You could also use a crystal for the ATtiny and get the same accuracy as the RTC. It should be accurate to about 20-30 seconds per month with a good crystal.
The internal oscillator only has an accuracy of around 1% after you calibrate it. It would be off by over 7 hours after a month. It’s also quite sensitive to voltage and temperature changes.
You could try using the e-ink buddy from Adafruit. I bought one for driving a price tag e-ink as well but have not tested it yet unfortunately. On their site they say that e-ink connectors are pretty standardized.
We need a picture of the entire pcb. The ribbon cable (technically a flex pcb, not a ribbon cable) is totally custom and not something you can put a signal on. The little green pcb looks like the driver, so we would need pics of that and maybe figure out where you can input some kind of signal.
These kinds of displays can be really hard te re-use. Often their driver is just a simple blob (chip on board) which would be completely custom. This can be made cheaply to order with as few as 500 units. So mass produced readers often use completely custom stuff to get down to a really low price. Unfortunately this means it’s not possible te repurpose the screens later.
Spi is the norm for hobby displays because they are made to be driven easily. There is a driver chip that receives the spi signal and drives the display. With an actual product this often isn’t the case and the screen gets driven directly.
My comment will not help you of any way. But I find it interesting that the current regulation in France (maybe Europe?) is that any store that sells electronics (and home appliance) has to take old electronics (and home appliance) for free.
Actually everybody pays a small fee when buying electronics. The tax changes regarding the difficulty to recycle the appliance. For example, the tax for a freezer is 13€ since you have to purge the gas, where it’s 1€ for a vacuum cleaner.
Call up your local Target, Walmart, Best Buy, or whatever equivalent you have in your area. They got battery recycling centers. Ask them how they want them delivered and what, if anything, they want done to the battery prior.
Not all Walmarts do that. I’m the electronics guy at Walmart and we definitely don’t at my location. The only kind of recycling we do is ink cartridges and the stupid little bin up front for plastic bags
To understand the original traces on each side of a circuit board, you can put a powerful flashlivht on the back to see through.
I can’t say if the hole is too wide and makes a short circuit with another close track.
Do you use flux ?
Have you cleaned the track with water on a coton tip ? (To remove battery leak) What kind of soldering wire do you use ? Shitty soldering iron does not stick.
I had the same issue with a circuit. Gently sanding and using flux solved my issue. But it was an ugly soldering. I am not proud of it. You are not alone.
awesome, I was struggling to figure out where tracers went, I’ll try the light trick.
I did try using flux, I tried cleaning it with a toothbrush dipped in isopropyl alcohol, but I’ll try water and bud tomorrow.
I think I’m using decent solder, I bought it from my local electronics store. It has no discernible branding but does contain a mixture which includes flux. My soldering iron is a fairly expensive one and has treated me well, but I don’t think I take good care of the tip.
I’ll try a sand as well tomorrow. Thanks for all the advice and encouragement :D
It’s a 2.5” SAS drive. They’re usually used in servers and typically spin a lot faster than consumer SATA drives. You won’t be able to use it in your PC unless you buy an HBA card and some adapters.
I got a used 8 port card from ebay for about $20 a few years ago. I had to flash different firmware to it using a DOS boot disk to disable raid though. It’s an obsolete card, but it’s been working fine in my NAS.
Looks like that’s actually “SATA Express,” which has lanes for both PCI and SATA - if you look at the other side of the connector (which you should have already shared!) you’ll see even more contacts. You can get either a PCI or SATA adapter in order to use the drive.
Edit: Probably SAS as others said. It uses the exact same connector, which is why I made that guess.
The relay will cause a short voltage drop when switching. This could be a problem if your circuit can’t handle a short voltage drop.
Probably the Mean Well has adjustable output voltage. If you can trim the output voltage of the power supply to a higher voltage than your battery, then you can probably just run each power source through a diode and merge them after the diodes.
note that if you do have issues with the voltage fluctuating when the relay switches, you can often connect a ceramic capacitor across the coil contacts of ~1uF along with a small diode acting as a flyback connected in reverse polarity, and it’s enough to smooth out a good bit of that draw and/or switch-off flux pulse. Filtering saves lives
Thanks, I don’t think there are any external settings for the power supply, but it does provide a few more volts than I strictly need. Toggling a single relay hasn’t caused me any issues in the limited testing I’ve done. A momentary drop to as low as 5V should be perfectly fine, although, looking over the specs for my components, I see I’m getting dangerously close to the upper limits for the power supply’s current rating. I’ll have to look into connecting 2 supplies in parallel (or getting a larger supply) I suppose.
I haven’t worked with battery backups yet, so I was thinking it would be best to keep that element simple to minimize potential issues like a trickle charge draining the battery unexpectedly, or damaging the battery from overcharge. The minimum requirement is just to ensure the hardware (a motorized ball valve) returns to a closed position if power is lost. The battery needs to provide at least 9V to power the motor, so I could use a 9V (or a few smaller cells in series) to keep it below the 12V supply.
With your solution using a diode on each voltage source, would there be any risk of a trickle charge draining the battery unexpectedly if the battery? If so, in that configuration I’d need to do more research and figure out how to use a BMS, rather than an externally recharged or disposable cell.
With your solution using a diode on each voltage source, would there be any risk of a trickle charge draining the battery unexpectedly if the battery?
Current flows from high to low voltage, but the battery is at a lower voltage than the supply. Check the diode’s datasheet for the reverse current at the voltage that would be across it. It should be negligible
Sixfab uses the Telit ME910C1-WW chip on some of their USB models and the Quectel EC25-A for others. They are available as M2 form factor inserts, or you can buy just the chip.
Thanks for the input. I had already looked up the EC25 which is based on the same Qualcomm chip and a tad larger than the L6, but am unfamiliar with Sixfab and the telit chip you mentioned. I’ll look them up more. Cheers.
Edit: the Telit chip is 28x28mm and is LTE UE Cat-M1 with 1Mbps up/down from what I understand. Does not seem to offer LTE cat 4 speeds.
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