Tiny Solar Energy Module (TSEM)

For the HackadayPrize 2018 I designed a Tiny Solar Energy Module. It is cool because it can harvest enough energy from indoor light to power simple BLE or LoRa applications. I am selling two boards on Tinde for $24.90. One stores it's energy into a Li-ion battery, EAMLION, and the other stores it into a pair of supercapacitors, AEMSUCA. The AEMSUCA is really cool because now you can make applications that runs forever from indoor light without a battery!

Tiny Solar Energy Module project on Hackaday.io
https://hackaday.io/project/159139-tiny-solar-energy-module-tsem

AEMLION project on Hackaday.io
https://hackaday.io/project/160376-solar-harvesting-into-li-ion-battery

AEMSUCA project on Hackaday.io 
https://hackaday.io/project/160470-solar-harvesting-into-supercapacitors

AEMLION is sold on Tindie  for $24.90
https://www.tindie.com/products/jaspersikken/solar-harvesting-into-li-ion-battery/

AEMSUCA is sold on Tndie for $24.90
https://www.tindie.com/products/jaspersikken/solar-harvesting-into-supercapacitors/

In May/June I have designed the 1x1 inch Tiny Solar Energy Module to take part in the HackadayPrize2018 Power Harvesting challenge and won! And then I received a lot of interested in selling it. However since most projects have different power demands and people want to choose their own solar panel, I decided to remove the onboard solar cells and make two even tinier designs derived from the TSEM. They are both 0.8x0.6 inch small. The first is the AEMLION which is charging a Li-ion battery and the second is the AEMSUCA which charges a pair of supercapacitors. 

I will be selling the AEMLION and AEMSUCA on Tindie for $24.90. At the moment ELecrow is working on 50 assemblies of each.

I have fitted this 110mAh 3.0x20x25mm Li-Po battery under the TSEM PCB between the header connectors using double sided tape and soldered the wires. It's great because it still fits on a a bread board. It's really compact. 

Then I grabbed my BLE temperature humidity sensor, connected it to the 1.8V output.

It works great. I love it!

Today I have received 11 mother PCBs. I have ordered them just to make sure the TSEM eagle library part is correct. So I have soldered the TSEM to it and it's great. They came at a ridiculously low proce of $4.90 for 10, and $4.99 for shipping. I received them 10 days after ordering! Thank you Elecrow for making fast beautiful and cheap PCBs.

Today I have received TSEM R2 PCBs and a solder stencil from Elecrow.

I really like the white soldermask. I actually dont like the silkscreen lines that indicate component outline, I will remove those in a next revsion.  I've put all components except the solar cells in the solder paste and used a hot air gun to reflow. The solar cells I soldered using the soldering iron, because they asre sensitive to excessive heat. 

Then it was time for the first test and I measured that the 3.3V and the 1.8V outputs were working. 

I am happy

I was refreshing the Hacakday.com website for a few days now and finally I read the good news

https://hackaday.com/2018/07/24/twenty-power-harvesting-projects-headed-to-the-hackaday-prize-finals/

The views counter is currently at 2.5k. Let's see next week where it increases to.

I have revised the PCB because I want to use the AEM10941 LOW voltage output. So now the TSEM has two regulated output voltages; a 3.3V output (80mA) and a 1.8V output (20mA). I have just ordered the PCBs from Elecrow. 

To easily integrate TSEM into other Eagle designs I published an Eagle library with the TSEM R1 and R2 symbol and footprint.

To make sure the library part is correct I have designed a mother PCB. A PCB to solder the TSEM to. I have ordered the PCBs from Elecrow for just $4,99. It' amazingly cheap! I expect them in 2 weeks.

I have this $13.50 BLE Temperature Humidity Sensor that advertizes the values every second. I measured average current is about 50uA. That's a bit too high current for indoor light harvesting with the two tiny solar cells, but you get the idea. If I would program the a BLE sensor I would make it advertise every 8 seconds to make it low power enough.

It is not a great idea to use the 3.3V output to power a device that is designed for 1x AAA battery. The AEM10941 harvesting IC also has a second regulated output voltage, which is 1.8V. That is lower power because it is efficiently stepped down from the battery voltage using a buck converter. In the next revision of the design I will break out the 1.8V output to the castellated via's

I saw this article on Hackaday.com about the  this BQ25504 Ultra low power Solar LiPo Charger sold by Kris Winer on Tindie. I wish that article was about my TSEM. Here I compare the differences with my TSEM. The BQ25504 is very similar to AEM10941 but it does not have two integrated outputs (3.3V and 1.8V). The BQ25504 Solar Cell LiPo Charger board does not have on board solar cells, it cannot be surface mount soldered, it requires more external passives, and the mppt Voc ratio cannot be changed without changing the passive components.