding cases with decent industrial design is a problem. Typical project boxes don't really cut the mustrd. One advantage of a small node is that it can fit into more things and hopefully remain inconspicuous. On the other hand, if you want to measure temp-RH, you need to have decent airflow. I guess yours accomplishes that by having no bottom? Maybe it should be white so it doesn't heat up just from surrounding light.
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So, here's an example of such a $1 solar garden light:
Don't buy them for outdoor use, although that's what they're sold for. They'll rapidly corrode in wet weather and then cease to function. However, that shouldn't be a problem indoors.
Demounting the solar puck, it looks like this:
Here's the flip side with the guts removed:
Inside I put one of my RFM69HW temp-RH nodes. As you can hopefully see, there is room to spare.
These close-up photos probably make the puck look larger than it is. It is just 2-1/4" in diameter and 1-1/8" tall.
What do you think? Would it have good WAF? This one is a bit crufty because it was outside for about a year, and then I plucked it for these photos. When brand new they look more clean and polished, and so perhaps if kept indoors they would stay that way.
One possible concern with this particular example is that it has a metal band around it. That's not so ideal for an RF node, but it may not matter, as I tested the PCB node (just by itself, without the solar puck) within a closed refrigerator and still got adequate signal from it.
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I have bought one of those too and there's a post about recycling them as soil humidity sensors here on the forum.
There is now ways these can compare in term of WAF ;) Garden light is way more bulky (at least twice the height and just a few mm less in diameter), the solar panel makes it look ugly, there's no air flow when you put it on a table, no clear slot to show the led light, you will need to have the antenna outside because of the metal enclosure (it's the case in mine at the moment also, but it will be fixed with dedicated PCB. Sensors run ok in my refrigerator too, but I suppose it's because there's no metal in the door and an opening big enough to let the signal go out)... And they cost over 3$ in the only shop where I have seen it here, don't know why as China is a neighbour...
The box I use has a bottom, you don't see the circuits and the box is tightly close, it looks really like one you would buy in a shop.
As the charger must generate some heat, there are opening all around the bottom, providing a good airflow.
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I have to agree that sitting side by side, yours does look nicer. Nice find!
At least with my wife anything which has a protruding wire gets low WAF. I have to agree with her on that. You can curl the wire and fit it inside the case. You'll lose some signal strength, but that's why I opted for the RFM69HW, which has plenty of link budget. Etching an antenna starts to get complicated if you want it to work well.
Last night I found a square version of the solar puck that was all plastic (i.e. no metal band around it). However, if you don't like the look of a solar cell on top, it would be a non-starter for you.
In general, though, I think your idea of re-using the case of some well crafted looking product is the way to go. I suppose 3D printing something might work, but I'm not equipped for that, and let's face it: it takes both time and talent to make something from scratch which also looks nice. Even companies like Apple I'm sure go through a lot of iterations, and those are full-time professionals who specialize in that.
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From what I have seen 3D printing cannot produce such a polished look, at least not with the entry level machines. So you need polishing and/or coating to have something good looking. It's good for POC but for a good product you need plastic molding and for that to be reasonnable in price you need.
For the antenna it will be fixed with the dedicated PCB, the PCB antenna of the NRF24 will fit inside the box.
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From what I have seen 3D printing cannot produce such a polished look, at least not with the entry level machines. So you need polishing and/or coating to have something good looking. It's good for POC but for a good product you need plastic molding and for that to be reasonnable in price you need.
For the antenna it will be fixed with the dedicated PCB, the PCB antenna of the NRF24 will fit inside the box.
@Nca78 said:
such a polished look
Actually it can have that look if you print with ABS and treat it with acetone vapor afterwards.
For example look at these picturesHave treated my prints that way many times and the result is very good.
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If anyone else has suggestions on good looking cases to use, please do post them to this thread. This will be an easier search if we pool our knowledge.
Meanwhile, I think I'll order one of the same charging pads as the OP so as to try it out. It's actually cheaper than many of the much worse looking project boxes, so thanks for posting the links.
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Hello,
one of my big concerns with sensors is to have something good looking without my wife asking me what this ugly plastic box is. After failed searches for good looking and small enclosures, I decided to search for electronic items and only keep their boxes. I have tried with a tiny 333cm 2$ mp3 player and managed to fit a jmodule and sensors + cr2032 inside. But the plastic is still looking too cheap.
