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--- projects:blinker:work_logs:3_electronics [2022/01/31 04:23] – tjhowse
+++ projects:blinker:work_logs:3_electronics [2022/02/27 05:40] (current) – tjhowse
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+~~NOCACHE~~
 ====== The Electronics======
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 D renders. The capacitors are actually 38mm high, far more than shown here, but I don't know how to resize the models used in this render.
+===== The Waiting =====
+Unfortunately I timed the PCB order to perfectly align with Chinese new year.
+{{:projects:blinker:work_logs:pasted:20220203-003706.png}}
+===== Assembly =====
+{{:projects:blinker:work_logs:pasted:20220224-131812.png}}
+Finally!
+The PCBs arrived and I soldered on one 25F supercap, the ISP header and two 2x1 SIL headers. I set my benchtop PSU to 2.8v and connected it to the solar panel input. It started drawing several amps as the caps charged up. I quickly dialled down a 100mA current limit, and the voltage slowly increased to the limit of the zener.
+===== Programming =====
+I had quite a lot of trouble getting the firmware onto them:
+  * USB extension to my workbench was too long,
+  * 3.3v/5v selector needs to be on 5v,
+  * The firmware in the USPasp was too old to support TPI,
+  * The JP3 jumper was not installed, this is required to enable 1 MHz programming speeds,
+  * I had to use Zadig to install the libusbK v3.1.0.0 driver,
+  * Arduino IDE reporting avrdude failure when it was actually succeeding.
+After solving all of those problems I eventually got some basic code onto it and and recorded a progress video.
+===== Video =====
+{{ youtube>G8RZ3I4DSik?large }}
 ===== Next Time =====
-There are a few major shortcomings to this design. It does not efficiently collect energy from the solar panel. I could get some extra energy by employing Maximum Power Point Tracking (MPPT). Also, the useful voltage range of the capacitors is between 1.8v and 2.4v. The maximum is set by the zener diode, and the minimum is set by the microcontroller. If I used a boost converter, such as a LM27313, TPS6122x, LTC3108 or TPS61021, I could decrease the usable minimum capacitor voltage to 0.5v, giving us more available energy over a full discharge.
+There are a few major shortcomings to this design. It does not efficiently collect energy from the solar panel. I could get some extra energy by employing Maximum Power Point Tracking (MPPT). A single ZSPM4523AA1 would give me MPPT, reverse current protection (replacing the schottky diode) and voltage regulation (replacing the zener diode). Also, the useful voltage range of the capacitors is between 1.8v and 2.4v. The maximum is set by the zener diode, and the minimum is set by the microcontroller. If I used a boost converter, such as a LM27313, TPS6122x, LTC3108 or TPS61021, I could decrease the usable minimum capacitor voltage to 0.5v, giving us more available energy over a full discharge.
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