Thursday, September 14, 2017

Remixed WiFiChron board

Thanks to all buyers who waited patiently for the new batch of re-designed WiFiChron PCBs to arrive.
The new board eliminates the need for the 2 extra wires on the back (that connected Rx and Tx to ESP8266). The XBee socket, intended for the $45 GPSBee, was also dropped, and replaced with a 3-pin header, used for connecting the $5 GPS modules available on ebay.

Here is the list of notable changes:
  • the only RTC now supported is DS3231;
  • DS3231 is now powered from the regulated 3V3;
  • GPS module is now connected to D17 (already supported in software);
  • as mentioned above, Rx and Tx already connected to ESP8266 module (no need to solder the 2 wires on the back); as before, remember to unplug the ESP8266 module from its socket when uploading a new sketch;
This is how the new board looks like.

And below is the new schematic (compatible with the old one, just re-mixed):

The latest release of the WiFiChron software should still work unchanged with the new board.

On the assembly front, youtuber 12voldvids put together this nice video:

Here is another video on WiFiChron, courtesy of RayS:

If anyone else would like to make and publish videos on any of my kits, I will gladly support it, with explanations/clarifications and, obviously, discounts :)

Monday, July 24, 2017

IV-3 VFD confusion

So you want to build Axiris's IV-3 shield for Arduino, sourcing the IV-3 VFD tubes yourself, from any of the numerous ebay sellers, as I did.

Firstly, it is important to note that, although the assembly manual for IV-3 shield refers to it as "IV-3/IV-3a/IV-6 VFD shield for Arduino", which would make you think one could install either IV-3, IV-3A or IV-6 tubes, this is not quite the case. The reason is the difference in pin configuration:
  • IV-3: 9-segment + dot, 14 pins (1 not connected)

(pin configuration is bottom view)
  • IV-3A and IV-6: 7 segment + dot, 12 pins (1 not connected)
(pin configuration is bottom view)
  • and then, there is IV-3 v-82, which I bought on ebay: 7 segment + dot, 14 pins (3 not connected)
(pin configuration is top view)

IV-3 v-82 (as I named it, based on the printing on the back of the tube), is an amalgamation between IV-3 and IV-3A:
- can be found in either 7 segment or 9 segment (+ dot), although only 7 segments are connected;
- has 14 pins (as to support a 9 segment digit + dot), with 3 not connected;
- pin sequence differs from both IV-3 and IV-3A;
- the "key" (the trimmed unconnected pin) is on the opposite side compared to IV-3/IV-3A.
Below are some photos, with the "axiris" IV-3A on the left.

(Also notice the color of the ceramic insulator, white for the "axiris" IV-3A, pink for the IV-3 v-82.)

To adapt the IV-3 v-82 tube to the Axiris board, the pins need to be scrambled like this:

which leads to this ugly assemblage:

It would probably work with proper heat-shrink tubing around the tube terminals, but I preferred to order the correct IV-3A for which the board was designed.

Conclusion: Pay attention when (and if) you order the tubes for "Axiris IV-3 VFD shield" separately. The sure bet is to order IV-3A, with the white ceramic insulator, and the trimmed pin on the right side (when looking at the digit).

P.S. Also, make sure the tubes are "mirrory" black at the top. If the top is white, then the tube is damaged for sure, air got in the tube (basically the tube's glass is cracked), like in the photo below (right tube is damaged).