Then I discovered those great looking wireless chargers and bought 2 different models, they are pretty bad at charging but they look really good. Only problem: they are flat. No way to put a jmodule inside so I went for an EasyPCB and removed the plastic stripes on the headers to make the pcb as flat as possible. I choosed the smaller (but thicker) black one as in the other the PCB + NRF24 was already too thick (because of the crystal).
https://www.aliexpress.com/item/QI-Wireless-Charger-Charging-Pad-for-Samsung-Galaxy-S7-S6-edge-Note-5-Nokia-HTC-8X/32694769031.html
https://www.aliexpress.com/item/Factory-price-Qi-Wireless-Charger-Charging-Pad-for-LG-V10-Other-Qi-Phone-Mmar25/32639543557.htmlTo fit the pcb I had to remove the right part, and then cut the corners. Still, the antenna of the NRF 24 was too much so I had to cut it too :D I put a 10cm wire instead, soldered at the beginning of the cut pcb antenna and ... it works really well !
Unfortunately I couldn't fit a CR2032 after putting the PCB, so I decided to experiment with alkaline button cells, the more convenient solution was to take tiny ones (LR41/AG3) and put them between power connectors of the PCB.
I also added a bicolor led (green / red) aligned with the led window of the charger, it blinks at each sending loop, wether data is sent or not so I know it's still running. When battery level is high it blinks green, when it gets low it will blink red color so I know it's time to check if I have spare batteries. Also, voltage drop is smaller on red led so it's brighter, green led is dim even at full battery and would be invisible with low battery.I use a SHT21 sensor and at the moment I send every minute (if values changed) the temperature, humidity, battery level (%) and battery voltage (to have history). With the led blinking that's a lot to bear for LR41 batteries (rated between 25-30 mAh) but it's done on purpose, to see how fast they get empty.
The PCB ended up pretty atrocious as I did many trials and errors with it (and kept long pins 11,12,13,RST to program the board and have to bend them to fit inside the box) but fortunately when I close the box everything is hidden and the sensor really looks good. With the led flashing it really feels like a commercial sensor you could buy in a shop. I put the sensor not too far from the usb plug hole, but there are also a opening all around the bottom of the enclosure, so I have no visible difference in measure temperature/humidity when I open or close the box.
Next step is a dedicated PCB to have a clean board and be able to fit bigger coin cell(s).Wow I'm typing too much :D Here are the pictures...
@Nca78
I just ordered both charger pads that you had linked to. They should arrive in about a month, and then I'll give them a try.You can save on both size and thickness by using a surface mount NRF24L01. Gert Sanders already has a node like that he has posted.
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Hello,
one of my big concerns with sensors is to have something good looking without my wife asking me what this ugly plastic box is. After failed searches for good looking and small enclosures, I decided to search for electronic items and only keep their boxes. I have tried with a tiny 333cm 2$ mp3 player and managed to fit a jmodule and sensors + cr2032 inside. But the plastic is still looking too cheap.
Then I discovered those great looking wireless chargers and bought 2 different models, they are pretty bad at charging but they look really good. Only problem: they are flat. No way to put a jmodule inside so I went for an EasyPCB and removed the plastic stripes on the headers to make the pcb as flat as possible. I choosed the smaller (but thicker) black one as in the other the PCB + NRF24 was already too thick (because of the crystal).
https://www.aliexpress.com/item/QI-Wireless-Charger-Charging-Pad-for-Samsung-Galaxy-S7-S6-edge-Note-5-Nokia-HTC-8X/32694769031.html
https://www.aliexpress.com/item/Factory-price-Qi-Wireless-Charger-Charging-Pad-for-LG-V10-Other-Qi-Phone-Mmar25/32639543557.htmlTo fit the pcb I had to remove the right part, and then cut the corners. Still, the antenna of the NRF 24 was too much so I had to cut it too :D I put a 10cm wire instead, soldered at the beginning of the cut pcb antenna and ... it works really well !
Unfortunately I couldn't fit a CR2032 after putting the PCB, so I decided to experiment with alkaline button cells, the more convenient solution was to take tiny ones (LR41/AG3) and put them between power connectors of the PCB.
