Archives March 2017

Friday, 31st March 2017 - 09:00:51


Level shifter powers up. No smoke. Unfortunately it doesn't work correctly because there is more current coming into the base of each transistor than I anticipated. It's enough to hold all transistors on. So I'll try getting some mosfets with the same pinout and seeing how they do.

Sunday, 26th March 2017 - 15:06:48


Playing with the battery powered ESP8266 project again. I've got it down to 9mA. Unfortunately the minium current draw is raised a long way by the buck converter board I have which is rated for 3A - it's much heavier duty than it needs to be and isn't very efficient.

Friday, 24th March 2017 - 22:29:56


Been prototyping some new esp8266 boards to have them run on a pair of 18650s. The current draw when asleep is down to 0.7mA which is pretty nice. Unfortunately it goes up to 70mA when hooked to wifi and transmitting. This is usually only for a few seconds every five minutes or so.

Friday, 17th March 2017 - 09:10:47


I had a go at some SMD soldering with solder paste for the level converter board. It came out OK.

Wednesday, 8th March 2017 - 22:46:11


So I scored a failed Juniper SRX210 off eBay for $1. I figured it was worth a gamble. Well it paid off. After some testing I found that the system was not getting any juice. The input protection diode had failed short. My guess is that someone has plugged in the PSU for the POE version of this firewall (48VDC) into this non-POE firewall (should be 12VDC) and nuked it. I removed it temporarily and powered the unit up on a lab power supply to limit the current. It booted! Score!

Wednesday, 8th March 2017 - 10:49:17

12V to 24V Level Shifter PCB

The PCB for the 12V to 24V has arrived.

Friday, 3rd March 2017 - 09:05:33


Ebay score: Cisco 1230G access points which will be used to create a wireless bridge.

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