software creative
I built my own pcb to run a 328. This is really a continued test of learning ki-cad. All the ki-cad part footprints were accurate. Initial testing of the power regulator was positive (pun intended). I will do an ISP test soon. There is no USB chip on the board, as its really a footprint prototype. It does require an Atmel ISP to program. I did hand solder all the surface mount chips. The gunk around the MCU is flux.
I participated in the 2016 Teensy Kickstarter for the 3.5 and 3.6. Because PJRC is just the next town over, I received my units like the next day.
The backlog of projects needing attention is growing. I attached the 3.3V regulators for these boards that I’m giving to Ivan. The smaller board is a simple 555 flasher board. I’m transitioning from Upverter to Kicad and needed to verify some footprints.
It took me nearly six months, but I finally sourced a CA3020. I tried AliExpress and eBay several times. I think I purchased four from different vendors on AliExpress; in every instance they did not have any in stock. I tried a few purchases on eBay from Chinese vendors with the same result. I finally found an individual in Romania who had one. I paid like USD$20 including shipping (ouch)
The pcb’s with my final revisions for the boost regulator arrived from pcbs.io. I’ve tested this module on a breadboard. The VOUT is designed to plug right into breadboard rails. I’m surprised that the NCP1402 can boost from as low as 0.2 volts. In hindsight I wish I had made the zener diode surface mount.
I purchased this cute “little” transistor tester on Amazon. There are two models, the higher end one has USB connectivity. This test device checks diodes, LED’s, transistors, and some other PN junction devices.
I’m sitting here playing with it. Generating graphs of parts I’ve bought from Mouser and Aliexpress.
This first chart is a eight samples of blue LED’s I purchased on ebay many years ago.
Here are 8 ish samples of one watt LED’s. Huge variation here. Only two of them would actually emit light with the tester (they all emit photons when hooked up to a higher current power supply).
Here are three samples of what I think are counterfeit Mitsubishi 2SC3133 purchased on Aliexpress.
Last, here is a set of eight BD139 transistor purchased from Mouser. This plot shows hFE/Ic. 50% of the samples cluster right on average.
This will be an interesting tool to gainer deeper insight into the components I buy and stock. I hope it will make it easier to identify out of spec components purchased from Aliexpress (but honestly I’ve stopped purchasing from there because of the counterfeit problems.)
I made progress on the barn door star tracker. A few weeks ago I got the switches debounced (in software). I put labels on the control box. The control box hangs on the bottom of the platform. It’s attached at one side for easy access. The control box has the two switches and an LED mounted on it. Inside the box is an EasyDriver and a Teensy 3.1. The batteries won’t fit in the box, so I mounted them on the other end of the platform.
I’ve written enough of the software to get the reset “program” working. If you click the momentary switch towards reset, then it will lower the platform until the limit switch is triggered. I’ve got the “run” program sketched out so I know the motors will move. The next step is to measure the actual speeds and introduce the math equation to make it the motor speed track the Earth’s rotation.
One of the building block projects I”m working on is a small boost regulator that can take a coin cell or two AAA’s and boost the voltage to 5V (or 3V with a part swap) for use with an AVR or Attiny (or your favorite mcu).
The NCP1402 series of boost regulator’s costs about $0.72 in single quantity. The NCP1402SN50T1G I’m using can take a voltage as low as 1.8V and boost it to 5V at up to 200ma. The NCP1402 is a smd. This project also gives me an excuse to try using a new service from Digistump called pcbs.io. The photos below are prototype boards from pcbs.io
On vacation this past week, we visited Crater Lake National Park twice. The weather was 70F on July 5th and low 50’s on July 8th. The park was typically busy for the holiday week. Rim Village was super packed. There is a lot of construction starting on the roads. East Rim Road was still closed. The trail down to the lake is going to be closed for the season on August 15th. The mosquitoes are out in force; Klamath County has several reported cases of West Nile virus, so bring the bug spray.
I took these photos with my Sony A6000 and a Sony 10-18mm lens. When the sun was out I could shoot at ISO 100. I post processed these with ON1 Photo 10.
My oldest child is moving into middle school. He is very creative and expressed a small interest in doing some robotics. He’s enjoyed the ozobot since it was purchased.
I set out to put together something cheap (in case he loses interest, but still functional and expandable at a high level). I found a cheap (like usd$9) acrylic robot on Aliexpress, an off brand Arduino UNO, and a SainSmart motor shield. The total for this project is so far under $30. Sensor and LED bling have not yet been added. I have piles of ultrasonic and infrared sensors already. I’m thinking of adding a few perimeter contact switches and that would complete it.