I also added a bicolor led (green / red) aligned with the led window of the charger, it blinks at each sending loop, wether data is sent or not so I know it's still running. When battery level is high it blinks green, when it gets low it will blink red color so I know it's time to check if I have spare batteries. Also, voltage drop is smaller on red led so it's brighter, green led is dim even at full battery and would be invisible with low battery.I use a SHT21 sensor and at the moment I send every minute (if values changed) the temperature, humidity, battery level (%) and battery voltage (to have history). With the led blinking that's a lot to bear for LR41 batteries (rated between 25-30 mAh) but it's done on purpose, to see how fast they get empty.
The PCB ended up pretty atrocious as I did many trials and errors with it (and kept long pins 11,12,13,RST to program the board and have to bend them to fit inside the box) but fortunately when I close the box everything is hidden and the sensor really looks good. With the led flashing it really feels like a commercial sensor you could buy in a shop. I put the sensor not too far from the usb plug hole, but there are also a opening all around the bottom of the enclosure, so I have no visible difference in measure temperature/humidity when I open or close the box.
Next step is a dedicated PCB to have a clean board and be able to fit bigger coin cell(s).Wow I'm typing too much :D Here are the pictures...
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@Nca78 said:
. No way to put a jmodule inside so I went for an EasyPCB ...
By the way, what is an "EasyPCB"?
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@NeverDie said:
By the way, what is an "EasyPCB"?
https://www.openhardware.io/view/4/EasyNewbie-PCB-for-MySensors
@mfalkvidd
Thanks for the link. I had thought it might be a new easy way to create PCB's at home from scratch, but it's totally different from that. It looks good for its own merits though. -
Inspired by the OP's original post, I notice that if I do a search on "power bank case" (e.g. https://www.aliexpress.com/af/power%252Bbank%252Bcase/6.html?site=glo&g=y&SortType=price_asc&SearchText=power+bank+case&isAffiliate=y&initiative_id=SB_20161013135103&needQuery=n&isFreeShip=y), it turns up a lot of possible low cost cases (which may or not be to your taste, but as you go up in price, the fit and finish also improves). Example links for a couple inexpensive ones are:
Of interest to me are ones like the second link that are already designed to hold two cells, because I envision that is what I would probably use for most nodes that run on battery. For a node that's meant to run from a usb charger, the first one (or similar) might be fine and could probably be adapted for that purpose.
Last December I got a very nice power bank, which was on-sale at Amazon for just $6.50, including Prime Shipping:
https://www.amazon.com/gp/product/B00NUS0BQW/ref=od_aui_detailpages00?ie=UTF8&psc=1
It even came with rechargeable lithium batteries already installed, and for what it does it works quite well. If I could find just a case like that but priced even lower, I'd probably get it.Here's one that's not as attractive, but it is lower priced, and it clearly has space for both batteries and for a wireless sensor module:
https://www.aliexpress.com/item/Consumer-Electronics-Shop-Free-shipping-For-iPhone-LED-5x-18650-Dual-USB-Power-Bank-Battery-Charger/32600920016.html?spm=2114.30010308.3.179.KlmmHY&ws_ab_test=searchweb0_0,searchweb201602_5_10065_10068_10067_10069_10017_10080_10082_10081_10060_10061_10062_10056_10055_10054_10059_10078_10079_10073_10070_421_420_10052_10053_10050_10051,searchweb201603_4&btsid=532dcd62-0435-446f-a697-950ed308b3ab -
@NeverDie yes you are right the SMD version of NRF24 is the way to go, there is not way to fit both a regular sized NRF24 and a non SMD atmega. SMD NRF24 is not too hard to solder so it's the better compromise. I can fit it with pro mini and CR2032 on the available space for the black charger.
