Teensy 3.1 I/O Extension

For the still ongoing Graupner mc-17 remote control update project, I need more I/O channels from the Teensy 3.1. By default it breaks out 28 breadboard friendly pins, but on the bottom are another 14+ solder pads with more analogue and digital I/O. By mounting the Teensy 3.1 upside-down, these solder pads become quite accessible:

Teensy 3.1 Extended (bottom is top) Teensy 3.1 Extended (top is bottom)

Back to the mc-17 Remote Control

After the Maker Faire, I went back to the Graupner mc-17 remote control.

The arduino library from tronixstuff for the KTM-S1201 LCD which is also using a mPD7225 controller was a good starting point. But to get the LCD up and running, it took quite a bit of fiddling and logic sniffing.

Logic Pirate attached to the mc17 LCD Logic Pirate
Open Logic Sniffer for mc17 LCD

mc17 LCD mapping of bytes and bitsOnce the controller allowed me to switch on individual segments of the LCD, I needed to adapt my implementation to this specific display, as it offers remote control specific elements unusual for normal LCDs. With a proper mapping of bits and bytes to their respective LCD elements, it was easy to implement the usual alpha-numerical characters. Each of the digits is controlled by a word / two bytes. For each byte, one bit is used to control one of the additional symbols like colons, dots, or remote controls specific texts.



mc-17 working with teensy-3.1 & XBee

With all the connections for the analogue sticks, the analogue output, the lcd-control, and the buttons, the 28 standard pins of the Teensy 3.1 were used up. In order to connect the XBee Pro S2B with the Teensy, I had to use the solder-pads on the bottom of the pcb. After all the work was done, I realised that using those pads for Serial2 instead of the standard pins was more difficult than anticipated. Thanks to the tips from the PJRC Teensy community forum, I managed to get the serial link working.

Teensy 3.1, XBee Pro S2B, and Graupner mc-17

With all the peripherals set up, I still have to figure out how to drive the lcd, as the panel used in the mc-17 differs from the standard alpha-numeric ones.

Updating an old Remote Control

I recently replaced the controller of my old Graupner mc-17 remote control with a current ARM Cortex-M4 @ 96MHz (Teensy 3.1). Yesterday I soldered the sockets for the LCD, the buttons, and the ammeter which gives me access to almost all peripherals (only the power switch and the additional linear channel are still missing). I already found an Arduino library for the LCD controller NEC mPD7225, thanks tronixstuff, but the display which Graupner used differs from the standard one. Basically the LCD works, but the demo sketch just gives scrambled output. I guess I’ll have to reverse-engineer this application specific LCD.

mc-17 with new Teesny 3.1 micro-controller
Graupner mc-17 top

New Tinker Toys

In the recent weeks I found more time for tinkering and received a whole range of new toys: Two bread-board friendly micro-controller boards (Embedded Artists’ LPC1343 QuickStart Board and PJRC Teensy 3.1), the Pi NoIR Camera, two XBee Pro S2B serial RF modules, and plenty of other i2c sensors and generic tinkering supplies. On the EA QuickStart Board, which uses the same MCU as the r0ket, I’m running the microBuilder LPC1343 Code Base and the Teensy 3.1 is Arduino compatible which enables me to make use of a huge range of ready-made libraries for pretty much all my breakout boards.
Embedded Artists LPC1343 QuickStart Board PJRC Teensy 3.1 XBee Pro S2B

One of my current projects is to exchange the micro-controller of my old Graupner mc-17 remote control with the Teensy 3.1. I removed the old processor board and added contacts to all the existing connections: 2X6 poles for analogue measurements of the sticks and trims, and 2X8 poles for the LCD controller and the buttons. The LCD controller is a NEC mPD7225 for which I already found a data sheet. Via the 12bit analogue output of the Teensy, I can even drive the old analogue ammeter at the front of the remote! 🙂
Graupner mc-17 top Graupner mc-17 original controller removed Graupner mc-17 teensy 3.1 controller

Let’s see how well this mc-17 > Teensy 3.1 > XBee ~ XBee > Teensy 3.1 remote control chain works 😉