{"id":8807,"date":"2026-04-07T13:27:39","date_gmt":"2026-04-07T11:27:39","guid":{"rendered":"https:\/\/willem.aandewiel.nl\/?p=8807"},"modified":"2026-04-08T11:07:24","modified_gmt":"2026-04-08T09:07:24","slug":"soft-power-latch-2","status":"publish","type":"post","link":"https:\/\/willem.aandewiel.nl\/index.php\/2026\/04\/07\/soft-power-latch-2\/","title":{"rendered":"Soft Power Latch"},"content":{"rendered":"\n

76 keer bekeken \/ views <\/p>\n\n\n\n

In my post about the handheldAerosolSensor<\/a> I use a circuit to switch power to the system with a single push-button, and then let the ESP32 turn it off again after completing measurements. This is an extremely efficient method because the alternative\u2014putting the ESP32 into sleep mode\u2014still consumes power and will eventually drain the battery, even in the \u201coff\u201d state. <\/p>\n\n\n\n

This project is sponsored by\"\"<\/a><\/p>\n\n\n\n

Using a single push-button to switch power on led me to design a separate circuit that allows that same button to both switch the power on and off, while the total current consumption in the \u201coff\u201d state is only a few microamps. <\/p>\n\n\n\n

Een Nederlandse vertaling<\/a> van de post kunt u hier<\/a> vinden.<\/p>\n\n\n\n

This is the complete schematic:<\/p>\n\n\n

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The schematic is quite simple and consists of only a few components. I chose the easy route and used a standard module for charging the Li-Ion battery (18650). I also used a standard step-up module to boost the battery voltage to 5 volts. <\/p>\n\n\n\n

Operation of the Soft Power Latch Circuit<\/strong><\/h1>\n\n\n\n

Initial state (off)<\/strong><\/h2>\n\n\n
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The battery is connected to the circuit (V+).<\/p>\n\n\n\n