For the other one outside thickness is 8.7mm only, and to that you have to remove the thickness of the plastic shell and also recessed rings for the "soft" rings on top and bottom. In the end the thickness available inside on all the surface is below 6mm. My SMD plastic holders for CR2032 are 5mm, with 0.6mm for a thin PCB that doesn't leave much for the solder at the bottom of the board, they have to be centered inside the ring of the bottom plate to fit. It will need some drilling in the bottom plate to allow some air flow. But it's looking good, better than the black one and a bit cheaper so it's probably worth a bit of optimization :)For powerbanks I have tried a few also, but as they are made for 18650 they are quite bulky. The cheap one as on your second link (and the one with square section too) have a good finish, I thought about using them as door/window sensors but the big "Power" text engraving and the holes for USB put me off :P
I'm thinking about using an aluminium xiaomi powerbank enclosure to use as a slick gateway though, with PA/LNA NRF24 and antenna outside. -
Found a few more things. If something a tad bigger than the OP's puck were needed, then there's this at almost the same price:
http://www.ebay.com/itm/Q8-QI-Wireless-Charging-Pad-2-USB-Port-Splitter-HUB-Charger-Pad-For-Phone-F5/301913729117?_trksid=p2047675.c100623.m-1&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D39345%26meid%3Decb1959e8f164eb5ad0a17aeaa297f59%26pid%3D100623%26rk%3D3%26rkt%3D6%26sd%3D252485416371Also, as far as solar cells go, I agree that some of them can be ugly looking. Not all of them though. Here's a couple that seem like they wouldn't look too bad, but for most things solar the prices are much higher than for a non-solar version (as you'd expect);
http://www.ebay.com/itm/12000mAh-Portable-Waterproof-Solar-Charger-Dual-USB-External-Battery-Power-Bank-/112160398867?var=&hash=item1a1d47de13:m:mSNAshLEYCjRnRKBS7jvE7Ahttp://www.ebay.com/itm/272407702880?var=571371942032
I like the look of the last one better, but of course it costs more than the other solar cell charger, so that's the trade-off.
From what I've read, most of these portable solar chargers would take a very long time to convert enough solar into enough stored energy to charge a phone, and so people end up mostly charging them from a usb charger, defeating the main purpose purpose of it. However, for powering a wireless sensor node, I suspect they capture enough solar from ambient light that they could be retrofitted for that purpose., at least for nodes that can sleep and don't always need to be running.
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Ah yes the "Q8" square charger looks great, I'm waiting for my new credit card to arrive to be able to order one :D It's a bit bigger but it looks slick and it would allow to combine a few sensors inside. It could also contain a charging circuit and lipo to have rechargeable sensor.
For the others, well I believe I would get high WRF (with R like rejection) instead of WAF :D
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Ah yes the "Q8" square charger looks great, I'm waiting for my new credit card to arrive to be able to order one :D It's a bit bigger but it looks slick and it would allow to combine a few sensors inside. It could also contain a charging circuit and lipo to have rechargeable sensor.
For the others, well I believe I would get high WRF (with R like rejection) instead of WAF :D
@Nca78
I'm not really offended by the QB logo, but I'm guessing you would prefer one without the QB logo:or
Mainly because of the lengthy shipping delay, I think I'll get one of each and then decide which I prefer. Things don't always look the same on a website as they do in real life.
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Looking at the containers in our pantry here, I notice a lot of them have lids that, though they lack "bottoms", in many respects look a lot like the generic "puck" shape of the OP. For something that sits on a table top, you'd never know it doesn't have a bottom. These would be entirely free, because as my family here uses up a container, we invariably just throw it out. :-)
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Looking at the containers in our pantry here, I notice a lot of them have lids that, though they lack "bottoms", in many respects look a lot like the generic "puck" shape of the OP. For something that sits on a table top, you'd never know it doesn't have a bottom. These would be entirely free, because as my family here uses up a container, we invariably just throw it out. :-)
@Nca78 said:
I just today received an all white version of this (purchased it from ebay), but I wouldn't recommend it (well, at least not this color). The case itself is all white, which is what I wanted, but the silicon ring embedded in it is more of a cream color, and so it ruins the look by making it look old and/or dirty. It doesn't look like the photo on the web page. Also, as perhaps the OP pointed out, there are no vent holes, though they could be drilled.
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Here's another one, but this one I like. For a sense of scale, I photographed it with my large TH sensor sitting on top:
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You're receiving thing pretty quickly (as you received the PCB in less than 2 weeks, too), you're lucky !
I have no problem with the white ring on mine, it's not the same color than the plastic but it's not looking bad to me. Maybe different model, maybe a question of taste ;)
