Preamble
I’ve found myself in need of some baby monitors. In the past I’ve used a pair of prehistoric hand-me-downs, but I decided to go fancy this time.
Getting started
The criteria were that it was to have no knowledge of wifi or cloud connectivity, and I wanted it to have reasonable range. Range more reasonable than Bluetooth - I might as well just sleep next to them then.
I did look into throwing together a DIY solution based on an RPi and cameras and whatnot, but eventually decided that even after sourcing the day- and night-vision components and wiring them together, I’d still have to do software and manufacture a decent-looking enclosure. This list was in order of difficulty from easiest to hardest. I’ve discovered I can imagine wonderful 3D designs in my head, but severely lack the skill to make em into a proper model.
Another issue was that after some initial research on ready-made products, I was under the impression that I needed FHSS, which is claimed to be hack-proof (heh). I imagine it to actually be more difficult to spy on that regular-ass wifi.
And I’m not fond of people other than myself and The Wife looking at my baby.
So I settled on a HelloBaby something or other. It promised the aforementioned FHSS and claimed to have over 10 hours of battery life. Perfect! Not that I plan to let the baby sleep for 10 hours, but neat nonetheless!
Discovery
I ordered that HelloBaby something or other from Jeff (Bezos) and accidentally timed it to be a christmas present for the family.
After all the initial buzz and a generous helping of Good Husband Points (since it was a surprise) I started unpacking it to see what we were working with and made an annoying discovery.
The claimed 10-hour battery life applied to the parent unit. The cameras didn’t have batteries and only worked when plugged in.
I don’t have outlets on the balcony… And even if I did, it’d still be annoying.
Wat do?
Well the first idea was to send the set back and find a new one. Unfortunately I could not find any sets that included a battery for the cameras.
Next idea was to look at giving them custom batteries. The wall adapter said it output 5 volts and my watt-o-meter said the camera consumed 1.6 watts of power while transmitting. I also happen to know that USB carries 5V and is well capable of carrying 1A. Quick mathing returned that a 10k mAh powerbank should last for roughly 231 years and only cost like 25 euros. Neat!
The cables use a barrel-jack and first instinct was to browse electronics stores for such jacks so that I could snip the end off some Micro-B cables and be done with it. Well I’m not good at guesstimating the barrel-jack sizes, and the bloke at the physical store wasn’t, either.
Next idea - why am I even considering barrel-jacks? Everything is supposed to be USB-C nowadays, right? That same electronics store even had some pieces that did the regular 4-wire usb cable with a Type-C port. Might as well.
The teardown
Here’s what my HelloBaby something or other looks like on the inside.
My plan is to drill a new hole for the Type-C port and bring GND and V+ to the PCB.
The next like a week or so I spent digging through the two electronics components stores in Estland. A week?? Yea, the baby, remember? For those unfamiliar with the concept, descendants consume time. Lots of it.
The assembly
I finally found a set of USB Type C sockets that expose the regular 4 VCC, D+, D-, and GND wires, which I could
work with. I put my laptop charger in the socket (or rather, the socket on the charger) and expected multimeter to show
activity.
Well it didn’t.
I blame the laptop charger’s USB-PD-ness. PD is supposed to be a standard over which the device and the charger agree on a voltage to charge with and I suspected the reason the charger was not giving charge because it didn’t have anyone to talk to.
But it is also supposed to default to 5V when PD is not used…
Sudden thought
I could continue investigating why my new USB-C ports are not displaying 5V on the multimeter due to probably not talking with me USB-PD charger.
Or I could stop being an idiot and perform a vendor-neutral-internet-search to discover that the plug is most likely a DC 3.5x1.35 mm jack and I could get a ready-made cable for 4€ from the same electronics store.
In general
One final annoyance still remained, though. The absolute cheapest powerbank I could get my hands on is rated to operate between +5 and +35 degrees european, which is well above the -5 to -15 degrees that were outside during Christmas time. However, it is now spring and the temperatures are up between an acceptable range.
Also, by the power of 3D printing made a thing to hold the camera at an angle to better show the descendant sleeping in the BogaBoo Donkey stroller.
