June 2024

Pic club meeting held  11/6/24 via jitsi.

Present : Alex, Martin, Lino, Steve, John Matthews. 

For Large file transfers try  Just beam it (Martin) or Swiss Transfer (Lino). 

Steve showed the Xiao mini footprint esp32 dev board. It also has an onboard lipo charger.  I've had connection problems with the USBC-USBC cable and programs not uploading.  This is widely reported online also, so Seeedstudio may have a bug to fix.   I moved to a USBA-USBC cable and it uploads OK.

The XIAO is a good solution if you have limited space.

Wemos D1 Mini modules  Alex

My project was about the use of Wemos D1 Mini modules to replace HC-05 bluetooth serial modules.

Hardware: 2 x Wemos D1 Mini ESP8266 modules  ($6.70 each, local supply)

Software: ESP-Link Wifi-Serial Bridge from Jeelabs

Project status:

-installed Python

-installed esptools

-downloaded ESP-Link

-programmed 2 Wemos with ESP-Link firmware

-Wemos creates a wifi AP with SSID ESP_<mac addr>

-Connect to SSID and browse to 192.168.4.1 for home page.

-To do: test transparent serial bridge between Wemos modules.

Martin showed a wearable esp32 with blood oxygen sensor and accelerometer , a home made sleep sensor.  Added i2s audio microphone, $8.45 eBay Inmp441.  Blood oxygen sensor works over i2c, cable length of 1m works ok!  Has pull ups on the SDA SDC lines. 

Lino discussed accordions coming in from the USA without useable power supplies.  There are various power supplies with different connector options and voltages.  D9, 12v barrel cntr and midi, and 5v and switch. So he's made a psu to suit.    Will also have a battery option with buck/boost to generate the 12 & 5.

Power banks often shut off if current is too low.   There are circuits to keep a power bank awake by applying a timed load, see Great Scott.

 Lino was involved with a project that applied a timed dummy load to truck lights to stop the truck management system reporting a faulty light bulb, the problem was that the LEDs drew much less current.  The European trucks only used incandescent bulbs, not LEDs.  Why didn't they have LED lights on the trucks? Do LEDs have a problem in cold weather?