First of all I would like to thank all of those who preordered the TrH Meter kits during the fundraising campaign that we ran on Tindie. It’s because of your support that we successfully launched this project. Please follow the soldering instructions provided below while building the TrH Meter.
The kit contains total 29 items that are listed here.
The TrH Meter board contains all through-hole components except for IC2, which is the AMS1117-5.0 regulator IC in SOT-223 surface mount package. You should consider soldering this component first. It’s easier to solder a SMT package on a bare PCB than a populated one. Next solder all low profile components including resistors, LDR and diode.
Next solder the capacitors, DIP IC sockets, switches and DC power supply connector. C1 is a polarized tantalum capacitor, so make sure you place it’s positive lead (which is usually longer than the cathode lead) to the hole marked with ‘+’.
Solder the DHT11 sensor and four seven segment LED modules next. You can place the DHT11 sensor straight vertical or bend its legs at right angles to place it horizontal on PCB surface. Make sure Pin 1 of DHT11 goes to VCC hole on the PCB. After soldering the display modules, you can peel off the plastic cover from the display module for better readability.
You can solder the ICSP header if you want to modify/update the firmware. Otherwise it is optional, as the PIC microcontroller is already programmed.
Now your project is ready to be powered. You can use a 6-12V DC wall adapter to power the TrH Meter. SW1 is a three position slide switch for ON/OFF, Fahrenheit or Celsius temperature selection. Once turned on, allow the sensor about 30 seconds for stable readings. If you want to play around with the firmware, visit the main document page to get the source code.