Updates are hard, especially when I can't say "Things are moving quicker than planned and I'm surpassing all your expectations!"
I mentioned in the last update, that due to the chip shortage, I was forced to swap microcontrollers for the Computer Engineering for Babies books. I thought this was going to be pretty straightforward. I redesigned the circuit board according to the pinout of the new microcontroller, did some tests to make sure that I could read the values of the lights sensors, that I could toggle the LED, read the button state, etc. Sent off the files to have some sample boards made, waited, and waited, and got back sample circuit boards. I expected that I would just change a few variables in the code, and then be able to give the thumbs up to go ahead to fire up the smelters.
Of course that didn't happen. When I loaded the sample circuit boards into books and powered them on, they seemed to work great, except for the first page. For some reason when the book was shut, and all the sensors should be pretty much totally dark, the book thought that it was open to the last page with all of the sensors seeing light. The ADC (the part of the chip that converts voltages from the light sensors, to numbers that I can access in the code), wasn't working when the sensors were dark. The old chip had no trouble, but with this new chip the ADC didn't want to work correctly on the low end. This was a real low point for me. Initially, I tried to solve the problem by throwing money at it. I was frantically buying samples of every other microcontroller that I thought might work. I bought amplifier circuits hoping I could buffer the signal to solve the problem. Resistors. Capacitors. Anything.
The smartest thing I did, was to phone a friend. I called my smartest friend, and this update wasn't supposed to be an email about life lessons, but here's a freebee: Most often, it doesn't matter how smart you are, as long as you have some really smart friends that are willing to drive an hour to help you troubleshoot what should be a simple circuit. My buddy Zack came over and together we sat on the floor for three hours next to my darkest closet with a bunch of wires connected to a breadboard plugged into my computer. Zack had some awesome suggestions, and we reworked the board to adjust the ADC so instead of measuring from 3 volts all the way down to 0, we offset the sensors to bring them off of the floor. So now we only have to measure from 3 volts down to 1.5 volts. There were some tricks to do this successfully, but I'll spare you the technical details (if you really want them, you can read them here).
Together we got it all resolved. I reworked the circuit board again, told the manufacturer that I need samples as soon as they can do them. And I now have a tracking number for 5 new sample boards, that should be here next week. When I get them, I'll just update a few variables in the code, and then pull the trigger
I'm just now realizing that I've been lying to myself for the last 3 weeks. Optimistically, circuit boards will be completed before June, and the books can be done by mid July. It usually takes about 25 days on the boat, so by the time I get the books and start shipping them it will be August. Damn.
One of the highlights since the last email update is that, I received 6,000 books on Easter Sunday and am almost completely finished shipping them all out to the first backers through Kickstarter. And feedback has been really positive.
Here are some email snippets from the last day that made me smile:
"It arrived this afternoon & I am super pleased with it & read it with my 1yr old straight away."
"Well done on a very clever & superbly constructed book!"
"This was really worth the wait, great job with the book! Especially appreciated the included stickers for different “target groups”!!"
"With kickstarter one never knows ... But this - this is just amazing!!!! Idea, execution, quality, ... everything is just perfect. As somebody else said below - it brings lots of smiles!"
"Just received our order and absolutely loved it! I showed it to my 10 month old son and he is absolutely amazed by the buttons and lights. I see a future engineer in the making!"
"Just a follow up that my daughter loves the book. Esp how it light's up lol."
"My 13 month old daughter LOVES this. It kept her occupied all through her first flight - she preferred it to the tablet! Such clever programming and construction. Can't wait to see what edition #2 brings"
Seriously, it's hard to send out update emails when I have to admit that I'm running into snags and there are delays. I am trying to be honest, and transparent with this whole project, and that has been one of the goals with this project from the beginning. With each update there is a wave of disappointed people, and sometimes a few angry people; I can understand that. (side note, the target age range for this is probably 1-5 years. You're 6 month old baby probably isn't going to age out of this anytime soon). But I have also always been pleasantly surprised by the number of understanding and encouraging emails, which sending updates a lot easier and more enjoyable. So thank you. Thank you so much for the support even when there are hiccups. And I hope that you find it's worth the wait.