7/7/23 New log

Development log moved to Hackaday.io

30/3/23 New battery

I have redesigned the power supply so that it uses 18650 li-ion batteries. 18650 batteries is a common type of battery, and is much easier to source that the old lipo battery. It is also mounted in a battery holder, so that it can be replaced easily if the battery degrades with use and age. just keep in mind that a high current rated battery (30A+) is needed. The power supply do draw 30A, but i found that the internal resistance of lower rated batteries gets to high resulting in the a voltage level out of the battery of less than 2.5V which in turn is the minimum for the internal boost converter. the 18650 battery also has almost twice the amount of stored energy. An other change is larger screws with hex heads and encoders with smaller shafts. To fit the new battery the power supply body is 2 mm thicker, but the shorte encoder shafts allows knobs that is 4 mm shorter, making the power supply in total 2 mm thinner. I've also got some nice new packaging that.

25/10/22 Rev 8 online

In my quest to make the Pbp more affordable I decided to replace the big 4.5" display with a 1.8" display. Most of the big screen was anyways left blank and never used, and the cost of the big display was almost half of the total BOM cost. When the display got smaller, suddenly the hole power supply could get smaller. I therefore did a big update on the pcb and the enclusure to reduce their size. The total dimensions of the supply is now 85x60x25mm. The linear regulator part of the electronics also got an upgrade/change. Doctorandus_P on eevblog's forum made me aver of that what I used two LM3080 (expensive, out of stock) can be done better with a NPN transistor and a feedback loop. After tweaking a few capacitor values this seems to work just as well.

7/2/22 New MCU

During assembely of the new rev 5 board I was unlucky and accentually send 27V into my last CY8C5867AXI-LP024's 3V3 pin and it released all of its magic blue smoke. I did not think that would be a big problem because i had a stock of CY8C5568AXI-060 that I thought I could use as a replacement. I new that CY8C5568AXI-060 was obsoleate, but i did not know how obsolete it was. Turns out it is not supported by the programming software anymore and eaven if you install the oldest software vertion that is in the archive on cypresses websight, you can not use a modern programber to upload the software, and the old programmers is no longer in sale. Trying to find a other replacement part form cypress did not lead anywhere, everything is out of stock verywhere. Out of stock was also the state for most other mcu brands i cheked out, but long story short, i sutmbled up on resberrry pies RP2040 whitch for some reason seams to still be in stock. Gues they have a diffrent target customer and has not been affected that badly by the component shortages. By swiching the display comunication form a 16 bit parall interface to SPI interface i mangaged to get the pincount down to less than the 28 pins that RP2040 has avilable, and I have just sendt a new vertion of the pcb with a rp2040 footprint to production.

24/2/22 rev 5 sendt to production

gerber files for the pcb is sendt to production. I am trying out jlcpcb.com (not pcbway.com) this time. The webpage and prices and capabilityes seems better so far. Time will show how the quality of the pcb are when the arrive. On this new vertion of the pcb the battery system is redesigned, now I am using 6 small batteryes in series in setead of one large one. This eliminates the need for a boost konverter(whitch is gone) and only a buck converter is needed. New battery setup needs a new charger setup, and to not have to deal with battery ballancing i have 6 separate chargers. The on/off circutri is also updated. in stead of just a switch a pushbutton and some transistors is used. this allows for a chrging symbol to show on the display when charging and the device is off, and also to automaticly power off when battery levels get low.

7/2/22 Going public

To day I have started to create a public repotory and wiki to share this project with anyone that may be intrested. The site is still just a skelleton, but atleast it is online