I recently received MightyHat R4 kits and assembled one. In general, the instructions are complete and clear. Thank you Felix.
- The MightyHat Features page mentions 2 general purpose buttons; but the assembly instructions do not include them. The pictures show the locations, so installation was easy.
- The 3D printed standoffs between the Pi and the MH have inside holes too big to engage the provided screws. I threaded the holes for 3mm screws and used them instead.
- Since Felix was out of stock for LCD modules, I ordered my kits without displays and sourced them elsewhere. Perhaps because of this, all of the provided screws were short (not a problem for me since I was not using the provided screws), and no display spacer was included. The instructions should mention if the spacer is unnecessary.
- I was unable to power the Pi without a 1000uF capacitor, which was not included. See https://lowpowerlab.com/forum/mightyhat/mightyhat-and-pi3-powerup-issue-(solved)/ (https://lowpowerlab.com/forum/mightyhat/mightyhat-and-pi3-powerup-issue-(solved)/). Unfortunately the 1000uF capacitors I have on hand are 35V and almost 1/2" in diameter, which makes for an ugly installation.
As an aside, it would be nice to be able to detect when the battery is fully charged in the ATMega328 so the display could be changed from "CHRG" to "CHGD" at that time.
I'm going to try to add a wire from the MCP73831 Status pin to D8 of the 328 for this purpose.[OOPS] That's a bad idea since D8 is used for the flash chip select.
Thanks again Felix for a well thought out product.
Tom
Hi Tom,
Thanks for the feedback and being nice. I think I said before that I did not really intend to make a new MH batch. Just pressure from folks... Kits are quite a lot of work for ... not a lot of return.
I likely made a lot of kitting mistakes with this latest batch I made. I ended up changing the layout and a rabbit hole takes you in places you don't want to go.
Anyway the standoffs were fixed after the first few kits I shipped. A printer bed leveling issue made me think they are OK after trying them (I must have tried just the bottom of a single standoff and hitting go on a large batch). Bummer... detected that afterwards as it usually happens.
I liked the nokia LCDs because they are low power and high contrast in the sun. But they are ... so .. so .. so poorly made in china, and a bit low resolution, and a bit bulky. Many failed and were DOA and they were just a nuissance to stock. So for those reasons I stopped carrying them. Like I mentioned, a next rev will likely use the smaller OLEDs or something else.
In my haste I likely omitted including the cap in your kit, my apologies. I can send you one, although even a smaller cap should help, even a 100uF rated 6V or more...
The buttons will likely be replaced with SMD buttons in a future rev also. The fewer TH components the better.
Felix,
I have an assortment of electrolytic capacitors; only the 1000uF is so big. On my next build, I will experiment with 100uF to 680uF caps to see if they will work.
Smiles,
Tom
Here is a suggested assembly order, slightly modified from Felix's:
- SMA antenna connector. Step A. Hints: VERY gently squeeze the ground lugs of the connector a very little bit; just enough that the connector doesn't slide around while you are soldering it. It was easiest for me to solder the middle signal connection before the ground lugs.
- RST tactile button. Step B.
- 2.1 power jack if desired and included. Step B.
- Battery slide switch. Step C.
- FTDI header if desired (not included in kit).
- 2 general purpose buttons (the tall ones). Spread the contacts slightly so they stay in the holes while soldering.
- Buzzer if desired and included. Step D.
- Red/Green tactile button. Step E.
- Extension header (if you have one). Step F.
- Attach standoffs. Felix's step 1 (after step F).
- Mating header. Step 2. Note that if you have installed an extension header, you probably need to solder all 40 pins on the mating header to ensure the signals are passed to the extension header.
- 1000uF capacitor. Step 3.
- If using an LCD display, LCD using the included 1×8 header. Step 4.
The rest of Felix's assembly instructions.
Tom