ESP8266 Community Forum

- Wed Jul 21, 2021 5:07 pm #91925 Has anybody found a keyfob (or similar) with an embedded ESP8266, ideally with enough access to pins to re-flash it? Or tried putting an ESP8266-01 in a keyfob shell?

I'm currently using standard RF keyfobs talking to a receiver with serial out (to an ESP826, ESP32 or whatever), but it would be great to put some local intelligence in the keyfob itself.

Any suggestions welcome - of a commercial device to hack or of a viable "empty shell".

Cheers
Sean

- Thu Jul 22, 2021 4:41 am #91928 Key fob: no, USB thumb drive form factor: yes.

The main issue is that putting an ESP8266 into a (RF tag) key fob is just not feasible: an ESP needs a lot of power (3.3V@350 - 500mA) and there's not really a battery small enough to both fit in a fob and able to supply the necessary juice
And powering it off the millivolts from the coil that a RF tag transmitter generates, is also not really an option (or you must turn it into a QI charger, but then the whole idea behind an RF tag is just gone).

Assumption is the mother of all f*ckups. At least: that's what I'm assuming.

- Sun Jul 25, 2021 4:31 am #91951 Thanks Quickfix. Point taken about power consumption.

I'm thinking of leaving the device either off or in deep sleep mode, only waking up on a keypress. There will be a delay between the first keypress and a command being sent, but I can live with that. It could even do something like flash an LED until wifi is up.

I'm going to try getting an ESP-01 into a casing like this... https://uk.rs-online.com/web/p/remote-control-fobs/4510668

Years ago I experimented with deep sleep, waking with RST and/or EN, etc. butt not in great depth. If anybody can suggest an optimal arrangement for low power consumption asleep with reasonably fast wake-up, I would love to hear about it!

Cheers

- Sun Jul 25, 2021 1:48 pm #91952

If anybody can suggest an optimal arrangement for low power consumption asleep with reasonably fast wake-up, I would love to hear about it!

Have a look at this:- Aggressively Low Power with the ESP8266

Be nice if you report back if you have some success.