Transistor Radiosonde Balloon Telemetry Transmitter Board Version 2.

Based on the ©1964 design of project #27 from 103 Simple Transistor Circuits for a “Telemetering Transmitter” but added 2nd channel TX control, and filtering for 27 MHz un-licensed ISM Band. Using mostly period technology - keeping BJT only NPN Si types vs. PNP. The only “modern” component added is the white LED Beacon. Definitely overdone.

More details on Github and my site: Project27

Davis ISS Receiver with TFT LCD Display. Uses Moteino with 915MHz RFM69 module.

Simple Transistor Balloon Payload Transmitter Board Version 1. It is a “Modernized” Project #27 from 103 Simple Transistor Circuits ©1964 using NPN Si Transistors vs. the original’s PNP Ge transistors. This was originally intended to be a balloon payload that transmits temperature info on the 11-meter or 10-meter bands. For scale the battery holder is a AAA cell.

Apollo uDSKY’s Registers Sign Digits

Working!

This board will allow a pretty good substitute for the non-existent compatible LED sign digits for an Apollo DSKY display. You will also need the DS_MASK.brd for each display if you want the displays to be more segment-ty? There are also some additional masking and diffusing techniques that can be done to make these look really good.

NOTES:

This is intended to be used with a 0.39" 10-pin LED displays such as LTS-4301G that were used on the uDSKY display.

The minus (-) are controlled by the standard G - Segment Pin 1 with 2 LEDs in series. The (+) is a combination of the “g1” and “g2” Segs and the vertical segments (some times referred to as “h” and “J”) which are connected to the “DP” pin 6. The Common pins are 8 and 3. Because both displays are two LEDs in series this should simplify non-MUX displays as well.

https://www.jameco.com/z/LTS-4301G-Lite-On-Electronics-Green-7-Segment-LED-Display_2227911.html

When selecting the SMT LEDs make sure you get them close to the brightness and color wavelength. For example , these LED displays have: 569 nm (green) and an avg. intensity = 2200 µCD @ If =10mA.

I will post some details on how to put these together. But basically, you need to diffuse the light or the viewing angle gets critical. I used a simple piece of scotch tape but hot melt glue may also work. A couple of baffles between the G and the vertical segments are also needed or when only (-) is displayed the other segments are still slightly visible. I used a couple scrap pieces of black wire insulation wedged between the segments to block this.

The parts placement is pretty simple, The anode of the first LED connects to the respective pin. The two LED’s cathodes and anodes for each segment are connected together. The cathodes of the 2nd LEDs connect to the common pins. If you forget one LED or get one in backwards… no light! The Eagle Files are at:

https://github.com/b-wave/uDSKY/tree/master/uDSKY%20Hardware/DSKY_DISP

Use two 0.1" 5-pin headers to hold the two boards together. Mount the header on top of this board (long pins go thru the board) Then put the mask board on top of the header. The boards are separated by the plastic header. Push the pins flush to the top MSK_Brd Pins 1, 6, 8, and 3 now have to be soldered on the bottom of this board. You can solder the mask board’s pins all in place if you want to - after you verify everything is working OK of course, there are no electrical connections.

MINI DSKY Sign digit light mask

This board is the mask board for the sign displays for R1, R2 and R3 on the Apollo uDSKY project. You will need 1 ea. for each display. DS_PLUS1.brd

https://github.com/b-wave/uDSKY/tree/master/uDSKY%20Hardware/DSKY_DISP